API regression testing

Check if your API continues to work as expected after introducing changes or updates.

Overview

Any time you make changes to an API—fixing bugs, refactoring code, or adding features—you risk breaking something that used to work. This regression testing template helps you catch those breakages early by running automated checks against your existing endpoints.

Use it to verify core behaviors, data structures, and performance after each change. It’s a simple way to ensure stability across releases, especially when working on internal APIs, shared services, or APIs used by multiple teams.

What is regression testing?

Regression testing ensures that new changes don’t unintentionally break existing functionality. In API development, that means verifying that all the core endpoints still return the expected status codes, headers, data formats, and response times—even after something changes behind the scenes.

It’s especially important when multiple services depend on your API, or when you’re working in microservices or CI/CD environments where things ship frequently.

What is the regression testing template?

This template is a ready-to-use collection designed for automated API regression testing. It gives you a set of reusable test cases to validate core functionality after changes—so you don’t have to rebuild your checks every time.

It’s built for quality engineers, backend devs, and platform teams who want a fast, repeatable way to run validation across endpoints as part of their dev or release workflows.

What does the template contain?

Status code checks — ensure endpoints return the right HTTP codes
JSON schema validation — confirm responses match expected structures
Custom data checks — verify that business logic or specific values are still correct
Header validation — confirm required headers and values are returned
Response time checks — track performance and identify slowdowns

You can extend or modify any of these to reflect your own API's requirements.

How to perform regression testing with this template

Review the template: Read the included tests and documentation to understand what’s being checked.
Set up your environment: Configure base URLs, authentication, and any required variables.
Customize the test cases: Update request URLs, bodies, and validations to match your own API.
Add test data or scenarios: Incorporate edge cases or data variations to increase coverage.
Run the test suite: Manually or via CI to validate behavior after every release.
Investigate failures: Any failed check could point to a regression or breaking change—review and resolve.
Schedule automated runs (optional): Use Newman or Postman monitors to run these tests regularly or post-deploy.