API quality

API quality interviews test durability: backward compatibility, rate limits, auth boundaries, documentation, contract tests, and operational signals that protect consumers.

Subtopics: rate limits and API auth, and documentation with contract testing.

On interviews: describe how you would ship a breaking change safely, throttle abusive clients, and catch schema drift before production.

Common pitfalls: docs that lag code, consumer tests only on mocks that lie, and global rate limits that punish bursty legitimate traffic.

The trade-off is balancing simplicity, performance, safety, and operability — name which axis you optimized and what cost you accepted.

Checklist:

• Version and deprecate with measurable consumer impact.
• Scope credentials, quotas, and Retry-After guidance.
• Keep examples, schemas, and CI contract checks aligned.
• Monitor per-consumer errors and latency budgets.