API versioning
Also called: Backward compatibility
Keeping several versions of an API (such as /v1 and /v2) so old apps keep working after breaking changes.
Definition
Removing or renaming fields, changing types or making a field required are breaking changes, so they go into a new version while the old one keeps working for apps that haven't updated. Testers run the old version's tests on every release and try the oldest supported app version against the new back end.
In practice
The 2025 FoodDash app still calls /v1/orders after /v2 renames "total" to "amount"; v1 must keep returning "total".
Learn it in context
Lessons that use this term.
Related terms
- Contract testingChecking that two services keep to their agreed API contract: fields, types and status codes.
- Semantic versioningA MAJOR.MINOR.PATCH version format where each number signals how big a change is.
- Forced updateA blocking 'Update required' screen shown when the installed version is older than a minimum set on the server.