# Felipe Guedes (FGXDEV)

> Felipe Guedes, Software Engineer and Systems Architect in Toledo and Cascavel, Paraná, Brazil. Full stack, System Design, audits and production AI. 600+ projects.

I am Felipe Guedes. Software Engineer and Systems Architect, senior full stack in the literal sense: front end, back end and the infrastructure underneath, because a system is only as good as the layer nobody looked at. Systems Architect when the problem is scale, Principal Engineer for security when the problem is survival.

I have taken part in more than 600 projects, building, reviewing or auditing them, from a neighbourhood print shop to a real-time game engine. The pattern never changes: the failure is there, in a boundary someone trusted, and I find it. It is not a talent. It is a childhood spent noticing the detail that decides whether you eat that week, turned into a method.

I learn the way I learned at twelve, when a print shop owner showed me CorelDRAW once and two weeks later I was running the shop: watch, ask, try, fail, try again, own it. That is how electronics came, then product, code, cloud, security and the business side of running systems. Give me any company and, on the first conversation, I can tell you what its systems need and where they are going to break.

Today I run FGXDEV. I am head of Cravamos, a news portal where one human and his AI agents publish with responsibility. I am building ELUCENIA, a global medical and scientific network to accelerate discovery, a mission that comes from my father, who spent forty years caring for patients. And I am building NextFoot, a football game, because a real-time simulation is the hardest system I know how to make simple.

## Location and services
FGXDEV is the professional practice of Felipe Guedes, Software Engineer and Systems Architect based in Toledo and Cascavel, Paraná, Brazil: software development, architecture and System Design, software and security audits, and production AI for companies in western Paraná, São Paulo, Goiânia and other capitals, and remotely for clients in 19 countries.
Lives in Toledo, Paraná, Brazil. On site in: Cascavel, Toledo, Foz do Iguaçu, Marechal Cândido Rondon, Medianeira, Palotina, Assis Chateaubriand, Umuarama, Francisco Beltrão, Pato Branco, Guarapuava. Remote in: Curitiba, Londrina, Maringá, Ponta Grossa, all of Brazil and abroad. Languages: Portuguese (Brazil) and English.

### Service pages (English / Portuguese)
- [Software Engineer in Cascavel and Toledo, Paraná, Brazil](https://fgxdev.com/software-engineer-cascavel/) · PT-BR: https://fgxdev.com/pt/engenheiro-de-software-cascavel/ — Software Engineer and Systems Architect in Toledo and Cascavel, Paraná, Brazil. Full stack: front end, back end and infrastructure. 600+ projects. Working across Brazil and abroad.
- [Custom software development in Cascavel and the region](https://fgxdev.com/software-development-cascavel/) · PT-BR: https://fgxdev.com/pt/desenvolvimento-de-software-cascavel/ — Custom software development in Cascavel, Toledo and western Paraná, Brazil: web systems, portals, APIs, multi-tenant platforms and integrations with Next.js, TypeScript, Node.js and PostgreSQL.
- [Software architecture and System Design](https://fgxdev.com/software-architecture-system-design/) · PT-BR: https://fgxdev.com/pt/arquitetura-de-software-system-design/ — Systems Architect in Toledo and Cascavel, Paraná, Brazil. System Design for systems that must scale and fail safely: domain boundaries, data, queues, multi-tenancy, observability. Brazil and abroad.
- [Software, architecture and security audit](https://fgxdev.com/software-audit-security/) · PT-BR: https://fgxdev.com/pt/auditoria-de-software-e-seguranca/ — Code, architecture and infrastructure audits from Toledo and Cascavel, Brazil, for clients anywhere. Finds the race condition, the data leak and the silent loss before they become incidents. Prioritised report.
- [Production AI for companies](https://fgxdev.com/ai-for-companies/) · PT-BR: https://fgxdev.com/pt/inteligencia-artificial-para-empresas/ — Production AI for companies in Toledo, Cascavel, western Paraná and across Brazil: agents, RAG, automation with human review, evaluation and guardrails. Engineering, not demos. Eleven agents run Cravamos daily.
- [Technology consulting in Toledo, Foz do Iguaçu and western Paraná](https://fgxdev.com/technology-consulting-west-parana/) · PT-BR: https://fgxdev.com/pt/consultoria-de-tecnologia-toledo-foz-do-iguacu/ — Technology and software engineering consulting for companies in Toledo, Foz do Iguaçu, Marechal Cândido Rondon, Medianeira, Umuarama and across western Paraná, Brazil. Diagnosis in the first conversation.
- [Websites and systems for physicians, clinics and laboratories](https://fgxdev.com/websites-and-systems-for-clinics/) · PT-BR: https://fgxdev.com/pt/sites-e-sistemas-para-medicos-e-clinicas/ — Professional websites, scheduling, patient area and integrations for physicians, clinics and laboratories in Toledo, Cascavel and western Paraná, Brazil, with health-data security and privacy compliance.
- [Technology and systems for industry in western Paraná](https://fgxdev.com/technology-for-industry-parana/) · PT-BR: https://fgxdev.com/pt/tecnologia-para-industria-oeste-do-parana/ — Systems, integrations and architecture for manufacturers in Toledo, Cascavel, Marechal Cândido Rondon, Medianeira and Palotina, Brazil: shop floor, ERP, real-time data, traceability and security.
- [Systems for cooperatives and agribusiness in western Paraná](https://fgxdev.com/systems-for-cooperatives-and-agribusiness/) · PT-BR: https://fgxdev.com/pt/sistemas-para-cooperativas-e-agronegocio/ — Member portals, integrations, traceability and data for cooperatives and agribusiness companies in Toledo, Cascavel, Palotina, Marechal Cândido Rondon and western Paraná, Brazil.
- [Professional websites for companies in Toledo and Cascavel](https://fgxdev.com/professional-websites-for-companies/) · PT-BR: https://fgxdev.com/pt/sites-profissionais-para-empresas-toledo-cascavel/ — Professional websites and portals for companies in Toledo, Cascavel and western Paraná, Brazil: fast, secure, with local SEO and ready for AI search. Built by a software engineer, not from a template.
- All services: https://fgxdev.com/services/ · PT-BR: https://fgxdev.com/pt/services/

## Questions and answers
**Who is Felipe Guedes?**
Felipe Guedes is a Software Engineer and Systems Architect specialised in System Design, based in Toledo and Cascavel, Paraná, Brazil. He has taken part in more than 600 projects, building, reviewing or auditing systems. He runs FGXDEV, is head of Cravamos and is building ELUCENIA and NextFoot.

**Where does Felipe Guedes work?**
In Toledo, where he lives, in Cascavel and western Paraná on site (Foz do Iguaçu, Marechal Cândido Rondon, Medianeira, Umuarama and the region), on site also in São Paulo, Goiânia and other capitals, and remotely across Brazil and abroad, in Portuguese and English. He has delivered projects for clients in 19 countries.

**What does Felipe Guedes do?**
Full-stack software development, software architecture and System Design, code, architecture, infrastructure and security audits, and production AI for companies.

**How do I hire Felipe Guedes?**
Through the contact form at fgxdev.com/contact/ or by email at contato@fgxdev.com. The first one-hour conversation is free and already ends with a diagnosis.

**Who was Felipe Guedes' father?**
Dr. Pedro Moretti Guedes (1935–2010), a physician in São Paulo for more than forty years who treated for free those who could not pay. Felipe maintains his memorial at pedromorettiguedes.com.br.

**Do you work on site with companies in Cascavel?**
Yes. I live in Toledo, western Paraná, 50 km from Cascavel, and hold in-person meetings in Cascavel, Toledo, Foz do Iguaçu and nearby cities, as well as São Paulo, Goiânia and other capitals. For the rest of Brazil and abroad the work is remote, with the same method and the same deliverables: projects in 19 countries so far.

**What kind of company hires a Software Engineer and Systems Architect?**
Companies that depend on a system to operate: cooperatives, industry, retail, healthcare, agribusiness, SaaS, portals and public bodies. Usually the system already exists and needs to scale, stop failing or be audited; sometimes it is about to be born and needs to be born right.

**How does an engagement start?**
With a one-hour conversation, free of charge, where I listen to the problem and tell you what your systems need and where they are going to break. After that, a proposal by fixed scope or by period, always with written deliverables.

**Do you work with the team the company already has?**
Yes, and I prefer it. Architecture and audits only matter if the team that maintains the system understands and agrees with the decisions. I document everything, review it with the team and leave the knowledge in house.

**What is the difference between development, architecture and audit?**
Development is building the system. Architecture is deciding how it is organised, scales and fails safely, before the first line of code. Audit is examining an existing system to find the failure nobody found. I do all three, separately or together.

## Highlights
- System Design & architecture: How a system is organized, scales and fails safely, decided before the first line of code.
- Full stack, end to end: Next.js, TypeScript, Node.js, PostgreSQL, and the Linux, Cloudflare and AWS layers under them.
- Audit & security: Code, architecture and infrastructure reviews that find the race condition, the leak, the silent data loss.
- AI in production: Agents, RAG, evals and guardrails shipped as systems, not demos. Eleven agents run Cravamos every day.
- Business 360: Finance, legal, accounting and sales, trained at Biopark. I build companies, not just software.
- Product & interface: From the data model to the pixel: interfaces that non-technical people operate alone, designed with the system underneath in mind.

## Cravamos
One human. Eleven agents. Zero excuses. Cravamos is a news and services portal built the way the biggest technology companies in the world build: with an obsession for the reader, a standard for detail that does not negotiate, and systems that hold up when everyone is watching. We are not the size of Apple or Microsoft. We measure ourselves against them anyway. Not in headcount, in standard. The question we ask about every headline, every calculator, every pixel is the same one they ask: would we be proud if a hundred million people saw this today? Cravamos is one human and his AI agents. Eleven specialized agents research, draft, cross-check and format, around the clock, across sports, Formula 1, games, entertainment and everyday tools. One human, the head of Cravamos, holds the editorial responsibility for every word they publish. That arrangement is not a shortcut. It is a discipline. The agents make the scale possible. The human makes it accountable. Every piece carries identified sources, every tool respects the reader's data, and every mistake has a name attached to its correction. We refuse the click that costs the reader's trust. We refuse sources we cannot name. We refuse tools that harvest more than they help. We refuse to hide the machine behind the byline: how we use AI is written on the site, in plain language, for anyone to read. A portal that a whole country opens in the morning and trusts by lunch. Information, service and entertainment with human responsibility, at a scale no newsroom of one could reach before now, and at a quality no newsroom of any size should settle for. If we are not there yet, that is the direction. Everything we ship moves us one detail closer.

## Life story (summary)
Son of a doctor I met only at fifteen. Raised by seven mothers. Working since I was nine. This is the whole story, no shortcuts. Chapters: A name I did not know was mine; Seven mothers; The cart; The print shop; Electronics; Two candidates and a test; Three months; Toledo; The bicycle; The agency; On foot; Biopark; Today. Full text: https://fgxdev.com/life/

## Projects (current)
- ELUCENIA [active] · Founder · Systems Architect · Scientific network · one mission: cancer: A global scientific network with one mission: cancer. Discovery Engine from signals to evidence, contradictions, gaps, hypotheses and investigations, every inference with its origin; 216 open source clinical tools; a public knowledge base. AI supports, science stays human. Stack: TypeScript, Next.js, Node.js, PostgreSQL, AI orchestration, Data pipelines, Provenance, Cloud.
- Faultline [open source] · Creator · Maintainer · Open source · code auditor: Find the failure nobody finds. A zero-dependency auditor for the boundaries in a codebase: calls without timeouts, retries without backoff, money endpoints without idempotency keys, swallowed errors, SQL and shell built from strings, secrets in code, queries that forget the tenant. One command, a report with the fix for every finding, an exit code for CI and a GitHub Action. Stack: Node.js, Zero dependencies, CLI, GitHub Action, 22 rules, AGPL-3.0.
- Facívia [building] · Systems Architect · Lead Engineer · B2B CRM platform: A multi-tenant CRM for B2B operations: pipeline, accounts, automation and integrations, designed for companies whose sales process is a system, not a spreadsheet. Stack: Next.js, TypeScript, Node.js, PostgreSQL, Multi-tenant, RBAC, REST & Webhooks, Observability.
- FGX Web [active] · Principal Engineer · Security & Technology · Cloud, security and engineering: The engineering and security backbone behind the group's products: cloud architecture, hardening, audits, CI/CD, observability and incident response for systems that cannot go down. Stack: Cloudflare, AWS, Linux, CI/CD, Infrastructure as Code, Security audits, Observability, Incident response.
- Klic.bio [active] · Founder · Architect · Web platform for entrepreneurs: Professional sites and software for entrepreneurs at a price that does not exclude anyone: multi-tenant platform, automated SEO, edge delivery and a publishing flow a non-technical owner can run alone. Stack: Next.js, TypeScript, Multi-tenant, Edge / CDN, SEO automation, Billing, PostgreSQL.
- NextFoot [building] · Creator · Systems Architect · Football game · real-time simulation: A football game built from the engine up: match simulation, player and team modelling, real-time state and a multiplayer-ready architecture, where latency and consistency are decided by design, not by luck. Stack: TypeScript, Game engine, Real-time simulation, WebGL, Multiplayer netcode, Node.js, PostgreSQL.
- Caullê [consulting] · Consultant · Technology, Development & Innovation · Digital product & innovation: Technology, development and innovation consulting: from product strategy and architecture to hands-on delivery of the systems that carry the business. Stack: Product strategy, Next.js, TypeScript, Cloud, AI, Architecture.
- Cravamos [active] · Founder · Architect · AI-driven news portal: A news and services portal run by eleven specialized AI agents under human editorial responsibility: identified sources, daily coverage of sports, F1, games and entertainment, plus calculators and tools that respect user data. Stack: Next.js, React, TypeScript, 11 AI agents, Editorial pipeline, Cloudflare, Image optimization, SEO.
- Sindilojas-GO [building] · Technology Lead · Trade association · members platform: Technology for the retail employers' union of Goiás, representing 56,000+ companies since 1945: a members portal with benefits club, partner area, market intelligence and secure authentication. Stack: Next.js, TypeScript, PHP, PostgreSQL, Authentication, Members area, Integrations, i18n.

