About This Book

This book teaches API testing with Postman from the ground up — no prior testing experience required, though readers who already test software will move faster. By the final page you will be able to design, build, run, and automate a professional API test suite, integrate it into a CI/CD pipeline, and use AI assistance productively and safely.

How the book is organised. Part I builds the conceptual foundation: what APIs are, how HTTP works, and why API testing matters. Part II covers the Postman essentials — workspaces, collections, requests, and responses. Part III is the heart of the book: writing tests, mastering variables and environments, advanced scripting, and designing a genuine test strategy. Part IV scales your work across a team with sharing, the Collection Runner, mock servers, and monitors. Part V moves everything to the command line and into CI/CD with the Postman CLI, Newman, Jenkins, and GitHub Actions. Part VI addresses the newest chapter in our profession: AI-assisted testing. Part VII is pure reference — an interview FAQ, an HTTP status code table, and a glossary.

Conventions. Numbered steps are actions for you to perform. Code blocks show JavaScript, terminal commands, or YAML exactly as you should type them. Values in {{doubleCurlyBraces}} are Postman variables. Callouts marked Best practice, Security note, or Pitfall flag the judgement calls that separate a working test suite from a professional one.

About the screenshots. Postman ships updates frequently. Some screenshots in this book show slightly earlier versions of the interface; where a menu or tab has been renamed, the text tells you the current name. The workflow and concepts are stable — a button may move, but the skill transfers.

Trademarks. Postman is a trademark of Postman, Inc. Jenkins, GitHub, Node.js, and all other product names mentioned are trademarks of their respective owners. This is an independent publication and is not affiliated with or endorsed by any of them.