urllib3 is a powerful, user-friendly HTTP client for Python. urllib3 brings many critical features that are missing from the Python standard libraries: Thread safety. Connection pooling. Client-side SSL/TLS verification. File uploads with multipart encoding. Helpers for retrying requests and dealing with HTTP redirects. Support for gzip, deflate, brotli, and zstd encoding. Proxy support for HTTP and SOCKS. 100% test coverage.