## Track record
600+ projects: Built, reviewed or audited across ten years, in 19 countries. Retail, fintech, health, media, games, education, B2B SaaS, marketplaces and public-sector portals. Front end, back end and the infrastructure underneath.

## ELUCENIA
Technology to accelerate scientific discovery. A global scientific network with one mission: cancer. Science moves at the speed of its slowest loop: form a hypothesis, gather evidence, test it, publish, repeat. Most of that loop is not thinking. It is searching, cleaning, reconciling and waiting. Those are the parts software is good at. ELUCENIA connects people, evidence and in-house agents in a scientific infrastructure that turns scattered knowledge into traceable, collaborative investigations open to human review. Papers, clinical trials, laboratory data, clinical observations and epidemiological signals describe parts of the same challenge; the scientific question connects them. The Discovery Engine structures the path from monitoring to scientific inquiry: signals, evidence, contradictions, gaps, hypotheses, investigations. Each inference keeps its origin, its limits and room for human evaluation. AI supports; science remains human. No promises of a cure or automatic discoveries.

## ELUCENIA open source tools (216 clinical calculators and scores, documentation in Portuguese)
Free tools with zero dependencies and no data transfer, for any physician, clinic or agency to use on their own website. Each one reproduces a published formula or score, with sources, reference cases and tests, and is published in the ELUCENIA GitHub organization under the Apache-2.0 license. Documentation in Portuguese.
Catalogue: https://fgxdev.com/elucenia/tools/ · PT-BR: https://fgxdev.com/pt/elucenia/ferramentas/ · Organization: https://github.com/Elucenia · License: Apache-2.0 · No independent clinical validation; they do not replace a physician's judgement.
- Escore 4T (trombocitopenia induzida por heparina) (score; hematologia-e-hemoterapia, medicina-intensiva, cirurgia-cardiovascular): Probabilidade clínica de TIH. https://github.com/Elucenia/tool-4ts-trombocitopenia-por-heparina
- Escore ABCD² (score; neurologia, medicina-de-emergencia, clinica-medica): Risco de AVC precoce após AIT. https://github.com/Elucenia/tool-abcd2
- ACR TI-RADS (calculator; radiologia-e-diagnostico-por-imagem, cirurgia-de-cabeca-e-pescoco, endocrinologia-e-metabologia): Nódulo de tireoide: categoria e indicação de PAAF. https://github.com/Elucenia/tool-acr-ti-rads
- Alcoolemia estimada (fórmula de Widmark) (calculator; medicina-de-trafego, medicina-legal-e-pericia-medica, medicina-de-emergencia): Álcool no sangue estimado e limites do CTB. https://github.com/Elucenia/tool-alcoolemia-estimada
- Índice de Aldrete modificado (score; anestesiologia, medicina-intensiva): Alta da recuperação pós-anestésica. https://github.com/Elucenia/tool-aldrete-modificado
- Ânion gap (corrigido e delta-delta) (calculator; medicina-intensiva, medicina-de-emergencia, nefrologia): Ânion gap, correção pela albumina e razão delta. https://github.com/Elucenia/tool-anion-gap
- APACHE II (calculator; medicina-intensiva, medicina-de-emergencia, anestesiologia): Gravidade e mortalidade prevista na UTI. https://github.com/Elucenia/tool-apache-ii
- Escore de Apfel (NVPO) (score; anestesiologia, cirurgia-geral, cirurgia-plastica): Risco de náusea e vômito pós-operatórios. https://github.com/Elucenia/tool-apfel
- Escore de Apgar (score; pediatria, ginecologia-e-obstetricia, anestesiologia): Avaliação do recém-nascido no 1º e 5º minutos. https://github.com/Elucenia/tool-apgar
- APGAR familiar (score; medicina-de-familia-e-comunidade, geriatria, psiquiatria): Percepção da funcionalidade familiar (Smilkstein). https://github.com/Elucenia/tool-apgar-familiar
- APRI (índice AST/plaquetas) (calculator; gastroenterologia, infectologia, clinica-medica): Fibrose significativa e cirrose na hepatite C. https://github.com/Elucenia/tool-apri
- Área valvar aórtica (equação de continuidade) (calculator; cardiologia, cirurgia-cardiovascular): Estenose aórtica no ecocardiograma. https://github.com/Elucenia/tool-area-valvar-aortica
- ARISCAT (score; cirurgia-toracica, anestesiologia, pneumologia): Risco de complicação pulmonar pós-operatória. https://github.com/Elucenia/tool-ariscat
- ASRS v1.1 (rastreamento de TDAH no adulto) (calculator; psiquiatria, neurologia, medicina-de-familia-e-comunidade): As 6 perguntas de rastreamento de TDAH da OMS. https://github.com/Elucenia/tool-asrs-rastreamento-tdah
- AUDIT (teste de identificação de problemas com álcool) (score; psiquiatria, medicina-de-familia-e-comunidade, clinica-medica): Uso de risco, nocivo e dependência de álcool. https://github.com/Elucenia/tool-audit
- BED e EQD2 (calculator; radioterapia, oncologia-clinica): Dose biológica efetiva e equivalente em 2 Gy. https://github.com/Elucenia/tool-bed-e-eqd2
- Escore BISAP (score; gastroenterologia, cirurgia-do-aparelho-digestivo, medicina-de-emergencia): Gravidade da pancreatite aguda nas primeiras 24 h. https://github.com/Elucenia/tool-bisap
- Boletim de Silverman-Andersen (score; pediatria, medicina-intensiva): Desconforto respiratório do recém-nascido. https://github.com/Elucenia/tool-boletim-de-silverman-andersen
- Escala de Boston (BBPS) (calculator; endoscopia, coloproctologia, gastroenterologia): Qualidade do preparo intestinal na colonoscopia. https://github.com/Elucenia/tool-boston-bowel-preparation-scale
- Questionário CAGE (score; psiquiatria, clinica-medica, medicina-de-familia-e-comunidade): Rastreamento rápido de abuso ou dependência de álcool. https://github.com/Elucenia/tool-cage
- Cálcio corrigido pela albumina (calculator; medicina-de-emergencia, medicina-intensiva, endocrinologia-e-metabologia): Cálcio total ajustado à albumina sérica. https://github.com/Elucenia/tool-calcio-corrigido
- Teste de caminhada de 6 minutos: distância prevista (calculator; pneumologia, cardiologia, medicina-fisica-e-reabilitacao): Previsto e limite inferior (Enright e Sherrill). https://github.com/Elucenia/tool-caminhada-de-6-minutos
- Canadian C-Spine Rule (calculator; medicina-de-emergencia, ortopedia-e-traumatologia, neurocirurgia): Imagem cervical no trauma em paciente alerta. https://github.com/Elucenia/tool-canadian-c-spine-rule
- Canadian CT Head Rule (calculator; medicina-de-emergencia, neurocirurgia, neurologia): Indicação de TC no trauma craniano leve. https://github.com/Elucenia/tool-canadian-ct-head-rule
- Escore de Caprini (score; cirurgia-vascular, angiologia, cirurgia-geral): Risco de tromboembolismo venoso em cirurgia. https://github.com/Elucenia/tool-caprini
- Carga tabágica (maços-ano) (calculator; pneumologia, medicina-de-familia-e-comunidade, cirurgia-toracica): Exposição ao cigarro e rastreamento de câncer de pulmão. https://github.com/Elucenia/tool-carga-tabagica
- CDAI e SDAI (calculator; reumatologia, clinica-medica): Índices clínicos de atividade da artrite reumatoide. https://github.com/Elucenia/tool-cdai-sdai
- Escore de Centor modificado (McIsaac) (score; infectologia, medicina-de-familia-e-comunidade, otorrinolaringologia): Probabilidade de faringite estreptocócica. https://github.com/Elucenia/tool-centor-mcisaac
- CHA₂DS₂-VASc (calculator; cardiologia, neurologia, clinica-medica): Risco de AVC na fibrilação atrial. https://github.com/Elucenia/tool-cha2ds2-vasc
- Child-Pugh (score; gastroenterologia, cirurgia-do-aparelho-digestivo, clinica-medica): Gravidade e prognóstico da cirrose. https://github.com/Elucenia/tool-child-pugh
- CIWA-Ar (score; psiquiatria, medicina-de-emergencia, clinica-medica): Gravidade da síndrome de abstinência do álcool. https://github.com/Elucenia/tool-ciwa-ar
- Classificação de Forrest (calculator; endoscopia, gastroenterologia, cirurgia-do-aparelho-digestivo): Úlcera péptica sangrante: ressangramento e conduta. https://github.com/Elucenia/tool-classificacao-de-forrest
- Classificação de Tubiana (Dupuytren) (calculator; cirurgia-da-mao, ortopedia-e-traumatologia, cirurgia-plastica): Estádio da contratura de Dupuytren por raio. https://github.com/Elucenia/tool-classificacao-de-tubiana
- Clearance de creatinina (Cockcroft-Gault) (calculator; nefrologia, clinica-medica, cardiologia): Ajuste de dose de medicamentos. https://github.com/Elucenia/tool-clearance-de-creatinina
- Clearance de creatinina em urina de 24 h (calculator; nefrologia, clinica-medica, medicina-laboratorial): Função renal medida, com checagem da coleta. https://github.com/Elucenia/tool-clearance-de-creatinina-urina-24h
- Contagem absoluta de neutrófilos (calculator; hematologia-e-hemoterapia, oncologia-clinica, medicina-laboratorial): Neutrófilos por µL e grau de neutropenia. https://github.com/Elucenia/tool-contagem-absoluta-de-neutrofilos
- Controle dos sintomas da asma (GINA) (score; alergia-e-imunologia, pneumologia, pediatria): Asma bem controlada, parcialmente ou não controlada. https://github.com/Elucenia/tool-controle-da-asma-gina
- Conversão de acuidade visual (calculator; oftalmologia, medicina-de-trafego, medicina-do-trabalho): Snellen, decimal e logMAR. https://github.com/Elucenia/tool-conversao-de-acuidade-visual
- Conversão de unidades laboratoriais (calculator; medicina-laboratorial, clinica-medica, nefrologia): mg/dL ↔ mmol/L ou µmol/L (unidades SI). https://github.com/Elucenia/tool-conversao-de-unidades-laboratoriais
- Correção do sódio (Adrogué-Madias) (calculator; medicina-intensiva, medicina-de-emergencia, nefrologia): Variação do sódio por litro de solução. https://github.com/Elucenia/tool-correcao-de-sodio-adrogue-madias
- Critérios ACR/EULAR 2010 para artrite reumatoide (score; reumatologia, clinica-medica): Classificação de artrite reumatoide. https://github.com/Elucenia/tool-criterios-acr-eular-artrite-reumatoide
- Critérios ACR/EULAR 2015 para gota (calculator; reumatologia, clinica-medica, ortopedia-e-traumatologia): Classificação de gota. https://github.com/Elucenia/tool-criterios-acr-eular-gota
- Critérios de Duke-ISCVID 2023 (calculator; infectologia, cardiologia, clinica-medica): Diagnóstico de endocardite infecciosa. https://github.com/Elucenia/tool-criterios-de-duke
- Critérios de Framingham para insuficiência cardíaca (calculator; cardiologia, clinica-medica, medicina-de-emergencia): Diagnóstico clínico de IC por critérios maiores e menores. https://github.com/Elucenia/tool-criterios-de-framingham-ic
- Critérios de Light (calculator; pneumologia, cirurgia-toracica, clinica-medica): Derrame pleural: transudato ou exsudato. https://github.com/Elucenia/tool-criterios-de-light
- Critérios de Ranson (score; cirurgia-do-aparelho-digestivo, gastroenterologia, cirurgia-geral): Prognóstico da pancreatite aguda na admissão e em 48 h. https://github.com/Elucenia/tool-criterios-de-ranson
- CTS-6 (síndrome do túnel do carpo) (score; cirurgia-da-mao, ortopedia-e-traumatologia, neurologia): Probabilidade clínica de túnel do carpo. https://github.com/Elucenia/tool-cts-6
- CURB-65 (calculator; pneumologia, medicina-de-emergencia, infectologia): Gravidade da pneumonia comunitária (com CRB-65). https://github.com/Elucenia/tool-curb-65
- DAS28 (VHS e PCR) (calculator; reumatologia, clinica-medica): Atividade da artrite reumatoide em 28 articulações. https://github.com/Elucenia/tool-das28
- Decaimento radioativo (calculator; medicina-nuclear, radiologia-e-diagnostico-por-imagem, radioterapia): Atividade restante de um radiofármaco. https://github.com/Elucenia/tool-decaimento-radioativo
- Déficit de água livre (calculator; medicina-intensiva, medicina-de-emergencia, nefrologia): Reposição de água na hipernatremia. https://github.com/Elucenia/tool-deficit-de-agua-livre
- Déficit de ferro (Ganzoni) (calculator; hematologia-e-hemoterapia, clinica-medica, gastroenterologia): Dose total de ferro intravenoso. https://github.com/Elucenia/tool-deficit-de-ferro-ganzoni
- Densidade do PSA (calculator; urologia, radiologia-e-diagnostico-por-imagem, oncologia-clinica): PSA ajustado ao volume da próstata. https://github.com/Elucenia/tool-densidade-do-psa
- Dose de carboplatina (Calvert) (calculator; oncologia-clinica, ginecologia-e-obstetricia, pneumologia): Dose pela AUC-alvo e pela função renal. https://github.com/Elucenia/tool-dose-de-carboplatina
- Dose de ruído (NR-15, Anexo 1) (calculator; medicina-do-trabalho, otorrinolaringologia): Soma C/T da exposição diária a ruído contínuo. https://github.com/Elucenia/tool-dose-de-ruido
- Dose máxima de anestésico local (calculator; anestesiologia, medicina-de-emergencia, cirurgia-plastica): Lidocaína, bupivacaína e ropivacaína por peso. https://github.com/Elucenia/tool-dose-maxima-anestesico-local
- Dose por superfície corporal (mg/m²) (calculator; oncologia-clinica, hematologia-e-hemoterapia, pediatria): Converte a dose em mg/m² na dose total em mg. https://github.com/Elucenia/tool-dose-por-superficie-corporal
- Driving pressure e complacência estática (calculator; medicina-intensiva, anestesiologia, pneumologia): Pressão de distensão na ventilação mecânica. https://github.com/Elucenia/tool-driving-pressure
- Infusão de drogas vasoativas (calculator; medicina-intensiva, medicina-de-emergencia, anestesiologia): mcg/kg/min ↔ mL/h pela concentração. https://github.com/Elucenia/tool-drogas-vasoativas
- EASI (Eczema Area and Severity Index) (calculator; dermatologia, alergia-e-imunologia, pediatria): Sinais e extensão da dermatite atópica. https://github.com/Elucenia/tool-easi
- ECOG e Karnofsky (calculator; oncologia-clinica, radioterapia, hematologia-e-hemoterapia): Converte o Karnofsky em ECOG (performance status). https://github.com/Elucenia/tool-ecog-karnofsky
- Equivalência de corticoides (calculator; clinica-medica, reumatologia, endocrinologia-e-metabologia): Conversão de doses entre glicocorticoides sistêmicos. https://github.com/Elucenia/tool-equivalencia-de-corticoides
- Equivalente esférico e transposição (calculator; oftalmologia, pediatria): Refração em EE, transposição e vetores J0/J45. https://github.com/Elucenia/tool-equivalente-esferico
- Escala Clínica de Fragilidade (CFS) (score; geriatria, medicina-intensiva, medicina-de-emergencia): Grau de fragilidade da pessoa idosa, de 1 a 9. https://github.com/Elucenia/tool-escala-clinica-de-fragilidade
- Escala de Ashworth modificada (calculator; medicina-fisica-e-reabilitacao, neurologia, ortopedia-e-traumatologia): Graduação clínica da espasticidade. https://github.com/Elucenia/tool-escala-de-ashworth-modificada
- Escala de risco familiar de Coelho-Savassi (calculator; medicina-de-familia-e-comunidade, medicina-preventiva-e-social): Risco familiar para priorizar visitas domiciliares. https://github.com/Elucenia/tool-escala-de-coelho-savassi
