Browser Extension

Learn how to use Browser Extention to intercept HTTP Request and Responses

Requestly’s browser extension is the simplest way to intercept and modify HTTP requests and responses directly within your browser. It’s lightweight, easy to install, and perfect for debugging frontend issues or simulating API responses—without needing to run a local proxy or configure complex setups.

Whether you’re a frontend developer testing new API integrations or a QA engineer simulating error scenarios, the browser extension gives you powerful tools right in your development environment.

Key benefits

• No proxy setup required – Works entirely within the browser.
• Quick debugging – Instantly view, rewrite, or mock API requests.
• Cross-browser support – Available for Chrome, Firefox, Edge, and more.
• Secure and isolated – Only affects traffic in the browser you install it on.

When to use the browser extension

Use the browser extension if:

• You only need to intercept traffic from websites or web apps.
• You’re testing frontend behavior and want a quick setup.
• You want to create rules to mock APIs, rewrite URLs, inject scripts, or modify headers.

How to intercept traffic using the extension

Once the browser extension is installed, you can start intercepting traffic with just a few clicks.

Follow the Browser Interception guide to get started →

This guide walks you through launching a connected browser, viewing traffic in the network table, and verifying the proxy setup.

Requestly’s Browser Extension is a lightweight interceptor that runs directly in your browser. It allows you to intercept, modify, and control both incoming responses and outgoing requests, making it a powerful tool for developers and testers.

Browser extension features

With the browser extension, you can:

• Modify requests – Change headers, query parameters, or request methods before they’re sent.
• Mock responses – Return custom JSON or status codes instead of hitting the real server.
• Redirect traffic – Route API calls to staging or mock URLs for flexible testing.
• Injectscripts/styles – Add custom JavaScript or CSS into pages on the fly.

Learn more about how to work with browser interceptor here.

Supported Browsers & Profiles

Requestly supports all modern browsers, and you can use it with many browsers like Google Chrome, Firefox, and Safari. Here’s a breakdown of the browser support:

• Chromium-Based Browsers

  Requestly is available on all Chrome-based browsers through the Chrome Web Store. This includes Google Chrome, Microsoft Edge, Brave, Opera, and others.

• Firefox

  We officially support Firefox and its variants, ensuring a seamless experience across different Firefox-based browsers.

• Safari (API Client Only)

  The Requestly extension is available for Safari, but currently, it only supports the API Client. Support for HTTP rules will be available soon.