Fastify Node.js Web Framework

Fastify is a highly performant web framework for Node.js inspired by Hapi and Express, focused on providing the best developer experience with the least overhead and a powerful plugin architecture. The framework achieves throughput up to twice that of Express by leveraging an efficient routing engine based on a radix tree data structure, schema-based serialization that compiles JSON serializers at startup using fast-json-stringify, and asynchronous logging through Pino that processes over 100,000 log lines per second. With over 10 million monthly npm downloads, it powers production applications at Mercedes-Benz Group, SerpApi, Handsontable, Elastic, and numerous other organizations. The plugin system encapsulates functionality in self-contained units that automatically manage dependency resolution, scope decoration, and lifecycle hooks including preHandler, preSerialization, onSend, and onError. Built-in features include input validation through JSON Schema with Ajv, output serialization for consistent response shapes, automatic TypeScript type generation from schemas, request lifecycle hooks for middleware-like behavior, and first-class async-await support. The framework provides intelligent request context management that avoids closure overhead through encapsulated request objects, supports hooks for authentication, rate limiting, CORS, helmet security headers, and multipart file uploads through official plugins. Notable technical advantages include hot module replacement during development, graceful shutdown handling, automatic content negotiation, support for HTTP/2, and the ability to run custom functions before or after route handlers. The project is part of the OpenJS Foundation and maintains an extensive ecosystem of over 300 community plugins.