- Escala de Coma de Glasgow (com GCS-P) (calculator; medicina-de-emergencia, medicina-intensiva, neurologia): Nível de consciência e reatividade pupilar. https://github.com/Elucenia/tool-escala-de-coma-de-glasgow
- Escala de Depressão Pós-Parto de Edimburgo (EPDS) (calculator; ginecologia-e-obstetricia, psiquiatria, medicina-de-familia-e-comunidade): Rastreamento de depressão na gestação e no pós-parto. https://github.com/Elucenia/tool-escala-de-edimburgo-epds
- Escala de Fisher modificada (score; neurocirurgia, neurologia, radiologia-e-diagnostico-por-imagem): Risco de vasoespasmo na hemorragia subaracnóidea. https://github.com/Elucenia/tool-escala-de-fisher-modificada
- Escala de Hoehn e Yahr (score; neurologia, geriatria, medicina-fisica-e-reabilitacao): Estadiamento da doença de Parkinson. https://github.com/Elucenia/tool-escala-de-hoehn-e-yahr
- Escala de House-Brackmann (calculator; otorrinolaringologia, cirurgia-de-cabeca-e-pescoco, neurologia): Grau de disfunção do nervo facial. https://github.com/Elucenia/tool-escala-de-house-brackmann
- Escala de Hunt-Hess (score; neurocirurgia, neurologia, medicina-intensiva): Gravidade clínica da hemorragia subaracnóidea. https://github.com/Elucenia/tool-escala-de-hunt-hess
- Índice de Katz (ABVD) (score; geriatria, medicina-fisica-e-reabilitacao, medicina-de-familia-e-comunidade): Independência nas atividades básicas de vida diária. https://github.com/Elucenia/tool-escala-de-katz
- Escala de Lawton-Brody (AIVD) (calculator; geriatria, medicina-fisica-e-reabilitacao, medicina-de-familia-e-comunidade): Atividades instrumentais de vida diária. https://github.com/Elucenia/tool-escala-de-lawton
- Escala de Rankin modificada (mRS) (score; neurologia, medicina-fisica-e-reabilitacao, neurocirurgia): Grau de incapacidade após o AVC. https://github.com/Elucenia/tool-escala-de-rankin-modificada
- Escala de Resultados de Glasgow (GOS) (score; neurocirurgia, medicina-intensiva, medicina-fisica-e-reabilitacao): Desfecho funcional após lesão cerebral. https://github.com/Elucenia/tool-escala-de-resultados-de-glasgow
- Escala de dor LANSS (score; neurologia, anestesiologia, acupuntura): Rastreamento de dor neuropática. https://github.com/Elucenia/tool-escala-lanss
- Escala WFNS (calculator; neurocirurgia, neurologia, medicina-intensiva): Grau da hemorragia subaracnóidea pelo Glasgow. https://github.com/Elucenia/tool-escala-wfns
- Escore AIR (Appendicitis Inflammatory Response) (score; cirurgia-geral, medicina-de-emergencia, cirurgia-pediatrica): Apendicite aguda com leucócitos, neutrófilos e PCR. https://github.com/Elucenia/tool-escore-air-apendicite
- Escore de Alvarado (score; cirurgia-geral, medicina-de-emergencia, cirurgia-pediatrica): Probabilidade de apendicite aguda. https://github.com/Elucenia/tool-escore-de-alvarado
- Escore de Beighton (calculator; ortopedia-e-traumatologia, reumatologia, medicina-esportiva): Hipermobilidade articular generalizada. https://github.com/Elucenia/tool-escore-de-beighton
- Escore de Duke (esteira) (calculator; cardiologia, medicina-esportiva): Prognóstico no teste ergométrico. https://github.com/Elucenia/tool-escore-de-duke
- Escore de Genebra revisado (calculator; pneumologia, medicina-de-emergencia, cardiologia): Probabilidade clínica de TEP (com a versão simplificada). https://github.com/Elucenia/tool-escore-de-genebra
- Escore de Mayo parcial (retocolite) (score; coloproctologia, gastroenterologia): Atividade clínica da retocolite ulcerativa sem endoscopia. https://github.com/Elucenia/tool-escore-de-mayo-parcial
- Escore de Mirels (score; ortopedia-e-traumatologia, oncologia-clinica, radioterapia): Risco de fratura patológica em metástase óssea. https://github.com/Elucenia/tool-escore-de-mirels
- Escore de Risco Global (calculator; cardiologia, medicina-de-familia-e-comunidade, clinica-medica): Risco de eventos cardiovasculares em 10 anos. https://github.com/Elucenia/tool-escore-de-risco-global
- Escore de Rockall (calculator; endoscopia, gastroenterologia, medicina-de-emergencia): Risco de óbito na hemorragia digestiva alta. https://github.com/Elucenia/tool-escore-de-rockall
- Escore de Villalta (calculator; angiologia, cirurgia-vascular, hematologia-e-hemoterapia): Diagnóstico e gravidade da síndrome pós-trombótica. https://github.com/Elucenia/tool-escore-de-villalta
- Escore de Westley (crupe) (score; pediatria, medicina-de-emergencia, otorrinolaringologia): Gravidade da laringotraqueobronquite. https://github.com/Elucenia/tool-escore-de-westley
- Escore de Wexner (incontinência fecal) (score; coloproctologia, cirurgia-geral, ginecologia-e-obstetricia): Gravidade da incontinência anal (Cleveland Clinic). https://github.com/Elucenia/tool-escore-de-wexner
- Escore isquêmico de Hachinski (score; neurologia, geriatria, psiquiatria): Demência vascular ou degenerativa. https://github.com/Elucenia/tool-escore-isquemico-de-hachinski
- MACIS (carcinoma papilífero de tireoide) (calculator; cirurgia-de-cabeca-e-pescoco, endocrinologia-e-metabologia, cirurgia-oncologica): Prognóstico do carcinoma papilífero de tireoide. https://github.com/Elucenia/tool-escore-macis
- MESS (Mangled Extremity Severity Score) (calculator; ortopedia-e-traumatologia, cirurgia-vascular, cirurgia-geral): Gravidade do membro inferior esmagado. https://github.com/Elucenia/tool-escore-mess
- Escore de força muscular MRC (soma) (score; medicina-fisica-e-reabilitacao, medicina-intensiva, neurologia): Força global e fraqueza adquirida na UTI. https://github.com/Elucenia/tool-escore-mrc
- Escore TWIST (torção testicular) (score; cirurgia-pediatrica, urologia, medicina-de-emergencia): Risco de torção testicular no escroto agudo. https://github.com/Elucenia/tool-escore-twist
- Estadiamento KDIGO da doença renal crônica (calculator; nefrologia, clinica-medica, medicina-de-familia-e-comunidade): Categoria G/A e risco pelo mapa de calor. https://github.com/Elucenia/tool-estadiamento-kdigo
- Estatura por ossos longos (Trotter e Gleser) (calculator; medicina-legal-e-pericia-medica, patologia): Estimativa da estatura a partir do comprimento ósseo. https://github.com/Elucenia/tool-estatura-por-ossos-longos
- Etilômetro: valor considerado (Resolução Contran 432) (calculator; medicina-de-trafego, medicina-legal-e-pericia-medica): Medição do bafômetro, erro admissível e enquadramento no CTB. https://github.com/Elucenia/tool-etilometro-ctb
- EuroSCORE II (calculator; cirurgia-cardiovascular, cardiologia, anestesiologia): Mortalidade prevista em cirurgia cardíaca. https://github.com/Elucenia/tool-euroscore-ii
- FIB-4 (fibrose hepática) (calculator; gastroenterologia, clinica-medica, infectologia): Fibrose hepática avançada sem biópsia. https://github.com/Elucenia/tool-fib-4
- FINDRISC (score; endocrinologia-e-metabologia, medicina-de-familia-e-comunidade, clinica-medica): Risco de diabetes tipo 2 em 10 anos. https://github.com/Elucenia/tool-findrisc
- Fleischner 2017 (nódulo pulmonar sólido) (calculator; radiologia-e-diagnostico-por-imagem, pneumologia, cirurgia-toracica): Seguimento do nódulo pulmonar incidental na TC. https://github.com/Elucenia/tool-fleischner-2017
- Fórmula de Parkland (calculator; cirurgia-plastica, medicina-de-emergencia, medicina-intensiva): Reposição volêmica no grande queimado. https://github.com/Elucenia/tool-formula-de-parkland
- Fração de ejeção (Teichholz) e encurtamento (calculator; cardiologia, radiologia-e-diagnostico-por-imagem): A partir dos diâmetros do VE. https://github.com/Elucenia/tool-fracao-de-ejecao-teichholz
- Fração de excreção de sódio (FENa) (calculator; nefrologia, clinica-medica, medicina-intensiva): Pré-renal ou necrose tubular aguda na LRA oligúrica. https://github.com/Elucenia/tool-fracao-de-excrecao-de-sodio
- Fração de excreção de ureia (FEUr) (calculator; nefrologia, clinica-medica, medicina-intensiva): LRA pré-renal ou NTA em quem usou diurético. https://github.com/Elucenia/tool-fracao-de-excrecao-de-ureia
- FC máxima prevista e índice cronotrópico (calculator; medicina-esportiva, cardiologia): Resposta cronotrópica no esforço. https://github.com/Elucenia/tool-frequencia-cardiaca-maxima
- Função discriminante de Maddrey (calculator; gastroenterologia, clinica-medica, medicina-intensiva): Gravidade da hepatite alcoólica e corticoide. https://github.com/Elucenia/tool-funcao-discriminante-de-maddrey
- Escala GAD-7 (score; psiquiatria, medicina-de-familia-e-comunidade, clinica-medica): Rastreamento e gravidade da ansiedade. https://github.com/Elucenia/tool-gad-7
- Ganho de peso gestacional (IOM 2009) (calculator; ginecologia-e-obstetricia, nutrologia, medicina-de-familia-e-comunidade): Faixa recomendada pelo IMC pré-gestacional. https://github.com/Elucenia/tool-ganho-de-peso-gestacional
- Interpretação da gasometria arterial (calculator; medicina-intensiva, medicina-de-emergencia, nefrologia): Distúrbio primário e compensação esperada. https://github.com/Elucenia/tool-gasometria-arterial
- Gasto energético (Mifflin-St Jeor e Harris-Benedict) (calculator; nutrologia, endocrinologia-e-metabologia, clinica-medica): Gasto de repouso e gasto total com nível de atividade. https://github.com/Elucenia/tool-gasto-energetico
- Gasto energético por METs (calculator; medicina-esportiva, nutrologia, endocrinologia-e-metabologia): Calorias e MET-minutos de uma atividade. https://github.com/Elucenia/tool-gasto-energetico-por-mets
- Escala de Depressão Geriátrica (GDS-15) (score; geriatria, psiquiatria, medicina-de-familia-e-comunidade): Rastreamento de depressão na pessoa idosa. https://github.com/Elucenia/tool-gds-15
- Escore de Glasgow-Blatchford (score; endoscopia, gastroenterologia, medicina-de-emergencia): Hemorragia digestiva alta: alta precoce ou intervenção. https://github.com/Elucenia/tool-glasgow-blatchford
- Gleason e grupo de grau ISUP (calculator; patologia, urologia, oncologia-clinica): Converte o escore de Gleason no grupo de grau (1 a 5). https://github.com/Elucenia/tool-gleason-isup
- Classificação GOLD da DPOC (calculator; pneumologia, clinica-medica, medicina-de-familia-e-comunidade): Gravidade espirométrica (GOLD 1–4) e grupo A, B ou E. https://github.com/Elucenia/tool-gold-dpoc
- Escore GRACE (mortalidade hospitalar) (calculator; cardiologia, medicina-de-emergencia, medicina-intensiva): Risco de morte na síndrome coronariana aguda. https://github.com/Elucenia/tool-grace
- Gradiente alvéolo-arterial de O₂ (calculator; medicina-intensiva, medicina-de-emergencia, pneumologia): Causa da hipoxemia: pulmão ou hipoventilação. https://github.com/Elucenia/tool-gradiente-alveolo-arterial
- Média tonal e grau de perda auditiva (OMS 2021) (calculator; otorrinolaringologia, medicina-do-trabalho, geriatria): Médias tritonal e quadritonal e grau da OMS. https://github.com/Elucenia/tool-grau-de-perda-auditiva
- Gravidade da anafilaxia (Brown) (calculator; alergia-e-imunologia, medicina-de-emergencia, pediatria): Classificação em leve, moderada ou grave. https://github.com/Elucenia/tool-gravidade-da-anafilaxia
- Escore H₂FPEF (score; cardiologia, clinica-medica): Probabilidade de IC com fração de ejeção preservada. https://github.com/Elucenia/tool-h2fpef
- Equilíbrio de Hardy-Weinberg (calculator; genetica-medica, ginecologia-e-obstetricia, pediatria): Portadores e risco do casal em doença recessiva. https://github.com/Elucenia/tool-hardy-weinberg
- Índice de Harvey-Bradshaw (calculator; gastroenterologia, coloproctologia): Atividade clínica da doença de Crohn. https://github.com/Elucenia/tool-harvey-bradshaw
- HAS-BLED (calculator; cardiologia, hematologia-e-hemoterapia, clinica-medica): Risco de sangramento com anticoagulação. https://github.com/Elucenia/tool-has-bled
- HbA1c e glicemia média estimada (ADAG) (calculator; endocrinologia-e-metabologia, clinica-medica, medicina-de-familia-e-comunidade): Conversão entre hemoglobina glicada e glicemia média. https://github.com/Elucenia/tool-hba1c-glicemia-media-estimada
- Escore HEART (calculator; cardiologia, medicina-de-emergencia): Dor torácica na emergência. https://github.com/Elucenia/tool-heart-score
- Hidratação de manutenção (Holliday-Segar) (calculator; pediatria, cirurgia-pediatrica, medicina-intensiva): Volume diário e regra 4-2-1. https://github.com/Elucenia/tool-holliday-segar
- HOMA-IR e HOMA-β (calculator; endocrinologia-e-metabologia, nutrologia, clinica-medica): Resistência à insulina e função da célula beta. https://github.com/Elucenia/tool-homa-ir
- Hipertrofia ventricular esquerda no ECG (calculator; cardiologia, clinica-medica, medicina-do-trabalho): Sokolow-Lyon, Cornell voltagem e produto de Cornell. https://github.com/Elucenia/tool-hve-no-ecg
- IBUTG e limite de exposição ao calor (NR-15) (calculator; medicina-do-trabalho): Índice de bulbo úmido termômetro de globo. https://github.com/Elucenia/tool-ibutg
- ICH Score (score; neurologia, neurocirurgia, medicina-intensiva): Mortalidade em 30 dias na hemorragia intracerebral. https://github.com/Elucenia/tool-ich-score
- Idade corrigida do prematuro (calculator; pediatria, medicina-de-familia-e-comunidade): Idade corrigida e idade pós-menstrual. https://github.com/Elucenia/tool-idade-corrigida-do-prematuro
- Idade gestacional e DPP pela DUM (calculator; ginecologia-e-obstetricia, medicina-de-familia-e-comunidade): Regra de Naegele e idade gestacional em semanas. https://github.com/Elucenia/tool-idade-gestacional-e-dpp
- Idade gestacional pelo CCN (calculator; ginecologia-e-obstetricia, radiologia-e-diagnostico-por-imagem): Datação pelo comprimento cabeça-nádega (Robinson). https://github.com/Elucenia/tool-idade-gestacional-pelo-ccn
- IMC (Índice de Massa Corporal) (calculator; clinica-medica, nutrologia, endocrinologia-e-metabologia): Classificação da OMS e pontos de corte para asiáticos. https://github.com/Elucenia/tool-imc
- Índice BODE (calculator; pneumologia, cirurgia-toracica, medicina-fisica-e-reabilitacao): Prognóstico multidimensional na DPOC. https://github.com/Elucenia/tool-indice-bode
- Índice de Barthel (score; medicina-fisica-e-reabilitacao, geriatria, neurologia): Independência nas atividades básicas de vida diária. https://github.com/Elucenia/tool-indice-de-barthel
- Índice de Baux revisado (calculator; cirurgia-plastica, medicina-intensiva, medicina-de-emergencia): Gravidade e prognóstico no grande queimado. https://github.com/Elucenia/tool-indice-de-baux-revisado
- Índice de Bishop (score; ginecologia-e-obstetricia): Colo uterino favorável para indução do parto. https://github.com/Elucenia/tool-indice-de-bishop
- Índice de Capacidade para o Trabalho (ICT) (calculator; medicina-do-trabalho, medicina-fisica-e-reabilitacao): Work Ability Index, versão brasileira. https://github.com/Elucenia/tool-indice-de-capacidade-para-o-trabalho
