Comparison
Deprecation windowvsSunsetting
Deprecation window
you announce the endpoint is going away, keep it running for six months, and watch the traffic to find out who is still on it.
The published period between announcing a removal and performing it. Its real job is instrumentation: you cannot retire anything you cannot measure usage of, per caller. Deprecating without per-client traffic attribution means the window ends and you still cannot safely turn it off.
Full entry →Sunsetting
the replacement went live a year ago and the old service is still running because nobody proved it was idle.
The deliberate process of turning something off: announcing it, migrating remaining users, and deleting it. It is the step that converts a migration from a cost into a saving, and it is routinely skipped because it delivers nothing visible. The technique that actually works is to make the old system prove it is unused — turn it off for an hour, watch what screams — rather than to wait for certainty that will never arrive.
Full entry →