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).
RESTful API Design
Focuses on designing resource oriented web APIs following Representational State Transfer principles and proper use of the Hypertext Transfer Protocol. Core skills include resource modeling and endpoint naming, use of correct Hypertext Transfer Protocol methods and semantics, status code selection and error response structure, idempotency and stateless design, request and response formats such as JavaScript Object Notation, pagination, filtering and sorting strategies, versioning and backward compatibility, authentication and authorization patterns, rate limiting and abuse prevention, caching and performance considerations, API contract testing and documentation, common anti patterns, and designing APIs that balance client usability with backend implementation concerns.
RESTful API Design and HTTP Fundamentals
Understanding REST architectural principles including resource-based URLs, proper HTTP methods (GET for safe retrieval, POST for creation, PUT for updates, DELETE for deletion), appropriate status codes (200 OK, 201 Created, 400 Bad Request, 404 Not Found, 500 Internal Server Error), and stateless communication patterns. Ability to design simple API endpoints following REST conventions.
Migrations, Versioning & Compatibility at Scale
Understand how to design systems that support long-term evolution while maintaining compatibility. Discuss strategies for API versioning, gradual deprecation of old versions, and migration paths for customers. Be able to discuss how to maintain backward compatibility while evolving a system, and trade-offs between maintaining multiple versions versus forcing migrations. For large platforms, discuss how to coordinate migrations across thousands of dependent systems.
Application Programming Interface Design and Rate Limiting
Focuses on designing scalable application programming interfaces that handle high request volumes while protecting infrastructure and preserving developer experience. Topics include API surface design and versioning, idempotency and retry semantics, authentication and authorization impacts, consistency and backward compatibility, and choosing protocols and payload formats. For scaling and protection discuss rate limiting and quota strategies such as token bucket, fixed window, sliding window, leaky bucket, per API key and per user limits, and hierarchical quotas. Cover backpressure, graceful degradation, circuit breakers, throttling responses and headers that communicate limits to clients, retry guidance, and strategies to avoid thundering herd effects. Also include operational concerns: monitoring and observability for request and error rates, metrics for usage and latency, metering and billing implications for usage based pricing, developer platform experience, documentation and developer tooling, testing at scale, and trade offs between strict protection and usability.
Service Communication and API Design
Design and specify APIs and interservice communication patterns for systems that must scale. Topics include REST design and best practices, API versioning and deprecation strategies, backward compatibility and API evolution, contract design between services, choosing protocols such as gRPC versus HTTP for internal or external communication, security and authentication patterns at the API level, performance and scalability considerations, observability and monitoring of service interactions, and strategies for evolving interfaces without breaking consumers.
Api Design and Versioning
Design and evolve application programming interfaces so they meet functional requirements while minimizing disruption to clients and services. Core skills include designing resource oriented endpoints, choosing and implementing versioning strategies, and preserving backward compatibility. Candidates should understand versioning approaches such as embedding a version in the endpoint path, using request headers to select versions, and designing non breaking changes so explicit version bumps are avoided. Important topics include idempotency, pagination, filtering, sorting, error response design, status semantics, rate limiting, authentication and authorization, and considerations for low bandwidth or mobile clients. At senior levels discuss operational and lifecycle concerns: deprecation policies and timelines, migration plans, compatibility testing, handling multiple client versions simultaneously in production, rolling deployments and coexistence strategies, contract testing, and alternatives such as remote procedure call frameworks. Expect trade off discussions around developer experience, client upgrade friction, monitoring and instrumentation for versioned traffic, and communication strategies with downstream consumers.
Building and Testing Restful Interfaces
Focuses on designing and testing robust representational state transfer style application programming interfaces. Topics include resource modeling and uniform resource locator design, versioning strategies, consistent status codes and structured error responses, pagination and filtering approaches, input validation and schema enforcement, authentication and authorization integration, idempotency for safe retries, and performance considerations such as caching. Testing topics include unit tests for handlers, integration tests with test doubles or isolated test databases, contract testing for client server agreements, end to end testing approaches, test data management, and continuous integration practices that maintain interface stability.
API Design and Implementation
Design and implement application programming interfaces and the server side request handling required for production services. Topics include resource modeling and endpoint design, representational state transfer versus remote procedure call systems and when to choose each, HTTP method semantics and status codes, pagination and cursor strategies, versioning and backward compatibility, rate limiting and throttling headers, idempotency and exactly once processing approaches, request validation and middleware patterns, error response design and retry semantics, serialization formats and schema evolution, streaming endpoints, contract definition and interface tooling, security at the API boundary, monitoring and observability for APIs, and trade offs between public internet facing APIs and high performance internal RPCs.
API Design and Integration
Design and evaluate application programming interfaces for external and internal consumption. Topics include resource and schema modeling for RESTful APIs, GraphQL schema and resolver design for diverse clients, and when to choose gRPC style remote procedure calls for high performance internal services. Candidates should address consistent error responses including problem details, pagination and filtering strategies, versioning and deprecation plans, idempotency keys and safe retry semantics, rate limiting headers and status codes, authentication and authorization patterns, contract testing, monitoring and observability, and how to balance backward compatibility with iteration velocity.