Request Timeout Handling in Node.js APIs

Requests to slow upstream services hold connections open indefinitely, exhausting server resources. Clients get no feedback and eventually time out on their end.

Set explicit timeouts at the HTTP server level and on upstream fetch calls.

import http from 'node:http';

const server = http.createServer(app);
server.requestTimeout = 30_000; // 30s
server.headersTimeout = 60_000;

// Upstream fetch with AbortController
async function fetchWithTimeout(url: string, ms: number): Promise<Response> {
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), ms);
  try {
    return await fetch(url, { signal: controller.signal });
  } catch (e) {
    if (e instanceof Error && e.name === 'AbortError') {
      throw new Error(`Upstream timeout after ${ms}ms`);
    }
    throw e;
  } finally {
    clearTimeout(timer);
  }
}

// Per-route timeout middleware
function withTimeout(ms: number): RequestHandler {
  return (req, res, next) => {
    const timer = setTimeout(() => {
      if (!res.headersSent) {
        res.status(503).json({ error: 'Request timeout' });
      }
    }, ms);
    res.on('finish', () => clearTimeout(timer));
    next();
  };
}

Without timeouts, slow upstream services cascade into server resource exhaustion. Each pending request holds an open socket and memory even though Node.js is non-blocking.