Our journey to finding Product-Market Fit

Requestly helps over 200,000 developers around the globe to build, test and mock APIs faster. What started as a simple tool to redirect JavaScript files has grown into an open-source platform that helps teams work with APIs and HTTP requests. Modern Requestly lets developers to:

• Intercept and modify any HTTP request
• Mock REST and GraphQL APIs
• Manage API collections with environments
• Test APIs with our powerful interface

Stage 1 (First Launch): Redirect JavaScript Files

The story begins with a common frustration developers face: Testing JavaScript changes on live websites. Every small change needed a deployment to test the local changes. We built a simple solution – a tool that could redirect production JavaScript to local bundles using Redirect Rule feature. Developers could now swap their production Javascript files with local JavaScript files and test changes instantly.

Stage 2 (Redirects + Modify Headers): Working Around Content Security Policy

Success of JS Redirects brought new challenges. Some websites had security-controls and had implemented Content Security Policy (CSP) headers that blocked the redirects to localhost or staging/dev domains. Instead of giving up, we adapted by adding HTTP header modifications, helping developers work around these security restrictions while keeping their sites secure.

Stage 3: Intercept & Modify all HTTP Requests

Our users started asking an interesting question: “If we can modify JavaScript files, why not APIs and other resources?” We expanded Requestly to handle every type of HTTP request:

• Complete HTTP traffic interception & modification capabilities
• API response mocking
• Request blocking capabilities
• Request Delay Simulation
• Injecting Scripts