Intercept, Modify & Mock

API Responses in Real-Time

4.8 ⭐ 1100+ Ratings, 200,000+ users

Trusted by 200k+ developers at →

Your Development Companion

Gain comprehensive control over API responses for testing edge cases and accelerating frontend development.

Supports APIs triggered as XHR or fetch

Gain control over API responses triggered by XHR/Fetch requests. Eliminate the need for hardcoding in the codebase, and streamline your development workflow.

Test for Edge/Corner Cases

Simulate diverse API edge cases (e.g., missing parameters, null values, incorrect data types) without modifying the backend. This ensures robust error handling in your code.

Simulate Errors

Intentionally trigger specific error conditions within your codebase by altering API responses — test error pathways thoroughly without backend changes e.g. Simulate 404 on an API

Build frontend when the backend isn’t ready
(Mock/Sub API Responses)

Use the Modify Response rule to create mock APIs with custom responses and status codes. Easily disable these mocks when actual APIs become available.

GraphQL Support

GraphQL’s single-endpoint design can hinder targeted API modification. Requestly solves this with operation name filters, enabling precise response manipulation in GraphQL environments – just as you’d expect with REST APIs.

Collaboration & 1-Click Sharing

Promote consistency and accelerate development by sharing Requestly rules within your team. Choose between shared workspaces for real-time collaboration or targeted sharing with individual members.

Dynamic Response Generation

Generate API responses to your exact needs. Use JavaScript code to modify responses based on request headers, request body, URL, or original response. Perfect for complex testing scenarios or adapting API behavior without backend changes.

More HTTP Request & Response Manipulation Rules

These HTTP Rules designed for all your local development and testing needs.

Replace String

Replace part of URL like hostname, query values.

Modify Headers

Modify HTTP request & response headers.

Query Params

Add or Remove Query Parameters

Insert Script

Inject Custom JS & CSS on any website(s).

Delay Network

Simulate delay in response of API calls.

Modify Request Body

Modify body of POST requests.

Requestly Highlights

A comprehensive debugging suite with thoughtfully designed features for front-end developers.

For the developers, by the developers ❤️

From Debug to Deploy: Developers Trust Requestly

This is by far the best tool for managing request headers! Plus the developers are very active meaning you’ll get help if you’re ever stuck or need help solving a problem. I use it daily and couldn’t be happier.

Jose Browne
Senior Engineer at Reddit

App works as expected! Ran into some small issues while creating the rules but the support team was able to help and overcome those.

José Miguel Dias Fernandes
Development Lead at Vodafone

Requestly is user-friendly, brilliant and easy-to-use. I use it on an daily basis and it makes my work easier. After using other tools like Charles – Requestly is a nice new breath of air that I highly vouch for. Apart from the tool being amazing – the support from the Requestly team is phenomenal with them always going above and beyond for their clients.

Marius Ludick
Solutions Architect II at Amazon

Requestly is an amazing tool to get your development work less hassle. The product itself has evolved so much since day-1 and the company is really serious on helping their customer solves their problems. We had this nice session where they shared Requestly features and we were very impressed on its potential. A truly 5-star worthy.

Natchapol Thongruang
Senior Software Engineer at Agoda

We are using this extension in my current company as frontend developers to modify API responses and it works very very well. Highly recommend it.

Facundo Gadda
Front-end Developer at QUUACK

Requestly’s browser extension is remarkably easy to use. As a full-stack developer, I often need to test data-intensive UI for edge cases and performance. Using Requestly I can do it very easily by mocking network requests, without needing code changes or database seeding.

Divyanshu Sharma
Full-stack Developer at ShortLoop

Great tool for frontend developers and QA tester for API response, redirects, mock data and much more. Requestly removes the dependency on waiting for backend API’s. Really useful to have in your frontend development environment.

Samroon Michael
Senior Frontend Developer at

Requestly is awesome. I used to use Charles proxy in my day-to-day work but it always messed with my wifi. I haven’t had any issues with Requestly. Requestly’s UI is an amazing tool and great to work in.

Carl Hand
Senior Software Engineer at Workday

Requestly not just made it easier for us to develop, test & debug our code on our customer sites but also helped us do engaging product demos to our prospective clients.

Michael Levinson
Co-Founder & CPO at Joyned

I’m a big fan of Requestly, and use it on a daily basis as a QA Engineer. It removes the need to use Charles Proxy often, which is always nice. I can just use Requestly directly in Chrome

Mike Mitchell
QA Engineer at URBN

Awesome tool. I use it almost daily for my projects to modify request body, headers, etc. Would recommend it to every frontend developer out there. Thank me later 🙂 (Case Study)

Harsh Vats
Frontend Engineer at PingSafe