What is goproxy?

Goproxy is a library for the Go programming language that lets you build a custom HTTP proxy. A proxy sits between a user's browser and the websites they visit, intercepting and potentially modifying web traffic. Instead of using a pre-built proxy tool with fixed features, this library lets a developer write code to control exactly what the proxy does with each request or response. At a high level, the developer creates a proxy server, then attaches small pieces of code called "handlers" to it. These handlers run every time a request passes through. For example, a handler could add a custom label to every outgoing request, or block access to specific websites during business hours. The README shows how you could reject connections to reddit between 8am and 5pm, returning a message like "Don't waste your time!" instead of the actual webpage. The proxy can also intercept secure HTTPS traffic using a technique the README calls "Man in the Middle," which lets it inspect and modify even encrypted connections. Someone would use this when they need more control than a tool like Fiddler offers. Fiddler is a desktop application meant for inspecting traffic on one machine, while goproxy is designed to run as a server handling traffic from multiple users at once. A practical use case the README mentions: gathering statistics on page load times for a website over a week. You could point all your users' browsers to a central machine running your custom proxy, and it would quietly collect data as they browse. The project considers itself beta-quality but reports positive feedback from people running it in production. It supports transparent proxying and can automatically generate the certificates needed to inspect HTTPS traffic. The author chose a Go-compatible BSD license but notes a willingness to change it if that license blocks someone from using the software.