REST API
An architectural style for building APIs using standard HTTP methods (GET, POST, PUT, DELETE). Resources are identified by URLs.
What is REST API?
An architectural style for building APIs using standard HTTP methods (GET, POST, PUT, DELETE). Resources are identified by URLs.
REST API is a foundational concept that sits in the Core Fundamentals area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "REST API" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn REST API in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the REST API lessonSee also
Related glossary terms you might want to look up next.
HTTP
The protocol powering the web. A request-response model where clients ask for resources and servers respond. Stateless by design.
GraphQL
A query language for APIs where the client specifies exactly what data it needs. No over-fetching, no under-fetching. One endpoint to rule them all.
gRPC
A high-performance RPC framework by Google using Protocol Buffers and HTTP/2. Much faster than REST for service-to-service communication.
API Gateway
A single entry point for all client requests that routes them to the appropriate microservice. Handles auth, rate limiting, and request transformation.