SearXNG is a privacy-respecting metasearch engine that aggregates results from over 100 search engines (Google, Bing, DuckDuckGo, Wikipedia, academic sources, etc.) via HTTP requests. It runs as a Flask web application, supports multiple output formats (HTML, JSON, RSS), and includes a plugin system, bot detection, rate limiting, and user preferences stored in cookies. The architecture is a monolithic Python application with a separate TypeScript/Less frontend built with Vite. It uses Valkey/Redis for caching and rate limiting, and SQLite for persistent caches. The codebase is well-structured with a clear separation of concerns: engine modules implement a common request/response interface, result types are typed with msgspec, and plugins are registered via a simple hook system. It is actively maintained with CI/CD, Docker support, and comprehensive documentation.