Windows Copilot API is an unofficial Python library and OpenAI-compatible HTTP server that bridges the consumer Microsoft Copilot chat service. It uses a pure-HTTP driver with curl_cffi to impersonate Chrome and speak Copilot's WebSocket protocol, handling authentication, proof-of-work challenges, and Cloudflare Turnstile clearance in-process. A Playwright-based browser module enables interactive sign-in and scheduled clearance refresh. The server wraps the library behind FastAPI endpoints exposing /v1/chat/completions and /v1/models with full streaming support, rate limiting, and concurrency serialization to cope with Copilot's single-account constraints. Notable features include transparent token refresh, conversation persistence, and a diagnostic tool for session debugging. The codebase is well-structured, with clear separation of concerns across protocol constants, challenge solvers, models, and drivers. It demonstrates advanced reverse-engineering and browser-emulation skills.