I reverse engineered Windows Copilot into a free OpenAI compatible API (GPT-4, no API key, no billing)

So Microsoft gives you GPT-4 for free in Copilot. They just don't give you an API for it. So I made one.

It logs into your own Microsoft account once, saves the session, and exposes a local server at http://localhost:8000/v1 that speaks the OpenAI format. Point the official OpenAI SDK at localhost and it just works. Drop-in, zero code changes.

It's free because it uses your normal signed-in Copilot, no credits or paid plan(Which is free and unlimited). It's a drop-in OpenAI replacement that works with anything OpenAI compatible. It does streaming and multi-turn conversations.

It ends up being surprisingly useful as a smarter alternative to small local models for automation, side projects, and lightweight workloads where you don't want to burn real GPT-4 credits.

You can set it up on a spare Windows laptop or Windows server with a different Microsoft account (don't use original in case ban) and use it as a free AI endpoint for your own tools and agents.

Full disclaimer: it's an unofficial project, not affiliated with Microsoft, and it automates the consumer Copilot. It's intended for personal and educational use, so please don't abuse it.

It's my first time shipping something like this publicly, so I'm sure there are things I've missed or hidden bugs. Would genuinely love feedback on the approach, and whether the OpenAI compatibility layer holds up against your tools.

Roast it, I'll take notes. lol (If you need help to setup you can ask here or DM me)

Repo: https://github.com/sums001/Windows-Copilot-API