Part 6
3 chapters
Evolution & lifecycle
Evolve an API without breaking clients and delete under compliance rules: HATEOAS, soft deletion/GDPR purge, and versioning.
Chapter 12
HATEOAS
Let the response carry the links: expose exactly the state transitions valid from a resource's current state, so a client drives the booking lifecycle by following links instead of hard-coding URLs and rules.
Chapter 13
Soft deletion & GDPR purge
Delete without losing the audit trail, then erase for good under compliance: soft-delete hides a booking from normal reads while keeping it addressable for audit, and a purge honours the GDPR right to erasure.
Chapter 14
Versioning
Evolve the API without breaking clients: compare URI, query, header, and media-type versioning, serve an old and a new representation of the same resource, and reason about what each choice does to caching.