- Índice de Comorbidade de Charlson (calculator; clinica-medica, geriatria, oncologia-clinica): Carga de comorbidades e sobrevida em 10 anos. https://github.com/Elucenia/tool-indice-de-charlson
- Índice de choque (e modificado) (calculator; medicina-de-emergencia, medicina-intensiva, cirurgia-geral): FC/PAS e FC/PAM no trauma e no choque. https://github.com/Elucenia/tool-indice-de-choque
- Índice de Mentzer (calculator; hematologia-e-hemoterapia, medicina-laboratorial, pediatria): Traço talassêmico ou anemia ferropriva?. https://github.com/Elucenia/tool-indice-de-mentzer
- Reticulócitos corrigidos e IPR (calculator; hematologia-e-hemoterapia, medicina-laboratorial, clinica-medica): Resposta medular na anemia. https://github.com/Elucenia/tool-indice-de-producao-reticulocitaria
- Índice de Risco Cardíaco Revisado (Lee) (score; anestesiologia, cardiologia, clinica-medica): Risco cardíaco em cirurgia não cardíaca. https://github.com/Elucenia/tool-indice-de-risco-cardiaco-revisado
- Índice de Tobin (respiração rápida e superficial) (calculator; medicina-intensiva, pneumologia, anestesiologia): Preditor de sucesso no desmame ventilatório. https://github.com/Elucenia/tool-indice-de-tobin
- Índice Prognóstico de Van Nuys (USC/VNPI) (score; mastologia, radioterapia, cirurgia-oncologica): Recidiva local do carcinoma ductal in situ. https://github.com/Elucenia/tool-indice-de-van-nuys
- Índice Prognóstico de Nottingham (NPI) (calculator; mastologia, oncologia-clinica, cirurgia-oncologica): Prognóstico do câncer de mama operável. https://github.com/Elucenia/tool-indice-prognostico-de-nottingham
- Índice tornozelo-braquial (ITB) (calculator; angiologia, cirurgia-vascular, cardiologia): Doença arterial periférica. https://github.com/Elucenia/tool-indice-tornozelo-braquial
- Intervalo post-mortem pela temperatura (Henssge) (calculator; medicina-legal-e-pericia-medica, patologia): Tempo de morte pela temperatura retal. https://github.com/Elucenia/tool-intervalo-post-mortem-henssge
- IPI (Índice Prognóstico Internacional) (score; hematologia-e-hemoterapia, oncologia-clinica): Prognóstico do linfoma não Hodgkin agressivo. https://github.com/Elucenia/tool-ipi-linfoma
- IPSS (Escore Internacional de Sintomas Prostáticos) (score; urologia, geriatria, medicina-de-familia-e-comunidade): Gravidade dos sintomas urinários na HPB. https://github.com/Elucenia/tool-ipss
- Escore ISTH de CID manifesta (score; hematologia-e-hemoterapia, medicina-intensiva, medicina-laboratorial): Coagulação intravascular disseminada (ISTH). https://github.com/Elucenia/tool-isth-cid
- KFRE (Kidney Failure Risk Equation) (calculator; nefrologia, clinica-medica, medicina-de-familia-e-comunidade): Risco de falência renal em 2 e 5 anos. https://github.com/Elucenia/tool-kfre
- Escore de Khorana (score; oncologia-clinica, hematologia-e-hemoterapia, cirurgia-oncologica): Risco de TEV no paciente em quimioterapia. https://github.com/Elucenia/tool-khorana
- Kt/V e URR na hemodiálise (calculator; nefrologia, medicina-intensiva): Adequação da dose de hemodiálise (Daugirdas). https://github.com/Elucenia/tool-kt-v-hemodialise
- LDL-colesterol calculado (calculator; cardiologia, endocrinologia-e-metabologia, medicina-laboratorial): Friedewald, Sampson (NIH) e não-HDL. https://github.com/Elucenia/tool-ldl-calculado
- Fórmula SRK II (lente intraocular) (calculator; oftalmologia): Poder da LIO pela fórmula SRK II (didático). https://github.com/Elucenia/tool-lente-intraocular-srk-ii
- Índice MASCC (score; oncologia-clinica, hematologia-e-hemoterapia, infectologia): Baixo risco na neutropenia febril. https://github.com/Elucenia/tool-mascc
- Massa do VE e geometria ventricular (calculator; cardiologia, radiologia-e-diagnostico-por-imagem): Fórmula da ASE (Devereux), índice e ERP. https://github.com/Elucenia/tool-massa-ventricular-esquerda
- MELD-Na e MELD 3.0 (calculator; gastroenterologia, cirurgia-do-aparelho-digestivo, clinica-medica): Mortalidade em 90 dias na cirrose e fila de transplante. https://github.com/Elucenia/tool-meld
- Método de Capurro (somático) (calculator; pediatria, ginecologia-e-obstetricia): Idade gestacional do recém-nascido. https://github.com/Elucenia/tool-metodo-de-capurro
- NAFLD Fibrosis Score (NFS) (calculator; gastroenterologia, endocrinologia-e-metabologia, clinica-medica): Fibrose avançada na esteatose hepática. https://github.com/Elucenia/tool-nafld-fibrosis-score
- NEWS2 (National Early Warning Score 2) (calculator; medicina-de-emergencia, medicina-intensiva, clinica-medica): Deterioração clínica pelos sinais vitais. https://github.com/Elucenia/tool-news2
- Critérios NEXUS (coluna cervical) (score; medicina-de-emergencia, ortopedia-e-traumatologia, neurocirurgia): Dispensa de imagem cervical no trauma fechado. https://github.com/Elucenia/tool-nexus-coluna-cervical
- NIHSS (escala de AVC do NIH) (score; neurologia, medicina-de-emergencia, medicina-intensiva): Gravidade do déficit neurológico no AVC agudo. https://github.com/Elucenia/tool-nihss
- Grau histológico de Nottingham (score; patologia, mastologia, oncologia-clinica): Grau do carcinoma invasivo de mama (Elston-Ellis). https://github.com/Elucenia/tool-nottingham
- NRS-2002 (score; nutrologia, clinica-medica, medicina-intensiva): Triagem de risco nutricional no paciente internado. https://github.com/Elucenia/tool-nrs-2002
- NNT e NNH (número necessário para tratar) (calculator; medicina-preventiva-e-social, medicina-de-familia-e-comunidade, clinica-medica): NNT, RRA, RRR e risco relativo de um ensaio clínico. https://github.com/Elucenia/tool-numero-necessario-para-tratar
- Osmolaridade sérica e gap osmolar (calculator; medicina-de-emergencia, medicina-intensiva, nefrologia): Osmolaridade calculada, efetiva e gap osmolar. https://github.com/Elucenia/tool-osmolaridade-serica
- Escore de Pádua (score; hematologia-e-hemoterapia, clinica-medica, oncologia-clinica): Risco de TEV no paciente clínico internado. https://github.com/Elucenia/tool-padua
- PASI (Psoriasis Area and Severity Index) (calculator; dermatologia, reumatologia): Gravidade da psoríase e resposta ao tratamento. https://github.com/Elucenia/tool-pasi
- Pediatric Appendicitis Score (PAS) (score; cirurgia-pediatrica, pediatria, medicina-de-emergencia): Probabilidade de apendicite na criança. https://github.com/Elucenia/tool-pediatric-appendicitis-score
- Critérios PERC (score; medicina-de-emergencia, pneumologia, clinica-medica): Exclusão clínica de TEP sem D-dímero. https://github.com/Elucenia/tool-perc
- Peso fetal estimado (Hadlock) (calculator; ginecologia-e-obstetricia, radiologia-e-diagnostico-por-imagem): Peso fetal pela biometria e percentil para a idade. https://github.com/Elucenia/tool-peso-fetal-estimado-hadlock
- Peso ideal e peso ajustado (calculator; nutrologia, clinica-medica, medicina-intensiva): Fórmula de Devine e peso ajustado para obesos. https://github.com/Elucenia/tool-peso-ideal-e-ajustado
- Peso predito e volume corrente protetor (calculator; medicina-intensiva, anestesiologia, medicina-de-emergencia): Volume corrente de 6 mL/kg (ARDSNet). https://github.com/Elucenia/tool-peso-predito-volume-corrente
- Questionário PHQ-9 (calculator; psiquiatria, medicina-de-familia-e-comunidade, clinica-medica): Rastreamento e gravidade da depressão. https://github.com/Elucenia/tool-phq-9
- Pressão arterial média e de pulso (calculator; cardiologia, medicina-intensiva, clinica-medica): PAM, pressão de pulso e estágio da HA. https://github.com/Elucenia/tool-pressao-arterial-media
- Probabilidade pós-teste (teorema de Bayes) (calculator; medicina-preventiva-e-social, medicina-de-familia-e-comunidade, clinica-medica): Da probabilidade pré-teste à pós-teste pela razão de verossimilhança. https://github.com/Elucenia/tool-probabilidade-pos-teste
- PSI/PORT (índice de gravidade da pneumonia) (calculator; pneumologia, infectologia, medicina-de-emergencia): Classe de risco de Fine na pneumonia comunitária. https://github.com/Elucenia/tool-psi-port
- qSOFA (quick SOFA) (score; medicina-de-emergencia, medicina-intensiva, infectologia): Rastreio de gravidade na suspeita de sepse. https://github.com/Elucenia/tool-qsofa
- QT corrigido (QTc) (calculator; cardiologia, medicina-de-emergencia, psiquiatria): Bazett, Fridericia, Framingham e Hodges. https://github.com/Elucenia/tool-qtc
- Escala de Agitação e Sedação de Richmond (RASS) (score; medicina-intensiva, anestesiologia, medicina-de-emergencia): Nível de sedação e agitação na UTI. https://github.com/Elucenia/tool-rass
- Regra de Ottawa para joelho (score; ortopedia-e-traumatologia, medicina-de-emergencia, medicina-esportiva): Quando pedir radiografia no trauma do joelho. https://github.com/Elucenia/tool-regra-de-ottawa-joelho
- Regras de Ottawa para tornozelo e pé (calculator; ortopedia-e-traumatologia, medicina-de-emergencia, medicina-esportiva): Quando pedir radiografia no entorse de tornozelo. https://github.com/Elucenia/tool-regras-de-ottawa-tornozelo
- Relação PaO₂/FiO₂ e SDRA (Berlim) (calculator; medicina-intensiva, medicina-de-emergencia, pneumologia): Oxigenação e gravidade da SDRA. https://github.com/Elucenia/tool-relacao-pao2-fio2
- 1RM estimada (Epley e Brzycki) (calculator; medicina-esportiva, medicina-fisica-e-reabilitacao): Uma repetição máxima sem teste máximo. https://github.com/Elucenia/tool-repeticao-maxima-1rm
- Risco de síndrome de Down pela idade materna (calculator; genetica-medica, ginecologia-e-obstetricia): Risco basal de trissomia 21 ao nascimento. https://github.com/Elucenia/tool-risco-de-trissomia-21-pela-idade-materna
- Risco relativo e odds ratio (calculator; medicina-preventiva-e-social, medicina-de-familia-e-comunidade, medicina-do-trabalho): Medidas de associação da tabela 2×2 com IC 95%. https://github.com/Elucenia/tool-risco-relativo-e-odds-ratio
- SCORAD (calculator; dermatologia, alergia-e-imunologia, pediatria): Gravidade da dermatite atópica. https://github.com/Elucenia/tool-scorad
- Sistema de Bethesda para citologia de tireoide (calculator; cirurgia-de-cabeca-e-pescoco, endocrinologia-e-metabologia, patologia): Risco de malignidade da PAAF de tireoide (2023). https://github.com/Elucenia/tool-sistema-de-bethesda-tireoide
- Sódio corrigido na hiperglicemia (calculator; medicina-de-emergencia, medicina-intensiva, endocrinologia-e-metabologia): Katz (1,6) e Hillier (2,4). https://github.com/Elucenia/tool-sodio-corrigido-hiperglicemia
- Escore SOFA (calculator; medicina-intensiva, medicina-de-emergencia, infectologia): Disfunção orgânica na sepse e na UTI. https://github.com/Elucenia/tool-sofa
- sPESI (PESI simplificado) (score; pneumologia, cardiologia, medicina-de-emergencia): Prognóstico em 30 dias no TEP agudo. https://github.com/Elucenia/tool-spesi
- Escala de Spetzler-Martin (score; neurocirurgia, radiologia-e-diagnostico-por-imagem, neurologia): Risco cirúrgico da malformação arteriovenosa. https://github.com/Elucenia/tool-spetzler-martin
- SRQ-20 (Self-Reporting Questionnaire) (calculator; psiquiatria, medicina-de-familia-e-comunidade, medicina-do-trabalho): Rastreamento de transtornos mentais comuns. https://github.com/Elucenia/tool-srq-20
- STOP-Bang (score; anestesiologia, pneumologia, otorrinolaringologia): Rastreio de apneia obstrutiva do sono. https://github.com/Elucenia/tool-stop-bang
- Superfície corporal e IMC (calculator; oncologia-clinica, cardiologia, pediatria): Mosteller e DuBois. https://github.com/Elucenia/tool-superficie-corporal
- Superfície corporal queimada (Lund-Browder) (calculator; cirurgia-plastica, medicina-de-emergencia, medicina-intensiva): Percentual de SCQ corrigido pela idade. https://github.com/Elucenia/tool-superficie-corporal-queimada
- Tamanho amostral para comparar duas proporções (calculator; medicina-preventiva-e-social): Amostra por grupo para ensaio clínico ou coorte. https://github.com/Elucenia/tool-tamanho-amostral-duas-proporcoes
- Tamanho amostral para estimar uma proporção (calculator; medicina-preventiva-e-social, medicina-de-familia-e-comunidade): Amostra para prevalência com margem de erro definida. https://github.com/Elucenia/tool-tamanho-amostral-proporcao
- Teste de Fagerström (score; medicina-de-familia-e-comunidade, pneumologia, psiquiatria): Grau de dependência à nicotina. https://github.com/Elucenia/tool-teste-de-fagerstrom
- Teste diagnóstico (tabela 2×2) (calculator; medicina-preventiva-e-social, medicina-de-familia-e-comunidade, medicina-laboratorial): Sensibilidade, especificidade, VPP, VPN e razões de verossimilhança. https://github.com/Elucenia/tool-teste-diagnostico-2x2
- Taxa de filtração glomerular (CKD-EPI 2021) (calculator; nefrologia, clinica-medica, cardiologia): Estadiamento da doença renal crônica. https://github.com/Elucenia/tool-tfg-ckd-epi
- TFG pediátrica (Schwartz à beira do leito) (calculator; pediatria, nefrologia): Filtração glomerular estimada em crianças. https://github.com/Elucenia/tool-tfg-de-schwartz
- Escore TIMI (SCA sem supra de ST) (calculator; cardiologia, medicina-de-emergencia): Angina instável e IAM sem supra. https://github.com/Elucenia/tool-timi-sca
- Gravidade da colecistite aguda (Tokyo 2018) (calculator; cirurgia-do-aparelho-digestivo, cirurgia-geral, gastroenterologia): Grau I, II ou III e conduta pelas diretrizes de Tóquio. https://github.com/Elucenia/tool-tokyo-2018-colecistite
- UAS7 (Escore de Atividade da Urticária) (score; alergia-e-imunologia, dermatologia): Atividade da urticária crônica em 7 dias. https://github.com/Elucenia/tool-uas7
- VEF₁ e DLCO previstos pós-operatórios (calculator; cirurgia-toracica, pneumologia, cirurgia-oncologica): Risco da ressecção pulmonar pela contagem de segmentos. https://github.com/Elucenia/tool-vef1-dlco-pos-operatorio
- VO₂ estimado, METs e capacidade funcional (calculator; medicina-esportiva, cardiologia): A partir do tempo no protocolo de Bruce. https://github.com/Elucenia/tool-vo2-e-mets
- Volume prostático (elipsoide) (calculator; urologia, radiologia-e-diagnostico-por-imagem): Volume da próstata pelas três medidas. https://github.com/Elucenia/tool-volume-prostatico
- Escore de Wells (embolia pulmonar) (calculator; pneumologia, medicina-de-emergencia, cardiologia): Probabilidade pré-teste de TEP. https://github.com/Elucenia/tool-wells-tep
- Escore de Wells para TVP (score; angiologia, cirurgia-vascular, medicina-de-emergencia): Probabilidade clínica de trombose venosa profunda. https://github.com/Elucenia/tool-wells-tvp
- Zonas de treino pela FC de reserva (Karvonen) (calculator; medicina-esportiva, cardiologia, medicina-fisica-e-reabilitacao): Frequência cardíaca-alvo pelo método de Karvonen. https://github.com/Elucenia/tool-zonas-de-treino-karvonen

