jsproxy

jsproxy is an online proxy server built around a browser technology called Service Workers. A proxy is a middleman server: instead of your browser talking directly to a website, the request goes through the proxy first, which fetches the content and passes it back. Traditional proxies do most of this work on the server side, which is expensive in CPU and bandwidth. jsproxy shifts the heavy lifting into the browser itself by using a Service Worker, which is a script that can intercept and modify network requests before they leave the browser.

The README is written in Chinese. The core idea is that the server only needs to forward traffic and modify HTTP headers, rather than parsing and rewriting the full page content. Because nginx handles the forwarding and the browser handles the content rewriting, the server load stays very low. The proxy also injects a JavaScript snippet into pages it serves, which rewrites browser APIs related to URLs so that the proxied page behaves as if it is running on its original domain rather than the proxy's domain.

Installation requires a Linux server with root access. A shell script handles the setup automatically. You can also run the frontend portion on GitHub Pages (a free static hosting service) and point it at your own backend, which can reduce bandwidth costs and give you a custom domain. Optional configuration lets you restrict which sites the proxy is allowed to forward to, and a separate security script can block the proxy from accessing internal network addresses to reduce certain server-side risks.

The project description states its intended uses as technical research into website mirroring, sandboxing, phishing detection techniques, and accelerating access to frontend resources. The README explicitly cautions against using it for illegal purposes.

A serverless variant using Cloudflare Workers is also mentioned for users who want a long-running demo without managing their own server. The project is released under the MIT license.