JSON-RPC Rewriter

Intercept and mock JSON-RPC responses for frontend development and QA testing.

JSON-RPC Rewriter — Testing Tool for Frontend Developers and QA. An essential extension for manual testing and frontend development. JSON-RPC Rewriter lets you intercept JSON-RPC requests directly in the browser and substitute the response body and headers — without touching the backend. Working on an app that communicates via JSON-RPC? Need to check how the frontend handles a specific server response — an error, an edge case, or particular data? Just define the desired response in the extension and the browser will receive exactly that. Features: - Substitute the response body of any JSON-RPC request by URL endpoint and method name - Override or add custom response headers - Enable and disable extension instantly without reloading the page Perfect for QA engineers and frontend developers who need to reproduce edge cases, test UI behavior across different server responses, or debug error handling — no backend changes or mock servers required. --- How to use: 1. Enter the JSON-RPC URL endpoint you want to intercept 2. Enter the JSON-RPC method name 3. Specify the response body you want to substitute 4. Add custom headers if needed 5. Save the rule and toggle the switch to On The responses of the specified request will be substituted automatically.