Node.js Backend Development

Express is in maintenance mode and has been since 2023. New Node.js APIs should default to Fastify, Hono, or — if you are deploying to the edge — the framework's native HTTP layer. Fastify is consistently 2–3× faster than Express at the same workload, ships with first-class schema validation, and has a meaningfully better TypeScript story.

The migration from Express to Fastify is well-trodden territory. Most route handlers translate one-to-one, middleware maps cleanly to plugins, and the performance lift typically pays for the migration within a single quarter on a moderately-sized API.

Node's single-threaded event loop hides a lot of pathology until it doesn't. Install OpenTelemetry with auto-instrumentation from the first deploy. Track event loop lag, garbage collection pauses, and async resource creation rates as first-class metrics alongside HTTP latency.

The most common production incident pattern we debug in Node services is event loop saturation caused by synchronous JSON parsing of large payloads or by unbounded promise concurrency. Both are invisible without instrumentation and obvious with it.

The single biggest performance lever in any Node.js API is the database access layer. Use a thin query builder (Kysely, Drizzle) rather than an ORM unless your team is unusually disciplined about ORM N+1 patterns. Connection pooling sized to the actual concurrency of your runtime — not the default of 10 — is the second biggest lever.

Read replicas, read-after-write consistency strategies, and CQRS-style read models become relevant above ~1k QPS. Below that, a properly indexed single Postgres with PgBouncer in front comfortably handles the load.