Open Source
Intercept & Modify
Request Body in Real Time.
Change the way you test APIs. Check the API responses with different inputs, find edge cases, simulate API errors.
Override XHR/fetch Requests
Using Requestly Modify Request Body rule, you can override the API requests triggered by XHR/fetch. No need to hardcode APIs in frontend code anymore.
Test error paths in your code
Modify API request body to trigger different error paths in your codebase and test the flows without changing anything on backend. e.g. Simulate Payment Timeout Issue, Item out of stock Issue, etc.
1-Click Sharing
Use-Cases in teams are very similar so Requestly makes it easier to share the rules with each other and collaborate faster.
Trusted by developers at
Application and use cases
Here’s how you can use Requestly’s Modify Response feature in your daily workflow
Static Response
Allows you to intercept and replace the original server response with a predefined fixed JSON or string response
Dynamic response
Gives ability to modify the server response programmatically using JavaScript. Write custom JavaScript code that runs on the intercepted response and manipulate its content.
Fake status code
Enables you to change the HTTP status code of a server response. By modifying the status code, you can simulate different server responses without actually altering the content.
Intercept & Modify HTTP Requests
Boost Your Web Development: Advanced Tools for Seamless Debugging.
Redirect URL (Map Remote)
Redirect a request URL to another URL. e.g. Load local scripts in the production sites for faster debugging.
Override API Response
Test edge cases in your app by simulating API responses. Override XHR, fetch and AJAX responses.
Inject Custom Scripts
Add Custom JavaScript (JS) to Hide unwanted sections, add action buttons, inject your own libraries, etc.
Modify HTTP Headers
Add, Delete, Override Request & Response Headers. Can be used to remove X-Frame-Options, Content-Security-Policy, CORS Issues, etc.
Modify Query Params
Insert, Modify or Delete query parameters for URLs (or matching pattern). Burst cache for a request by assigning it a newer version.
Delay HTTP Requests
Simulate lag / delay to the response from specific URLs in a single click by using Requestly’s Delay Request Rule. No need to modify actual server.
More from Requestly
An open-source platform that speeds up your web development cycle 10X faster.
Session Recording
Data rich bug reporting with Network logs, Console logs, Session Video and environment details. Share it with your Engineering team for faster debugging.
Mock API Server
Generate custom API responses without actually having a pre-built API or a backend server. Edit Content-Type, Status Code, Headers, and Response body easily on the Mock Server.
Web-based API Client
A comprehensive and web-based tool for modifying and testing APIs. You can test the Mock APIs you’re creating here to fast track your development lifecycle.
For the developers, by the developers ❤️
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.
Just loved the way Requestly saved several person hours for our dev team by allowing us to redirect and intercept requests. The simple yet efficient rules allowed us to seamlessly redirect requests from a single staging front-end server to local backend servers. This meant that our devs didn’t need to build or run the front-end server locally when focusing on backend tasks.
Requestly is an incredibly useful tool for developers working on a large team with multiple staging envs, or numerous app endpoints for various APIs in a local environment. The Sessions feature is especially useful for documenting solutions or sharing with others since it captures the relevant network traffic, and screen recording enables others to easily reproduce. Requestly combines all the power of complicated tools like Charles Proxy and Postman in one app/chrome extension. I highly recommend giving it a try if you haven’t already–it will make your dev work so much easier. (Summarized)
Simple UI, Huge Impact Loved the intuitive UI for request body modification. Helped in confirming backend security with my senior engineer, even bested Postman Interceptor in some cases.
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)
Modifying requests and/or responses is the killer feature area for me. Redirect JS in prod, generate mocks, modify headers, map local, map remote, SessionReplay, Load a local JS bundle, override scripts, etc. etc. etc. – TOTALLY worth it and very useful.
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.
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.
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
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.
App works as expected! Ran into some small issues while creating the rules but the support team was able to help and overcome those.
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.