Building a RAG API in Node.js: the setup I’d ship in 2026
Build a production RAG API in Node.js with OpenAI embeddings, pgvector, chunking, metadata filters, streaming answers, citations, and cost controls.
Common Node.js errors · quick reference
All error fixes →| Error | What it means / fix |
|---|---|
| UnhandledPromise | Express.js async error handling that actually works in 2026 Express.js async error handling that actually works in 2026: Express 5 native catching, the express-async-errors patch for legacy apps, typed error classes, and the Sentry integration that survives a bad deploy. |
| MODULE_NOT_FOUND | Fix “Cannot find module” in Node.js (CommonJS, ES modules, TypeScript) Fix Cannot find module in Node.js: CommonJS vs ESM resolution rules, TypeScript path aliases at runtime, file case-sensitivity, monorepo workspace pitfalls, and the diagnostic tree I hand new engineers. |
| EADDRINUSE | Fix EADDRINUSE: address already in use in Node.js (Mac, Linux, Windows) Fix EADDRINUSE: address already in use in Node.js on Mac, Linux, and Windows. The kill commands per OS, the TIME_WAIT trap, graceful shutdown, and how to stop it from coming back. |
Tutorials & how-tos
All tutorials →
WebSockets in Node.js with Socket.io: a real-time chat that scales past one server
GraphQL in Node.js with Apollo Server in 2026: the setup I’d ship to a paying client
Cron jobs in Node.js: the scheduling patterns I trust in production
Testing a Node.js API in 2026: Jest, Vitest, and the suite I actually trust
Comparisons & benchmarks
All comparisons →
Sequelize vs Prisma vs TypeORM in 2026: the Node.js ORM benchmark and the pick I’d make
I've shipped APIs on all three. Sequelize from 2017 to 2020 on a payments API that's still in production. TypeORM through 2021 on a logistics dashboard, where the migration generator broke twice and burned a sprint each time.…
Performance & Architecture
All recipes →
Node.js
Recipe
OpenTelemetry in Node.js: production traces that help
OpenTelemetry in Node.js with HTTP, Express or Fastify, pg, Prisma, Redis, request IDs, trace propagation, sampling, and the incident view that matters.
Node.js
Recipe
PostgreSQL connection pooling in Node.js: the bug that shows up at scale
PostgreSQL connection pooling in Node.js with pg, Prisma, PgBouncer, serverless limits, transaction pooling traps, and the dashboard I check first.
Docker
Recipe
Node.js microservices architecture: the patterns that actually held in production
I helped a logistics startup split a Node.js monolith into seven services in 2022 and watched them spend the next eight months untangling a distributed monolith. The services…
Express
Recipe
Node.js API security in 2026: the checklist I run before pushing to prod
I leaked a logistics company’s internal API for eleven days. Not a customer-facing one — an admin endpoint that returned every shipment’s tracking number, recipient address, and carrier…
Node.js
Recipe
Node.js cluster vs worker threads: which one when (and the trap I fell into)
I had a Node.js video-processing API throwing 503s every time someone uploaded a 4K clip. The default fix everyone reaches for — cluster.fork() across cores — actually made…
Node.js
Recipe
Node.js performance optimization in 2026: the checklist I run before every launch
I rewrote a logistics-analytics Node.js API last summer that was averaging 870 ms p99 on a single endpoint. After two days of clinic.js and four targeted changes (none…
