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.
express-slow-down is an Express.js middleware library that rate-limits clients by slowing down responses instead of blocking them outright. It wraps `express-rate-limit` internally, using a custom handler that computes a delay based on request count and configurable options like `delayAfter`, `delayMs`, and `maxDelayMs`. The middleware increments a per-client counter (via a store, defaulting to an in-memory store), and when the count exceeds a threshold, it delays subsequent responses. It supports custom stores, async functions for dynamic delays, and standard/legacy rate-limit headers. The codebase is well-structured TypeScript with comprehensive unit and integration tests, and follows modern ES module and TypeScript practices.