Application Programming Interface — a set of rules and endpoints that allow different software systems to communicate. Web APIs typically use HTTP methods (GET, POST, PUT, DELETE) to exchange data in JSON format.

JavaScript Object Notation — a lightweight text format for data exchange. JSON supports strings, numbers, booleans, null, objects, and arrays. It's the standard format for API responses and configuration files.

Standard request methods that indicate the desired action on a resource. GET retrieves data, POST creates, PUT/PATCH updates, DELETE removes. Each method has semantics about safety and idempotency.