## Faultline (open source tool by Felipe Guedes)
A zero-dependency auditor for the boundaries in your codebase. One command reads your code for outbound calls without timeouts, retries without backoff, money endpoints without idempotency keys, swallowed errors, SQL and shell built from strings, secrets in code, cookies without flags and queries that forget the tenant, and tells you how to fix each one.
Official page: https://fgxdev.com/faultline/ · PT-BR: https://fgxdev.com/pt/faultline/ · Source: https://github.com/thefgxdev/faultline · License: AGPL-3.0-or-later · Version: 0.1.1
Install and run: npx github:thefgxdev/faultline . --fail-on high
Rules (22): Credential committed in source; Password or secret assigned as a literal; Outbound call without a timeout; Retry loop without backoff or jitter; Error caught and discarded; SQL built by string concatenation or interpolation; Shell command built from variables; eval or new Function on dynamic input; HTML injected from a variable; Math.random used for a token, code or password; Cookie set without httpOnly / secure / sameSite; JWT verified without pinning algorithms; CORS allows any origin with credentials; Money or irreversible endpoint without an idempotency key; Query in a multi-tenant codebase without a tenant filter nearby; SELECT * in application code; List query without a limit; target="_blank" without rel="noopener"; Dockerfile uses :latest or runs as root; .env file present and not git-ignored; No lockfile committed; HTTP server without a rate limiter in dependencies.

