What is graceful shutdown in Node.js and how do you implement it?

Graceful shutdown is the process of cleanly stopping a Node.js server by: (1) stopping acceptance of new connections, (2) waiting for in-flight requests to complete, (3) closing database connections, message queue connections, and other resources. Without it, mid-flight requests are killed, causing errors for users and potential data corruption. Implementation: listen to shutdown signals — process.on("SIGTERM", shutdown) and process.on("SIGINT", shutdown) (Ctrl+C). In the shutdown handler: (1) call server.close(callback) — stops accepting new connections, waits for active connections; (2) close database pools: await pool.end();; (3) close Redis clients; (4) flush log buffers; (5) call process.exit(0) after cleanup. Add a timeout (e.g., 30s) to force exit if cleanup hangs: setTimeout(() => process.exit(1), 30000);. In Kubernetes, containers receive SIGTERM before SIGKILL (default 30s grace period) — configure this to allow enough time for your app's shutdown. Libraries like terminus simplify health checks and graceful shutdown for Express/Fastify.