Fastify is a popular Node.js web application server that provides the best developer experience with minimal overhead and a powerful plugin architecture. It's widely used by developers globally to build scalable HTTP applications, including server-side-rendered, JSON, or GraphQL APIs. The project's success can be attributed to its active community and focus on improving the overall developer experience, making it an attractive choice for Node.js developers. Fastify's features, such as its router based on a radix trie data structure, have also garnered interest among developers. The project's latest release has introduced new features like improved logging serialization, schema substitution, and better TypeScript support. With its strong community and growing ecosystem, Fastify is an ideal choice for developers looking to build scalable HTTP applications.