**What is Faultline?**
Faultline is a free, open source command-line tool that audits a codebase for boundary failures: outbound calls without timeouts, retries without backoff, money endpoints without idempotency keys, swallowed errors, SQL and shell commands built from strings, secrets committed in code, cookies without security flags, CORS misconfiguration and queries that forget the tenant. It prints every finding with the file, the line, the evidence and the fix.

**Is Faultline free? Can I use it at work?**
Yes. Running Faultline on any code, commercial or not, is free and creates no obligation. The AGPL-3.0 license only applies if you modify Faultline itself and distribute it or offer it as a service: then your modified source must be published under the same license. Closed modifications are available under a commercial license from the author.

**Does Faultline send my code anywhere?**
No. It runs locally, has zero dependencies, makes no network calls and has no telemetry. It reads your files and prints a report.

**How is Faultline different from ESLint, Semgrep or Snyk?**
ESLint checks style and language usage. Semgrep and Snyk are broad platforms with rule marketplaces, accounts and services. Faultline is one file-tree walk with 22 opinionated rules about the places where systems actually fail in production: timeouts, retries, idempotency, error handling, injection, secrets, auth and tenant isolation. It is meant to run before a human review and in CI, in seconds, with nothing to install.

**How do I run Faultline in CI?**
Add the GitHub Action (uses: thefgxdev/faultline@main with path and fail-on) or run npx github:thefgxdev/faultline . --fail-on high in any pipeline. The process exits with code 1 when a finding is at or above the chosen severity, and can write a Markdown report and JSON output.

**What about false positives?**
The rules are heuristics with context windows, tuned on real codebases and tested against fixtures of good and bad code. When a rule is wrong for your case, silence that line with // faultline-ignore or the path with .faultlineignore; the silence stays visible in code review. Report false positives with the smallest sample that reproduces them and they become test cases.

**Which languages does Faultline support?**
The rule set is JavaScript and TypeScript first (Node.js, Next.js, Express, Fastify, Prisma, Supabase and plain SQL strings), plus Dockerfiles, .env files, package.json and lockfiles. The file matchers already accept Python, Go, PHP and Ruby; rules for those boundaries are on the roadmap.

**Who made Faultline?**
Felipe Guedes, Software Engineer and Systems Architect based in Toledo, Paraná, Brazil, after ten years and 600+ systems built, reviewed or audited in 19 countries. The tool encodes the questions he asks in every software audit.

## NextFoot (football game, in development)
Match simulation, player and team modelling, real-time state and a multiplayer-ready architecture, where latency and consistency are decided by design, not by luck. Built by Felipe Guedes as the hardest system he knows how to make feel simple.
Page: https://fgxdev.com/nextfoot/ · PT-BR: https://fgxdev.com/pt/nextfoot/ · Status: in development, no public build and no release date.
**What is NextFoot?**
NextFoot is a football game built from the engine up by Felipe Guedes: deterministic match simulation, player and team modelling, real-time state and a multiplayer-ready architecture, rendered in WebGL in the browser. It is in development.

**Can I play NextFoot?**
Not yet. There is no public build and no release date. The project page and the author's profiles will announce a playable version when it exists.

**What is the technology behind NextFoot?**
TypeScript, a custom real-time engine with a deterministic simulation, multiplayer netcode with client prediction and server reconciliation, WebGL rendering in the browser, Node.js on the server and PostgreSQL for accounts, seasons and results.

**Who is building NextFoot?**
Felipe Guedes, Software Engineer and Systems Architect in Toledo, Paraná, Brazil, creator of Faultline and founder of ELUCENIA, after 600+ systems built, reviewed or audited in 19 countries.

