expressjs-docs

Express questions are easy to answer from stale memory or outdated Express 4 patterns. Use this skill to ground answers in the official Express.js documentation and return the closest authoritative page instead of generic Node.js HTTP advice.

When to Use

Use this skill when the request is about:

• Express concepts, middleware model, routing, and application structure
• express(), the application object, request/response objects, and Router
• Route paths, parameters, handlers, and HTTP method routing
• Writing and using middleware, including error-handling middleware
• Static files, template engines, and serving assets
• Error handling, debugging, and working behind proxies
• Database integration patterns documented by Express
• Express 5 migration, performance best practices, security, and graceful shutdown
• Official Express middleware packages (body-parser, cors, session, etc.)

Do not use this skill for:

• NestJS abstractions built on Express. Use nestjs-docs instead.
• Fastify-specific APIs or plugin architecture. Use fastify-docs instead.
• Third-party middleware behavior not covered by Express docs unless the question is about general Express middleware integration.

Workflow

1. Classify the request

Decide which bucket the question belongs to before searching:

• Getting started and installation
• Routing and route handlers
• Middleware (application-level and router-level)
• Request and response APIs
• Error handling and debugging
• Templates, static files, and proxies
• Migration (Express 4 to 5)
• Performance, security, and production operations
• Official middleware reference

If you need a quick starting point, load references/topic-map.md and jump to the closest section.

2. Search official Express docs first

• Treat expressjs.com/en as the source of truth for Express.js.
• Prefer pages under https://expressjs.com/en/.
• Default to Express 5.x docs unless the user explicitly needs Express 4.
• Search with the user's exact terms plus focused Express phrases such as app.use, next(err), Router, res.send, or path-to-regexp.
• When multiple pages are plausible, compare 2-3 candidate pages and pick the one that most directly answers the user's question.
• For Express 5 breaking changes, check the migration guide before answering from Express 4 knowledge.