Production REST API FAQs

Over 85% of internal corporate microservices run on REST/HTTP/JSON. The reasons are operational: REST endpoints work out of the box with standard reverse proxies (NGINX, Envoy, Traefik), cloud load balancers (AWS ALB), and API gateways (Kong, Apigee) without custom protocol parsers. Engineers in polyglot teams can debug with curl and Postman in seconds without compiling Protocol Buffer schemas. Furthermore, HTTP caching (ETags, Cache-Control) reduces database load across internal services, and OpenAPI 3.1 provides automated SDK generation and contract testing without binary coupling.

No. Analyzing publicly documented API design patterns, headers, HTTP status codes, and architecture decisions of companies is standard industry practice protected under the doctrine of nominative fair use. Nominative fair use permits the factual use of a trademarked name to refer to the product or service itself for comparative analysis, commentary, and education. To maintain professional rigor, sites include a standard educational disclaimer stating that product names and trademarks belong to their respective owners.

Returning 200 OK for errors is one of the most destructive anti-patterns in backend engineering. It completely breaks HTTP infrastructure: Edge CDNs and proxies will cache your error payload and serve it to other users; API gateways fail to register error rate spikes; circuit breakers won't trip; and typed client SDKs are forced to parse every successful body manually to check for error flags rather than catching standardized HTTP exceptions.

PUT represents a full replacement of the target resource representation. If you send PUT /users/1 with only { 'email': 'new@mail.com' }, any omitted fields (like name, avatar, bio) should conceptually be cleared or reset to defaults. PATCH represents partial modification (RFC 5789). In production, most teams implement either JSON Merge Patch (RFC 7396) or standard partial object merging.

The cleanest production pattern is a dual-token architecture: Give access tokens short lifespans (5 to 15 minutes), and keep long-lived refresh tokens in a database or Redis. On logout, revoke the refresh token immediately. For emergency immediate revocation of active access tokens, store a user-level 'token_version' or 'password_changed_at' epoch in your cache, or maintain a fast Redis blacklist for the remaining TTL of the compromised JWT.

In relational databases, OFFSET 50000 requires the query engine to read 50,020 rows off disk, sort them, and throw away the first 50,000 before returning 20. As data grows, latency degrades linearly. Furthermore, offset pagination suffers from 'page drift': if a new item is inserted on page 1, a user browsing page 2 will see duplicate items. Cursor pagination uses a deterministic pointer (e.g. WHERE id > last_seen_id ORDER BY id ASC LIMIT 20), executing an instantaneous index seek in O(log N) time.

RFC 9457 defines a standardized media type (application/problem+json) with 5 standard fields: type (URI identifying problem type), title (short human-readable summary), status (HTTP status code), detail (specific occurrence explanation), and instance (URI of the request). Using RFC 9457 gives your API ecosystem consistent machine-readable error contracts across all microservices and third-party consumers.

LLM agents (OpenAI, Claude, Gemini) use function calling and tool use powered by OpenAPI 3.1 schemas. When an agent receives a prompt, it inspects your API's OpenAPI specification, extracts endpoint paths, parameters, and JSON schemas, and synthesizes structured JSON payloads to execute the HTTP requests. Designing for AI agents requires strict JSON schema typing, descriptive parameter summaries, and Idempotency-Key support on mutative requests to guard against agent retries.

URI path versioning (/v1/customers) is used by 90%+ of production APIs (Stripe, GitHub, Twilio, OpenAI, Google). While purists argue for header-based versioning via content negotiation, URI versioning is vastly superior in practice: it can be tested directly in browser address bars, routed easily in CDNs and load balancers, inspected clearly in access logs, and does not depend on custom client header logic.