How to version REST endpoints, evolve GraphQL schemas, and ship mobile updates — without leaving existing users behind.
Why It Matters
Every deployed API is a contract. Every mobile binary installed on a user's phone is a snapshot of that contract. The moment you change a response shape, rename a field, or remove an endpoint, you risk breaking clients you cannot force-update.
Backward compatibility is not about avoiding change. It is about managing change so that existing consumers continue to work while the system evolves underneath them.
This article covers three layers: REST API versioning, GraphQL schema evolution, and mobile app compatibility (React Native & Flutter). Each section delivers concrete patterns and production-ready code.
