Undertow
Undertow is a lightweight, high-performance web server written in Java, developed by Red Hat as part of the JBoss/WildFly application server. It provides a flexible, non-blocking I/O architecture for handling HTTP, WebSocket, and Servlet requests efficiently. It is designed to be embeddable, allowing developers to integrate it directly into applications without requiring a full application server.
Developers should use Undertow when building high-throughput, low-latency web applications in Java, especially for microservices or embedded scenarios where minimal resource usage is critical. It is ideal for real-time applications using WebSockets or for serving static content quickly, as its event-driven model outperforms traditional blocking servers like Tomcat in concurrent request handling.