Detect and Fix Memory Leaks in Your Node.js Application with Claude

Memory leaks in Node.js are painful to diagnose — heap snapshots are verbose, and the root cause is rarely obvious. Claude can help you read the evidence and trace it to the source.

Take a heap snapshot, then hand it to Claude:

# Generate a snapshot (or use --inspect and Chrome DevTools)
node --expose-gc -e "
  const v8 = require('v8');
  // ... your app startup
  v8.writeHeapSnapshot();
"

claude "Read this heap snapshot summary and identify the top object types by retained size. Which ones look like leak candidates and why?"

For leaks in long-running servers, ask Claude to review your event listener and timer patterns — the most common culprits:

claude "Review the server code in src/server.ts and src/middleware/. Look for missing removeEventListener calls, setInterval without clearInterval, and closures that hold references to large objects or request/response objects."

Claude spots patterns like attaching listeners inside request handlers without cleanup, caches that grow without eviction, and streams that never call .destroy().

When you've found the leak, ask Claude to write a memory regression test:

// Claude can help you write tests like this
it('does not leak memory across requests', async () => {
  const before = process.memoryUsage().heapUsed;
  for (let i = 0; i < 1000; i++) await makeRequest();
  global.gc?.();
  const after = process.memoryUsage().heapUsed;
  expect(after - before).toBeLessThan(5 * 1024 * 1024); // < 5MB growth
});

Don't stare at heap flamegraphs alone — Claude can read the evidence and point you at the line that's leaking.