Lesson 19 — Exponential backoff + jitter

Add randomness to retries

If 1,000 clients fail at the same moment and all retry after exactly 100 ms, they hit the server again at the same moment — a thundering herd. Jitter adds a random part to each wait, so retries spread out. With "full jitter", the wait is a random number between 0 and the backoff value.

To make the output checkable, random here is a fake that returns fixed numbers; real code uses Math.random().

Why it matters: jitter is what stops retries from turning a small outage into a big one.