Thunder Client: An open-source Postman alternative built in to Visual Studio Code

Thunder Client: An open-source Postman alternative built in to Visual Studio Code

This is not a sponsored post - I just find this tool useful and am sure you will too!

While developing, I often find myself in need of working with APIs, whether it be building them, consuming them, or both. In order to test and debug APIs, a tool to allows me to send HTTP requests and analyze responses is indispensable. Until recently I had been exclusively using Postman, one of the most popular API testing tools. However, I recently came across a lighter alternative that still does everything I need, and it's free and open-source: Thunder Client.

What is Thunder Client?

Thunder Client is an extension for VS Code. It allows you to send HTTP requests, visualize responses, and manage API testing directly from your editor. It provides a simple user-friendly interface that's designed to make your API testing experience smooth and efficient.

Why choose Thunder Client over Postman?

  • Seamless integration with VS Code
  • Lightweight and fast
  • Free and open-source
  • Simple and intuitive UI

Key Features of Thunder Client

  • HTTP request builder including GET, POST, PUT, DELETE, custom headers, query parameters, and request bodies
  • Response visualization including JSON, XML and HTML responses with syntax highlighting and collapsible sections making it easy to navigate complex data structures
  • Environment variables allowing you to store and reuse values across different requests (particularly useful when dealing with authentication)
  • Request history keeps track of all your past requests
  • Collections and folders allow you to organize your requests and share your API tests

How to get started with Thunder Client

  1. Install the extension: Open Visual Studio Code, go to the Extensions marketplace, search for "Thunder Client," and click on Install - or download directly from
  2. Launch Thunder Client: After installation, open the Thunder Client panel by clicking on the Thunder icon in the left sidebar, or by pressing the keyboard shortcut Ctrl+Alt+T (Cmd+Alt+T on macOS).
  3. Create a new request: Click on the "New Request" button to start building your HTTP request. Fill in the required information, such as the request method, URL, headers, and body.
  4. Send the request: Once your request is ready, click on the "Send" button to execute it. The response will be displayed in the lower section of the Thunder Client panel.
  5. Organize your requests: Create collections and folders to manage your API tests efficiently. You can also use environment variables to store and reuse values across different requests.

If you're a developer who relies on Visual Studio Code and frequently works with APIs, Thunder Client is a must-try extension. Its powerful features, intuitive interface, and tight integration with VSCode make it an excellent choice for anyone seeking a Postman alternative. Give Thunder Client a spin and see how it can improve your API development and testing workflow.


VS Code extension: