Retry Patterns That Work: Exponential Backoff, Jitter, and Dead Letter Queues (2026)

#backend #typescript #architecture #reliability

Network call fails. You retry immediately. It fails again. You retry in a tight loop. You DDoS your own service.

Exponential Backoff

Wait longer between each retry: 1s, 2s, 4s, 8s, 16s.

async function retry<T>(fn: () => Promise<T>, maxRetries = 5): Promise<T> {
  for (let i = 0; i < maxRetries; i++) {
    try { return await fn(); }
    catch (err) {
      if (i === maxRetries - 1) throw err;
      const delay = Math.min(1000 * Math.pow(2, i), 30000);
      const jitter = delay * (0.5 + Math.random() * 0.5);
      await new Promise(r => setTimeout(r, jitter));
    }
  }
}

Why Jitter Matters

Without jitter, 1000 clients all retry at the same exponential intervals. They stampede the server simultaneously. Jitter randomizes the retry time so clients spread out naturally.

What NOT to Retry

Retry: 429 (rate limit), 503 (overloaded), timeout, connection refused.
Do NOT retry: 400 (bad request), 401 (unauthorized), 404 (not found), 422 (validation error). These will always fail.