Roll back a config change without a deploy

11:04 AM. A teammate updates kv/config:rate_limits to a lower value. By 11:05, support is on fire: every fourth request is a 429.

You don't redeploy. You don't read git log. You don't try to remember the old values from a Slack message. You POST kv/config:rate_limits/rollback and the previous value comes back. The KV store keeps the full change history; rollback walks one step backward and writes the prior state.

Then, at your leisure, you GET kv/config:rate_limits/history and read the diff to see what was actually changed. You bring it up in standup. The fix conversation happens after the page is fixed, not before.

Configuration treated as code is heroic but slow. Configuration treated as a versioned KV store is just fast.

You shipped a regression at 11:04. You reverted it at 11:05. Both via HTTP.