Node.js Best Practices
Node's single-threaded, event-loop model rewards certain patterns and punishes others in ways that aren't always obvious until an application is under real load.
Last updated 2026-09-08
Never block the event loop with synchronous, CPU-heavy work
A long-running synchronous computation (heavy JSON parsing, image processing, complex regex) blocks Node's single thread entirely, freezing every other concurrent request until it finishes. Offload genuinely CPU-heavy work to a worker thread or a separate service.
Handle uncaught exceptions and unhandled rejections explicitly
An uncaught exception in Node can crash the entire process, taking down every in-flight request, not just the one that errored. Explicit process-level handlers (and, more importantly, proper try/catch throughout the codebase) prevent this.
Use environment variables for configuration, never hardcoded secrets
Database credentials, API keys, and environment-specific settings belong in environment variables (loaded via something like dotenv locally), never committed directly in source code.
Set appropriate resource limits and timeouts
A request with no timeout can hang indefinitely, tying up a connection and resources. Set explicit timeouts on outbound HTTP calls and database queries rather than relying on defaults that may be too generous or absent entirely.
Use a process manager or orchestrator for production, not a bare node command
A raw node process has no automatic restart on crash. A process manager (PM2) or container orchestrator (Kubernetes) provides restart-on-failure, log management, and (for orchestrators) horizontal scaling that a bare process lacks.
Common Mistakes to Avoid
- ⚠Synchronous, CPU-heavy operations blocking the event loop and stalling all concurrent requests
- ⚠No handling for uncaught exceptions, letting a single unhandled error crash the whole process
- ⚠Hardcoded secrets in source code instead of environment variables
- ⚠No timeout on outbound requests or database queries, allowing a single hang to tie up resources indefinitely
- ⚠Running a bare node process in production with no restart-on-crash mechanism
Frequently Asked Questions
Is Node.js good for CPU-intensive workloads?
Not natively — its single-threaded event loop is optimized for I/O-bound work (handling many concurrent network requests), not CPU-bound computation. Genuinely CPU-heavy work should go to worker threads, a separate service, or a different runtime better suited to it.
Should I always use async/non-blocking APIs over sync ones?
Yes, in any code path handling concurrent requests — Node's synchronous file/crypto APIs exist mainly for startup scripts and CLI tools where blocking briefly doesn't affect other work, not for request-handling code.