API Design A Visual Guide

Learn to design APIs as clear, dependable contracts.

This illustrated guide introduces API design for beginners and new systems engineers. Explanations, diagrams, and examples connect the decisions a provider makes with the behavior a consumer can safely expect.

Build a foundation in HTTP, resource and operation design, request and response schemas, validation, error handling, and collection pagination. Explore how idempotency, retries, and concurrency affect real interactions between systems.

Continue into security and privacy, compatibility and versioning, documentation and testing, production operation, asynchronous communication, and choosing an interaction style. The emphasis is on understanding the purpose and trade-offs behind each design choice.

Read the chapters in order to develop your contract mindset, then use the relevant topics when discussing or reviewing an API with your team.