## Articles (145)
- [SLOs for a five-person team](https://fgxdev.com/articles/slo-for-a-five-person-team/) (2026-09-21; infra, reliability): You do not need an SRE org to have an SLO. You need one number, one window and one rule about what happens when you miss.
- [Shipping is a habit](https://fgxdev.com/articles/shipping-is-a-habit/) (2026-09-19; career, engineering): Nobody decides not to ship. They decide to do one more thing first. How to build the habit that ends that.
- [Designing a design system that survives its designers](https://fgxdev.com/articles/designing-a-design-system-that-survives/) (2026-09-18; fullstack, ux): A design system dies when the people who made it leave. The ones that live encode decisions in tokens and constraints, not in memory.
- [I find the failure nobody finds. Here is the method.](https://fgxdev.com/articles/i-find-the-failure-nobody-finds/) (2026-09-16; audit, career): It is not intuition. It is a repeatable procedure that assumes the system is lying and goes looking for where.
- [Design the failure before the feature](https://fgxdev.com/articles/design-the-failure-before-the-feature/) (2026-09-14; system-design, reliability): The happy path is the easy part. The system is everything that happens when it breaks, and that is what to design first.
- [Testing non-deterministic systems](https://fgxdev.com/articles/testing-nondeterministic-systems/) (2026-09-11; ai, engineering): You cannot assert on an exact string from a model. You can assert on properties, distributions and invariants, and you should.
- [The twelve questions I ask in every architecture review](https://fgxdev.com/articles/the-architecture-review-questions-i-always-ask/) (2026-09-09; architecture, audit): The same twelve questions, in the same order, on every system. They find most of what matters within a day.
- [AI writes the code. You still own the system.](https://fgxdev.com/articles/ai-writes-the-code-you-still-own-the-system/) (2026-09-05; ai, engineering): The model can type faster than you. It cannot answer for what happens at 3 a.m. That part is still yours.
- [The real cost of a retry](https://fgxdev.com/articles/the-cost-of-a-retry/) (2026-09-02; system-design, reliability): Retries add load exactly when the system is weakest. Backoff, jitter, budgets, idempotency and breakers keep them from amplifying.
- [The slowest loop in science is not thinking](https://fgxdev.com/articles/the-slowest-loop-in-science-is-not-thinking/) (2026-08-31; science, ai): Everyone wants AI to make scientists think faster. The time is not lost in thinking. It is lost in waiting, and waiting is engineering.
- [The whiteboard is where the system is actually built](https://fgxdev.com/articles/the-whiteboard-is-where-the-system-is-built/) (2026-08-30; system-design, architecture): The decisions that hurt later are made in the first hour, before any code. Here is what I draw and why.
- [The AI feature nobody asked for](https://fgxdev.com/articles/the-ai-feature-nobody-asked-for/) (2026-08-28; ai, ux, business): The sparkle button was built for the board, not the user. Here is how to tell, and what to build instead.
- [Where business rules should live, and where they end up](https://fgxdev.com/articles/where-business-rules-should-live/) (2026-08-26; architecture, engineering): The rule is written once in the spec and five times in the code. How it scatters, and how to bring it home.
- [The CDN is the cheapest scaling decision you will make](https://fgxdev.com/articles/cdn-is-the-cheapest-scaling/) (2026-08-23; infra, performance): Before adding servers, ask which responses never needed to reach a server at all.
- [Writing the audit report nobody wants to read, so that they do](https://fgxdev.com/articles/the-audit-report-nobody-wants-to-read/) (2026-08-21; audit, career): An audit is only as good as the fixes it causes. Structure, language and ranking decide whether the report gets acted on or filed.
- [Why I keep choosing Next.js for products that have to last](https://fgxdev.com/articles/why-i-keep-choosing-nextjs/) (2026-08-19; fullstack, nextjs): Not because it is popular. Because it lets one team own the whole request path without inventing glue.
- [A latency budget for LLM features](https://fgxdev.com/articles/llm-latency-budget/) (2026-08-15; ai, performance): The model is the slowest dependency you have ever added. Budget for it the way you budget for a database, per feature, per step.
- [Boundaries are the product](https://fgxdev.com/articles/boundaries-are-the-product/) (2026-08-12; architecture, engineering): Features come and go. The boundaries you draw between them are what you will still be paying for in five years.
- [You own the infrastructure whether you like it or not](https://fgxdev.com/articles/you-own-the-infra-whether-you-like-it-or-not/) (2026-08-09; infra, fullstack): Every line of application code runs on decisions you either made or accepted by default. Both are yours.
- [What a latency histogram is trying to tell you](https://fgxdev.com/articles/reading-a-latency-histogram/) (2026-08-05; system-design, observability): Averages hide. Read the shape, then p50, p95 and p99, and learn why fan-out turns everyone else's p99 into your p50.
- [The ORM is fine. Your queries are not.](https://fgxdev.com/articles/the-orm-is-fine-your-queries-are-not/) (2026-08-02; fullstack, data): Every slow database I audit has the same shape: an ORM blamed for queries nobody read. Read the SQL. Fix the pattern.
- [The strangler fig, done honestly](https://fgxdev.com/articles/the-strangler-fig-done-honestly/) (2026-07-29; architecture): The pattern works. What kills it is pretending the old system will die on its own. It will not.
- [Guardrails that do not ruin the product](https://fgxdev.com/articles/guardrails-that-do-not-ruin-the-product/) (2026-07-26; ai, ux): Most guardrails are a refusal bolted onto the end. Good ones are designed into the task so the user rarely meets them.
- [Auditing a system you did not build, without offending the people who did](https://fgxdev.com/articles/auditing-a-system-you-did-not-build/) (2026-07-24; audit, career): An audit that produces resentment produces no fixes. Here is how I deliver hard findings and keep the team on my side.
- [CI that tells you the truth](https://fgxdev.com/articles/ci-that-tells-you-the-truth/) (2026-07-22; infra, engineering): A green build that lies is worse than no build. Here is what it takes to make CI a signal you can act on.
- [Idempotency is a business decision](https://fgxdev.com/articles/idempotency-is-a-business-decision/) (2026-07-21; system-design, engineering): Call it twice, get the same result. Sounds technical. Deciding what "the same" means is where the business signs.
- [The hypothesis loop, and where software can shorten it](https://fgxdev.com/articles/the-hypothesis-loop/) (2026-07-18; science, ai): Science is a loop, not a line. Software should shorten the cheap turns and leave the expensive ones exactly as slow as truth requires.
- [React state that belongs to the server](https://fgxdev.com/articles/react-state-that-belongs-to-the-server/) (2026-07-15; fullstack, nextjs): Most useState calls I audit are holding a copy of the database. Put that state where it lives and the bugs go with it.
- [Hallucination is a system property, not a model bug](https://fgxdev.com/articles/hallucination-is-a-system-property/) (2026-07-11; ai, reliability): The model generates plausible text. Whether plausible becomes false in front of a user depends on the system you built around it.
- [Why most microservices should have been modules](https://fgxdev.com/articles/why-most-microservices-should-be-modules/) (2026-07-08; system-design, architecture): The network boundary is a permanent tax. Four reasons a service earns it, and the signals that yours should have been a module.
- [Say no to the rewrite](https://fgxdev.com/articles/say-no-to-the-rewrite/) (2026-07-06; career, architecture): The rewrite promises a clean slate and delivers a second system chasing the first. Five questions before you approve one.
- [Containers are not isolation](https://fgxdev.com/articles/containers-are-not-isolation/) (2026-07-03; infra, security): A container is a process with a costume. Treat it as a security boundary and you will eventually regret it.
- [Forms are distributed systems](https://fgxdev.com/articles/forms-are-distributed-systems/) (2026-07-01; fullstack, engineering): A form is two machines, an unreliable network and a user who clicks twice. Design it like the distributed system it is.
- [Core Web Vitals are an architecture problem](https://fgxdev.com/articles/core-web-vitals-are-architecture/) (2026-06-30; fullstack, performance): You cannot fix LCP with a plugin. The metrics are measuring your data flow, your boundaries and your deploy.
- [Why a software engineer cares about science](https://fgxdev.com/articles/why-a-software-engineer-cares-about-science/) (2026-06-28; science, career): Science is the oldest system for producing reliable knowledge. An engineer who ignores it is leaving the best design on the table.
- [AI pair programming changed what I put on the whiteboard](https://fgxdev.com/articles/ai-pair-programming-changed-my-whiteboard/) (2026-06-26; ai, system-design): When the code is cheap, the whiteboard stops being about code. It becomes about failure, ownership and invariants.
- [Domain events versus notifications: they are not the same thing](https://fgxdev.com/articles/domain-events-vs-notifications/) (2026-06-24; architecture): One is a fact the business cares about. The other is a poke. Confusing them is how event-driven systems rot.
- [Faith, family and uptime](https://fgxdev.com/articles/faith-family-and-uptime/) (2026-06-21; life): What I hold above my work, and how those constraints made my systems more reliable, not less.
- [Evaluating LLM features like an engineer, not a fan](https://fgxdev.com/articles/evaluating-llm-features-like-an-engineer/) (2026-06-19; ai, audit): If your quality signal is a demo and a feeling, you do not have a feature. You have a hope. Here is how I build evals.
- [Rate limiting without hurting the users you want](https://fgxdev.com/articles/rate-limiting-without-hurting-good-users/) (2026-06-17; system-design): Token bucket, identity over IP, per-plan tiers, shadow mode: how to stop abuse without throwing 429s at paying customers.
- [From papers to questions: what an instrument for research should do](https://fgxdev.com/articles/from-papers-to-questions/) (2026-06-14; science, ai): A summarizer gives you less to read. A research instrument gives you better questions to ask. The difference is the whole product.
- [Postgres is enough, until the day it is not, and how to know that day](https://fgxdev.com/articles/postgres-is-enough-until-it-is-not/) (2026-06-12; infra, data): Most teams leave Postgres too early or too late. The signals that tell you which are measurable.
- [Designing for deletion](https://fgxdev.com/articles/designing-for-deletion/) (2026-06-10; architecture, data): Every system can create a record. Few can delete one correctly. Design the delete path first and the rest gets simpler.
- [Code review is risk review](https://fgxdev.com/articles/code-review-is-risk-review/) (2026-06-08; audit, engineering): Most reviews check whether the code is nice. The question that matters is what breaks, for whom, and how you get it back.
- [TypeScript generics that help, and the ones that hurt](https://fgxdev.com/articles/typescript-generics-that-help-vs-hurt/) (2026-06-05; fullstack, typescript): A generic that relates an input to an output is a gift. A generic that appears once in a signature is a lie the compiler cannot catch.
- [Designing APIs people can misuse safely](https://fgxdev.com/articles/designing-apis-people-can-misuse-safely/) (2026-06-02; system-design, engineering): Clients retry, duplicate, send stale data and call out of order. Design so the ordinary misuse is harmless.
- [What AI cannot audit](https://fgxdev.com/articles/what-ai-cannot-audit/) (2026-05-30; ai, audit): Models are excellent at finding what looks wrong. The failures that matter are the ones that look right, and those still need a person.
- [Multi-tenancy: the decision you cannot undo](https://fgxdev.com/articles/multi-tenancy-the-decision-you-cannot-undo/) (2026-05-27; system-design, architecture): Shared schema, schema per tenant or database per tenant: each is a different set of pains, and switching later means migrating everything.
- [Evidence-first software](https://fgxdev.com/articles/evidence-first-software/) (2026-05-25; science, engineering): Every claim a system makes should be able to say why. Here is how I build software where the evidence comes before the conclusion.
- [Zero-downtime migrations in practice](https://fgxdev.com/articles/zero-downtime-migrations-in-practice/) (2026-05-22; infra, data): The schema change is never the hard part. The lock, the backfill and the old code still running are.
- [The full-stack engineer is a systems engineer](https://fgxdev.com/articles/the-full-stack-engineer-is-a-systems-engineer/) (2026-05-20; fullstack, career): Full stack was never about knowing two languages. It is about owning the failure wherever it happens.
- [What a doctor taught me about systems](https://fgxdev.com/articles/what-a-doctor-taught-me-about-systems/) (2026-05-19; life, system-design): I met my father once, in his clinic. His way of diagnosing patients is how I audit systems today.
- [The human in the loop is a design decision](https://fgxdev.com/articles/the-human-in-the-loop-is-a-design-decision/) (2026-05-15; ai, science): A human in the loop is not a checkbox for the compliance slide. It is an interface, a workflow and a budget you have to design.
- [The shared library trap](https://fgxdev.com/articles/the-shared-library-trap/) (2026-05-13; architecture): The package that was created to avoid duplication is often the tightest coupling in the system. How to tell, and what to do instead.
- [Details are not small](https://fgxdev.com/articles/details-are-not-small/) (2026-05-11; audit, life): A detail is a decision at small scale. The systems that fail, and the people we remember, are made of them.
- [The first three alerts every system needs](https://fgxdev.com/articles/the-first-three-alerts/) (2026-05-08; infra, reliability): Before dashboards, before SLOs, before anything: three alerts that catch most outages and almost never lie.
- [How I read a system I have never seen in one hour](https://fgxdev.com/articles/how-i-read-a-system-in-one-hour/) (2026-05-06; system-design, audit): The audit method I use to understand an unfamiliar system fast: entry points, data, money, and what happens when it is down.
- [Error boundaries, end to end](https://fgxdev.com/articles/error-boundaries-end-to-end/) (2026-05-01; fullstack, reliability): An error boundary is not a React component. It is a decision about where failure stops, made at every layer from the click to the database.
- [What a green build hides](https://fgxdev.com/articles/what-a-green-build-hides/) (2026-04-30; audit, infra): A passing pipeline proves the tests you wrote pass on the machine they ran on. Everything else is faith. Here is what to check.
- [File uploads, done right the first time](https://fgxdev.com/articles/file-uploads-done-right/) (2026-04-28; fullstack, engineering): Never let a file pass through your application server. Sign, upload direct, verify async, and treat every filename as hostile.
- [Observability for LLM applications](https://fgxdev.com/articles/observability-for-llm-apps/) (2026-04-24; ai, observability): Logs and latency are not enough. You need the prompt, the output, the cost and the quality per request, and the ability to replay it.
- [Architecture decision records that actually get read](https://fgxdev.com/articles/architecture-decision-records-that-get-read/) (2026-04-22; architecture, engineering): Most ADRs are written once and never opened again. Here is the format and the discipline that make them survive.
- [Self-taught is not alone-taught](https://fgxdev.com/articles/self-taught-is-not-alone-taught/) (2026-04-22; career): I never finished a degree, but I was never alone. How to find teachers when nobody assigns you one.
- [Data provenance for scientists, explained by an engineer](https://fgxdev.com/articles/data-provenance-for-scientists/) (2026-04-18; science, data): A number you cannot trace is an opinion with decimals. What provenance means and how to build it without a PhD in databases.
- [Streaming UI and what it costs the backend](https://fgxdev.com/articles/streaming-ui-and-what-it-costs-the-backend/) (2026-04-15; fullstack, nextjs): Streaming makes the page feel fast. It also holds connections open, fans out queries and hides slow paths. Budget for it.
- [When not to use a language model](https://fgxdev.com/articles/when-not-to-use-a-language-model/) (2026-04-11; ai, system-design): A language model is a component with a cost, a latency and an error rate. Half the places I see one, a regex would have won.
- [Designing for the slow dependency, not the dead one](https://fgxdev.com/articles/designing-for-the-slow-dependency/) (2026-04-09; system-design, reliability): Dead dependencies fail fast. Slow ones fill your pools and take you down. Bulkheads, deadlines, fallbacks and p99.
- [Structured logs or nothing](https://fgxdev.com/articles/structured-logs-or-nothing/) (2026-04-05; infra, observability): A log line you cannot query is a log line you will read once, during an incident, too late.
- [The modular monolith in practice](https://fgxdev.com/articles/modular-monolith-in-practice/) (2026-04-01; architecture): One deploy unit, hard internal boundaries. What it looks like in a real TypeScript codebase, and where teams cheat.
- [The hidden cost of every dependency you add](https://fgxdev.com/articles/the-hidden-cost-of-a-dependency/) (2026-03-31; fullstack, audit): The install is free. The transitive tree, the upgrade cadence, the bundle weight and the supply chain risk are not.
- [The ethics of building tools for medicine when you are not a doctor](https://fgxdev.com/articles/the-ethics-of-building-tools-for-medicine/) (2026-03-28; science, life): I am not a physician. I build tools that physicians and scientists will use. Here is the line I draw and why.
- [When to add a message broker, and when you are avoiding a decision](https://fgxdev.com/articles/when-to-add-a-message-broker/) (2026-03-25; system-design): What a broker buys, what it costs, and the tell that you are using a queue to avoid deciding who owns the data.
- [Prompt injection is input validation you forgot](https://fgxdev.com/articles/prompt-injection-is-input-validation/) (2026-03-20; ai, security): We solved SQL injection by separating code from data. Prompt injection is the same lesson in a system that cannot fully separate them.
