API Versioning Strategies: URL, Header, and Query Parameter Approaches Compared

API versioning is one of those decisions that looks simple on day one and becomes a major headache on day 1000. The goal of versioning is to let you evolve your API over time without breaking existing clients — but the wrong strategy creates confusing URLs, complex infrastructure, and frustrated consumers who never know which version to use. This guide compares the four main API versioning strategies, covers when you actually need versioning (and when you don't), and shows how to implement each approach cleanly in Node.js with Express. When Do You Actually Need Versioning? Not every API change requires a version bump. Distinguish between breaking changes (require a new version) and non-breaking changes (safe to deploy without a version bump): Breaking changes — require new version: Removing a field from a response Renaming a field (e.g., user_name → username ) Changing a field's type (e.g., string → number) Changing HTTP method (e.g., PUT → PATCH) Removing an endpoint Changing authenti