APIs, Networking & Integration Topics
API design, management, and integration patterns including REST, GraphQL, and other protocols. Covers API contract design, versioning strategies, error handling, idempotency, deprecation planning, and SDK/integration frameworks. Includes system-to-system integration, webhook patterns, and integration platform considerations. Excludes network infrastructure and network-layer protocols (see Network Architecture under Cloud & Infrastructure or a dedicated networking category if needed).
Enterprise Application Integration
Connecting large, heterogeneous enterprise systems into a coherent whole: interoperability across legacy and modern platforms, integration architecture for digital transformation, standards-based interfaces, and system-of-record coordination. Covers integration platforms/middleware, canonical data models, and the interoperability and governance concerns of complex multi-system landscapes.
SDK and Client Library Design
Packaging an API for developer consumption via SDKs and client libraries: ergonomic method surfaces, auth handling, pagination helpers, retry/backoff built in, error mapping, and versioning of generated or hand-written clients. Covers cloud/mobile SDK design, code generation from contracts, and keeping SDKs consistent across languages.
HTTP Protocol and Web Fundamentals
Application-layer HTTP semantics that underpin API behavior: methods, status codes, request/response headers, content negotiation, caching (ETags, Cache-Control), cookies, connection reuse, and HTTP/1.1 vs. HTTP/2 vs. HTTP/3 differences. Includes TLS/HTTPS at the request level and how proxies and load balancers affect requests. Foundational knowledge assumed before deeper API topics.
API Gateways and API Management
The management layer in front of APIs: gateways for routing, authentication, rate limiting, request/response transformation, and observability. Covers API management concerns such as developer portals, key provisioning, plan/tier enforcement, analytics, and centralized policy. The operational and productization surface of an API program.
Rate Limiting, Throttling and Quota Management
Protecting API capacity and enforcing fair use: rate-limiting algorithms (token bucket, leaky bucket, fixed/sliding window), per-client quotas, throttling responses (429 semantics, Retry-After), and tiered plan enforcement. Covers where to enforce limits (gateway vs. service), distributed counters, and graceful degradation under load.
Third-Party and SaaS Integration
Integrating with external providers and SaaS platforms (CRM, marketing, payments, HR, and similar): consuming partner APIs, handling auth and rate limits you do not control, mapping external data models to internal ones, and resilience when a dependency is down. Covers connector/adapter design, sandbox testing, and managing vendor-specific quirks across many integrations.
API Security, Authentication and Authorization
Controlling who can call an API, what they may do, and defending it against abuse. Covers the access-control mechanics: API keys, OAuth 2.0 flows, OpenID Connect, JWT issuance/validation, session vs. token auth, scopes/roles for fine-grained authorization, token lifetime and refresh, mutual TLS, and machine-to-machine vs. user-delegated access. Also covers the adversarial hardening view: input validation, injection and deserialization risks, broken object-level authorization (BOLA), mass assignment, secrets handling, and the OWASP API Security Top 10, plus securing data in transit, preventing enumeration/scraping, and testing APIs for vulnerabilities.
Webhooks and Event-Driven Integration
Push-based integration where a provider notifies consumers of events: webhook delivery, signing/verification, retry and dead-letter handling, ordering and deduplication, and idempotent receivers. Covers designing outbound webhook systems, replay/backfill, and comparing webhooks to polling for third-party integration.