All 15 API Versioning questions
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.NET › API Versioning

How does semantic versioning (SemVer) inform decisions about when to bump an API's major, minor, or patch version?

Intermediate

Answer

Semantic versioning conventions (MAJOR.MINOR.PATCH) map naturally to API changes: a MAJOR bump signals breaking changes (removed fields, changed response shapes, incompatible behavior), a MINOR bump signals backward-compatible additions (new optional fields, new endpoints), and a PATCH bump signals backward-compatible bug fixes with no contract change. Most public API versioning schemes (like /api/v1, /api/v2) only expose the MAJOR component externally, treating MINOR/PATCH as internal implementation detail that doesn't require client action.
// Externally exposed: only major version
// /api/v1/products  /api/v2/products

// Internally tracked via SemVer in release notes:
// v1.3.2 -- patch fix, no client action needed
// v1.4.0 -- new optional field added, backward compatible
// v2.0.0 -- breaking change, new URL segment required
Real-world example An API's changelog documents every release using full SemVer internally (v1.4.2, v1.5.0) while only the major version (v1, v2) is ever reflected in the actual URL path clients call, keeping the versioning surface simple for consumers.

Common follow-ups: Should minor/patch versions ever be exposed in the URL?;How does this map to versioning conventions in package managers like NuGet?

RESTful Web APIs & Controllers;CI/CD Publishing & Deployment
All 15 API Versioning questions