API design standards and integration patterns

What You Can Do After This Chapter

Learning objective. Learner explains API versioning and lifecycle, pagination, rate limiting and quotas, and the error taxonomy that separates HTTP status from payment status. Learner designs idempotent payment creation, models payment resources in REST, and explains webhook signatures, retries, ordering and replay.

Practical assessment. Learner receives a case where a client retries a payment request after a network timeout, then explains the idempotency key handling, the conflict response, and the webhook that confirms settlement. Learner also designs the pagination for an account with 100,000 payments a year and the error taxonomy for the API.

Expected deliverables.

• Idempotency design note with retry cases
• Error taxonomy table
• REST resource model for payments
• Webhook specification: signature, retry, ordering, replay

Completion criterion. Learner explains the idempotency handling correctly, designs correct pagination, and separates HTTP status from payment status in the error taxonomy.