APIs evolve. Adding fields is safe — removing or changing fields breaks clients. Versioning gives you a path to evolve the API without breaking existing integrations. When You Need Versioning You need a new API version when: Removing a field from a response Changing a field’s type or semantics Changing URL structure significantly Breaking backward-incompatible business logic changes You don’t need a new version for: Adding new optional fields (non-breaking) Adding new endpoints Bug fixes that don’t change the contract Strategy 1: URL Path Versioning The most common and explicit approach: