Falcon

Uses lightweight fibers to handle blocking operations without stalling the server, enabling efficient high-concurrency request handling as described in its multi-process, multi-fiber architecture.

Built-in support for HTTP/1, HTTP/2, and TLS eliminates the need for external proxies like Nginx, simplifying deployments and improving performance.

Replaces complex stacks such as Nginx+Passenger with a single server, reducing environment-specific bugs and setup overhead, as highlighted in the motivation section.

Seamlessly integrates with any Rack-based Ruby application, including Rails, via dedicated integration guides, ensuring broad applicability.

Supports WebSockets and interim responses for real-time communication and early hints, enhancing performance for modern web apps.