- [Types at the edges: validate once, trust everywhere](https://fgxdev.com/articles/types-at-the-edges/) (2026-03-18; fullstack, typescript): TypeScript types vanish at runtime. Put a real check at every edge, then let the compiler carry the proof inward.
- [The first thing I check in any codebase](https://fgxdev.com/articles/the-first-thing-i-check-in-any-codebase/) (2026-03-15; audit, engineering): Before the architecture, before the tests, before the README: I find every place the data is written and count them.
- [The cloud cost nobody budgets for](https://fgxdev.com/articles/the-cost-of-cloud-nobody-budgets/) (2026-03-13; infra, business): Compute is the line everyone watches. The bill grows in the lines nobody reads.
- [Reversibility as an architecture goal](https://fgxdev.com/articles/reversibility-as-an-architecture-goal/) (2026-03-11; architecture, system-design): The best architecture decision is the one you can undo in a sprint. Optimize for that before optimizing for anything else.
- [Building world-class systems from a small city in Paraná](https://fgxdev.com/articles/building-from-a-small-city/) (2026-03-08; career, life): Location matters. Here is what you have to do differently when you are never in the room.
- [The prompt is not the spec](https://fgxdev.com/articles/the-prompt-is-not-the-spec/) (2026-03-06; ai, engineering): A prompt tells the model what to do today. A spec tells everyone what correct means. Teams keep confusing the two.
- [Back-pressure is a feature, not a bug](https://fgxdev.com/articles/back-pressure-is-a-feature/) (2026-03-03; system-design, reliability): A system that says "not now" is healthier than one that says yes to everything and falls over. Build the refusal path.
- [AI and the end of boilerplate, and what fills the space](https://fgxdev.com/articles/ai-and-the-end-of-boilerplate/) (2026-02-28; ai, career): Generating code is now cheap. The scarce skills moved to specification, verification and taste, and the career moved with them.
- [DNS TTLs and other small things that bite at 3 a.m.](https://fgxdev.com/articles/dns-ttl-and-other-things-that-bite/) (2026-02-27; infra): The outages that hurt most are rarely architectural. They are a number someone set once and forgot.
- [State machines for everything that matters](https://fgxdev.com/articles/state-machines-for-everything-that-matters/) (2026-02-24; system-design, engineering): Boolean flag soup hides contradictions. Explicit states, a transition table and a transitions log make bugs and reports obvious.
- [What I look for in an engineer](https://fgxdev.com/articles/what-i-look-for-in-an-engineer/) (2026-02-22; career): Not the stack, not the years. Five habits that show up in the first hour and predict everything after.
- [The deploy is part of the design](https://fgxdev.com/articles/the-deploy-is-part-of-the-design/) (2026-02-20; infra, system-design): If you cannot describe how a change reaches production safely, the design is not finished.
- [The bug is always in the boundary](https://fgxdev.com/articles/the-bug-is-always-in-the-boundary/) (2026-02-19; audit, architecture): Inside a module, code is consistent with itself. Bugs live where two things with different assumptions meet.
- [TypeScript as a design tool, not a linter](https://fgxdev.com/articles/typescript-as-a-design-tool/) (2026-02-17; fullstack, typescript): If your types only catch typos, you are using a tenth of the tool. Types are where I design the system first.
- [How I review code a model wrote](https://fgxdev.com/articles/reviewing-ai-generated-code/) (2026-02-13; ai, audit): Same standards as any pull request, but the bugs live in different places. Here is where I look.
- [Eventual consistency, explained to the product team](https://fgxdev.com/articles/eventual-consistency-explained-to-the-product-team/) (2026-02-11; system-design): Why the order shows up three seconds later, which flows must never lag, and how to design a UI that tells the truth.
- [Cardiovascular data is a systems problem](https://fgxdev.com/articles/cardiovascular-data-is-a-systems-problem/) (2026-02-08; science, data): The heart produces more kinds of data than almost any organ. Making them agree is not a medical problem. It is an integration problem.
- [The edge runtime: when it helps and when it just moves the problem](https://fgxdev.com/articles/edge-runtime-when-and-when-not/) (2026-02-05; fullstack, nextjs): Compute near the user is only fast if the data is near the compute. Otherwise you have added a round trip to every query.
- [Reading legacy code like an archaeologist](https://fgxdev.com/articles/reading-legacy-code-like-an-archaeologist/) (2026-02-03; architecture, audit): Legacy code is not bad code. It is a record of decisions under pressure. Learn to read the layers before you dig.
- [Agents need boundaries too](https://fgxdev.com/articles/agents-need-boundaries-too/) (2026-01-31; ai, architecture): An agent is a loop with permissions. Every rule I apply to services applies to it, with a larger blast radius.
- [The API route that became a monolith](https://fgxdev.com/articles/the-api-route-that-became-a-monolith/) (2026-01-29; fullstack, nextjs, architecture): It started as one handler. Two years later it is a 900-line file that nobody dares to touch. Here is how to prevent that.
- [Caching is a consistency decision in disguise](https://fgxdev.com/articles/caching-is-a-consistency-decision/) (2026-01-27; system-design, architecture): A cache is a copy, and every copy forces you to decide how stale a user is allowed to see the world.
- [Validation is not a phase](https://fgxdev.com/articles/validation-is-not-a-phase/) (2026-01-24; science, engineering): Software teams learned that testing at the end does not work. Science tools need the same lesson: validate every step, or it is a draft.
- [Load testing the right thing](https://fgxdev.com/articles/load-testing-the-right-thing/) (2026-01-22; infra, performance): Most load tests measure how fast the server returns a cached homepage. Production fails somewhere else.
- [Contracts before code](https://fgxdev.com/articles/contracts-before-code/) (2026-01-20; architecture, engineering): Write the interface, the schema and the failure cases before the first implementation line. It is the cheapest design review you will get.
- [A security review you can do in an afternoon](https://fgxdev.com/articles/security-review-in-an-afternoon/) (2026-01-17; audit, security): Not a penetration test. The seven checks that find most of what actually gets exploited, in four hours, with tools you already have.
- [WebSockets, SSE or polling: a decision table](https://fgxdev.com/articles/websockets-vs-sse-vs-polling/) (2026-01-15; fullstack, system-design): Three ways to get live data to a browser. The right one depends on direction, scale and your hosting, not on which sounds modern.
- [The outbox pattern in plain words](https://fgxdev.com/articles/the-outbox-pattern-in-plain-words/) (2026-01-13; system-design, data): Commit the event with the data, let a relay publish it, make consumers idempotent. The dual-write problem, solved in plain words.
- [Research is a system with a throughput problem](https://fgxdev.com/articles/research-is-a-system-with-a-throughput-problem/) (2026-01-10; science, system-design): Scientists are not slow. The pipeline around them is. Here is how a systems engineer reads a research lab.
- [Blue-green, canary and the honest rollback](https://fgxdev.com/articles/blue-green-canary-and-the-honest-rollback/) (2026-01-08; infra): Deployment strategies are only as good as the rollback they actually allow. Most teams overestimate theirs.
- [Hexagonal architecture without the ceremony](https://fgxdev.com/articles/hexagonal-without-the-ceremony/) (2026-01-06; architecture): Ports and adapters is one good idea buried under a pile of folders. Keep the idea, drop the pile.
- [The generalist advantage](https://fgxdev.com/articles/the-generalist-advantage/) (2026-01-05; career, fullstack): Failures live at the boundaries between layers, and the generalist is the one who can see the seam.
- [Embeddings are not magic. They are a compression of your data.](https://fgxdev.com/articles/embeddings-are-not-magic/) (2026-01-03; ai, data): An embedding is a lossy summary chosen by someone else's training data. Treat it like a compression format, not an oracle.
- [Server Components change where the boundary is](https://fgxdev.com/articles/server-components-change-where-the-boundary-is/) (2025-12-30; fullstack, nextjs, architecture): The old boundary was the API. The new one is a directive at the top of a file. Most teams have not noticed.
- [The staging environment lie](https://fgxdev.com/articles/the-staging-environment-lie/) (2025-12-27; infra, engineering): Staging proves the code runs. It almost never proves the code runs in production, and pretending otherwise is expensive.
- [What a new service really costs](https://fgxdev.com/articles/the-cost-of-a-new-service/) (2025-12-23; architecture, system-design): The code is the cheap part. This is the invoice that comes with every box you add to the diagram.
- [The model will change. The interface should not.](https://fgxdev.com/articles/the-model-will-change-the-interface-should-not/) (2025-12-20; ai, architecture): Design the boundary around the model so that swapping providers, versions or prompts is a config change, not a rewrite.
- [Why I still write SQL by hand](https://fgxdev.com/articles/why-i-still-write-sql-by-hand/) (2025-12-18; fullstack, data): The database is the most capable engine in your stack. A query builder hides that capability. I write the queries that matter myself.
- [A graceful degradation checklist for product teams](https://fgxdev.com/articles/graceful-degradation-checklist/) (2025-12-16; system-design, reliability): Decide on purpose what users see when recommendations, search, payments or the database fail. A checklist for product teams.
- [What clinicians taught me about requirements](https://fgxdev.com/articles/what-clinicians-taught-me-about-requirements/) (2025-12-14; science, career): I thought I knew how to gather requirements after hundreds of projects. Then I sat with people whose mistakes have a pulse.
- [Secrets management for small teams that will grow](https://fgxdev.com/articles/secrets-management-for-small-teams/) (2025-12-11; infra, security): The .env file is fine on day one and a liability on day ninety. Here is the path that does not require a rewrite.
- [The database is not your integration layer](https://fgxdev.com/articles/the-database-is-not-your-integration-layer/) (2025-12-09; architecture, data): Two systems sharing a database are one system with two deploy pipelines and no contract. Here is how to get out.
- [Read the error handling first](https://fgxdev.com/articles/reading-the-error-handling-first/) (2025-12-08; audit, reliability): Catch blocks are where a team wrote down what it fears and what it chose to ignore. Read them before anything else.
- [The cost of a token in production](https://fgxdev.com/articles/the-cost-of-a-token-in-production/) (2025-12-06; ai, business): The price per token is the smallest part of the bill. Context, retries and loops are where the money actually goes.
- [Auth is not a library decision](https://fgxdev.com/articles/auth-is-not-a-library-decision/) (2025-12-04; fullstack, security): Pick the library last. First decide who the identity belongs to, where the session lives and what happens when it is revoked.
- [The hot partition problem and why sharding does not save you](https://fgxdev.com/articles/the-hot-partition-problem/) (2025-12-02; system-design, data): Sharding spreads keys, not load. When one key is hot by itself, you need a different toolbox.
- [The year I lost every contract](https://fgxdev.com/articles/the-year-i-lost-every-contract/) (2025-12-01; career, life): In 2020 every contract vanished in weeks. What I rebuilt had a different shape, and the shape is the useful part.
- [Fine-tuning, retrieval or prompting: a decision I make weekly](https://fgxdev.com/articles/fine-tuning-vs-retrieval-vs-prompting/) (2025-11-29; ai): Three tools, three kinds of problems. Most teams pick by excitement. I pick by what changes and how often.
- [A post-mortem template that produces change](https://fgxdev.com/articles/an-incident-postmortem-template/) (2025-11-27; infra, reliability): Most post-mortems are well-written and change nothing. The template decides which kind you write.
- [The monolith is not the problem, the coupling is](https://fgxdev.com/articles/the-monolith-is-not-the-problem/) (2025-11-25; architecture): Splitting a tangled monolith into services gives you a tangled distributed system. Fix the coupling first.
- [Six hundred projects later: what repeats](https://fgxdev.com/articles/six-hundred-projects-later/) (2025-11-22; audit, career): After 600+ projects built, reviewed or audited, the failures stopped surprising me. Here is the short list that keeps coming back.
- [Feature flags as architecture](https://fgxdev.com/articles/feature-flags-as-architecture/) (2025-11-20; fullstack, engineering): A flag is a branch in your system that lives in production. Treat it like one, or it becomes the bug nobody can reproduce.
- [The queue you did not know you had](https://fgxdev.com/articles/the-queue-you-did-not-know-you-had/) (2025-11-18; system-design): Your diagram shows one queue. Your system has twenty. Little's law explains why they all fill at the same time.
- [Reproducibility is an engineering problem](https://fgxdev.com/articles/reproducibility-is-an-engineering-problem/) (2025-11-15; science, engineering): 'It worked on my laptop' is not a scientific result. The tools to fix that already exist, and they are boring.
- [Observability is a product feature](https://fgxdev.com/articles/observability-is-a-product-feature/) (2025-11-13; infra, observability): The ability to answer "what happened to this user" is worth more than most items on your roadmap.
- [API versioning is a relationship, not a number](https://fgxdev.com/articles/api-versioning-is-a-relationship/) (2025-11-11; architecture, engineering): The version in the URL is the least important part. What matters is who depends on you and what you owe them.
- [RAG is a data pipeline with a language model at the end](https://fgxdev.com/articles/rag-is-a-data-pipeline/) (2025-11-08; ai, system-design): Most RAG failures I audit are ingestion and retrieval bugs wearing an AI costume. Fix the pipeline, then worry about the prompt.
- [Caching in Next.js without surprises](https://fgxdev.com/articles/caching-in-nextjs-without-surprises/) (2025-11-06; fullstack, nextjs): Four cache layers, one rule: never cache what you cannot name, and never name what you cannot invalidate.
- [Exactly-once is a promise nobody keeps](https://fgxdev.com/articles/exactly-once-is-a-promise-nobody-keeps/) (2025-11-04; system-design, engineering): Delivery and processing are different promises. At-least-once plus an idempotent consumer is the guarantee you actually get.
- [Strict mode is the cheapest code review you will ever get](https://fgxdev.com/articles/strict-mode-is-the-cheapest-review/) (2025-10-30; fullstack, typescript): A reviewer who reads every line, on every keystroke, never tires and has no ego. It costs one line in tsconfig.
- [Capacity planning on a napkin](https://fgxdev.com/articles/capacity-planning-on-a-napkin/) (2025-10-28; system-design): Back-of-the-envelope math that tells you whether you are building for 10 rps or 10,000, and which number you are wrong about.
- [Small models, big leverage](https://fgxdev.com/articles/small-models-big-leverage/) (2025-10-25; ai, system-design): The frontier model is the wrong default. Most work in a real pipeline is narrow, repetitive and cheap to get right with a small model.
- [A TypeScript monorepo that stays fast after year two](https://fgxdev.com/articles/a-typescript-monorepo-that-stays-fast/) (2025-10-23; fullstack, typescript): Monorepos do not get slow because they are big. They get slow because nobody drew the dependency graph on purpose.
- [Conway's law is a tool, not a curse](https://fgxdev.com/articles/conways-law-is-a-tool/) (2025-10-21; architecture, career): Your system will mirror your org chart whether you like it or not. So draw the org chart on purpose.
- [The pull request that looks fine](https://fgxdev.com/articles/the-pr-that-looks-fine/) (2025-10-19; audit, engineering): Small diff, green tests, clear description, quick approval. Here is the anatomy of the change that took production down anyway.
- [Backups you have never restored are hypotheses](https://fgxdev.com/articles/backups-you-have-never-restored/) (2025-10-17; infra, reliability): A backup is a claim about the future. Only a restore turns it into a fact.
- [Schema evolution without downtime](https://fgxdev.com/articles/schema-evolution-without-downtime/) (2025-10-15; system-design, data): Expand and contract, batched backfills, lock-aware migrations and feature-flagged cutovers: how to change a schema while it runs.
- [Structured outputs are contracts](https://fgxdev.com/articles/structured-outputs-are-contracts/) (2025-10-11; ai, engineering): A schema turns a model from a text generator into a component you can integrate. Treat it with the seriousness of an API.
- [Timeouts are the cheapest resilience you will ever buy](https://fgxdev.com/articles/timeouts-are-the-cheapest-resilience/) (2025-10-09; system-design, reliability): No timeout means infinite. Here is how I set connect, read and total budgets so one slow dependency cannot take the whole system down.
- [Open science needs boring infrastructure](https://fgxdev.com/articles/open-science-needs-boring-infrastructure/) (2025-10-05; science, infra): Open science does not fail on ideals. It fails on storage, identifiers, uptime and the unpaid person keeping the server alive.
- [Technical debt is a loan, and every loan has a name on it](https://fgxdev.com/articles/technical-debt-is-a-loan-with-a-name/) (2025-10-02; architecture, career): Debt is not the shortcut. It is the shortcut without an owner, a term and a payment date. Fix the metaphor and the backlog moves.
- [From the print shop to the whiteboard](https://fgxdev.com/articles/from-the-print-shop-to-the-whiteboard/) (2025-10-01; career, life): Vinyl cutting, electronics repair and construction taught me the three habits I still use to design systems.

## Links
- github: https://github.com/thefgxdev
- linkedin: https://www.linkedin.com/in/fgxdev
- x: https://x.com/thefgxdev
- instagram: https://instagram.com/eufeguedes
- memorial: https://pedromorettiguedes.com.br/
- email: contato@fgxdev.com
- Portuguese (Brazil) version of the site: https://fgxdev.com/pt/
- Portuguese (Brazil) version of this file: https://fgxdev.com/llms-pt-br.txt
- Father's memorial (Dr. Pedro Moretti Guedes, physician, 1935–2010): https://pedromorettiguedes.com.br/