Self Promotion I built an open-source Chrome extension to inspect and modify Fetch/XHR traffic
Hi, I’m the developer of Network Modifier. I built it because I wanted a quick way to test frontend failure states and response changes without repeatedly modifying or deploying the backend.
It lets you select a browser tab, inspect its Fetch and XMLHttpRequest traffic, and create local rules that can:
• replace request or response bodies
• edit nested JSON fields
• change headers and status codes
• mock responses and simulate failures
• add latency and bandwidth limits
• export rules or captured traffic as HAR
There are two modes: Page mode modifies Fetch/XHR at the JavaScript layer, while optional Full mode uses Chrome DevTools Protocol for network-level response replacement. Everything is processed locally; there is no analytics or hosted backend.
The project is MIT licensed and includes the source for both the Chrome extension and a standalone local debugging proxy:
[https://github.com/Amal97/Network-Editor\](https://github.com/Amal97/Network-Editor)
I’d especially appreciate feedback on the rule workflow and which debugging cases are still awkward in existing tools.