What are service versioning strategies in microservices?

As services evolve, their APIs must be versioned to allow consumers to upgrade at their own pace without breaking changes. Common strategies include: URI versioning — embed the version in the URL path (/api/v1/orders, /api/v2/orders), which is simple and explicit; Header versioning — pass the version in a request header (Accept: application/vnd.myapp.v2+json), keeping URLs clean; Consumer-driven contract testing (Pact) — automatically verify that new service versions are still compatible with all known consumers; and additive changes only — follow backward-compatible rules: add new fields (never remove or rename), add new endpoints, and make new fields optional. Semantic versioning (MAJOR.MINOR.PATCH) helps communicate the impact of changes to consuming teams.