Backward-compatible API versioning

TL;DR

• The API needed to evolve without breaking older integrations immediately.
• I needed clients to pin behaviour while newer consumers used the current contract.
• I used date-based version context to transform requests and responses across boundaries.
• The result was a clearer upgrade path for consumers and safer room for platform changes.

APIs need to change without breaking every existing integration at the same time. Versioning gives change a place to stand.

Where it started

Changing an API contract can improve the platform while still breaking consumers who rely on older shapes.

What needed to change

Date-based versions let clients pin behaviour. Older tokens can keep receiving transformed payloads while newer clients use the current contract.

What I built

Requests carry version context through headers or token metadata. The API can transform incoming requests or outgoing responses when a version boundary requires it.

What changed

Breaking changes become explicit. Teams can improve the platform while giving external consumers a clearer upgrade path.

What I would watch

Compatibility code has a cost. Each version boundary needs an owner and a plan for when it can be retired.