Interactive teaching simulator for consistent hashing. Servers and keys are placed on a circular hash ring; each key is owned by the first server reached walking clockwise. Add or remove servers to see how few keys move.

How to read this Every server (large dot) and every key (small dot) is placed on the ring by hashing its name. To find a key's server, walk clockwise from the key until you hit one — that's the owner. The dashed lines are those clockwise walks. Try the demo button below.
hash 0 ¼ ½ ¾ clockwise → ring state 3 · 6 servers · keys
Click a server to remove it · hover anything to inspect
Why this matters With naive sharding (hash(key) % N), changing N reshuffles almost every key. With consistent hashing, only the keys in the affected arc move — usually a small fraction. Try removing a server to see this in action.