api-and-interface-design

Design consumer-first API contracts by defining request/response shapes, errors, auth, and idempotency before code hardens them. This approach forces explicit specification of consumer-visible interfaces, reducing compatibility mistakes and unclear operational semantics across endpoints and SDKs.

Handle backward compatibility by classifying additive, deprecating, and breaking changes up front. Require versioning, migration, rollback, and consumer impact evidence when modifying event schemas or webhook payloads to ensure external modules maintain stable behavior.

Specify idempotency and retry semantics by documenting operational behaviors within the interface contract. Define exactly how endpoints handle duplicate requests, retry scenarios, and pagination or collection behavior to provide clear operational guarantees for consumers.

Yes, contract-first interface specification applies to CLI surfaces, plugin configurations, SDK boundaries, and GraphQL operations. It defines required versus optional fields, nullability, defaults, and unknown-field behavior from the consumer's perspective before implementation.

Verify API contracts by attaching concrete validation, diff, and test commands to the specification. Score and gate completion on confidence while ensuring evidence-backed decisions cover shape, errors, auth declarations, and operational semantics.

API implementations become confusing when consumer-visible interfaces are not specified as explicit contracts before code hardens them. Forcing contract-first design prevents breaking changes by requiring evidence-backed decisions for shape, errors, and compatibility.