Postman Learning Center
Postman
Official documentation and guided tutorials from Postman covering how to send requests, write test scripts, chain calls into collections, mock servers and document APIs. Working through it makes you competent with the tool most teams use.
More resources on APIs
MDN Web Docs
MDN Web Docs is a comprehensive resource for learning and referencing web technologies, including HTML, CSS, JavaScript, and Web APIs. It offers tutorials, guides, code examples, and debugging tips to help you build, test, and troubleshoot web applications.
Public APIs
Community-maintained GitHub index of several hundred free public APIs, sorted by category with authentication, HTTPS and CORS support noted for each entry. Useful for picking a real data source when building practice projects.
REST API Tutorial
Reference site explaining REST as Roy Fielding defined it: the six architectural constraints, resource and URI design, HTTP methods, status codes, HATEOAS and idempotency. Reading it lets you judge whether an API is genuinely RESTful.
APIs for Beginners
Two-hour freeCodeCamp course by Craig Dennis explaining what APIs are, how HTTP requests, endpoints, headers and JSON work, then building small projects in Node.js and Flask against a real third-party API.
REST APIs with Flask and Python
Build REST APIs with Flask and Python! Learn to design, develop, and deploy robust APIs with expert Jose Salvatierra.
APIs and Microservices
Learn APIs & Microservices with this free course! Build robust backends and master API design with freeCodeCamp.