Developers read your 400s more carefully than your docs. Design them like it.
Offset pagination feels obvious and betrays you at scale. Here's the cursor pattern, minus the hand-waving.
Every versioning strategy is a way of choosing who you're going to disappoint. Choose deliberately.
Retries, ordering, idempotency, signatures. The word 'webhook' hides four hard problems.
Publishing a client library changes your relationship with breaking changes forever.