Undertow is a Java web server built on non-blocking IO that delivers high performance for web applications.
The project addresses the need for efficient server-side request handling by implementing a core HTTP server architecture based on non-blocking input and output operations. This approach allows the server to handle many concurrent connections without dedicating a thread to each one, reducing resource consumption and improving throughput. Undertow provides both blocking and non-blocking IO modes, giving developers flexibility in how they structure their applications.
Undertow suits teams building Java web applications that require strong performance characteristics and standards compliance. The project implements Servlet specifications up to version 6.0 and provides a Jakarta-compliant WebSocket implementation, making it appropriate for applications that need to follow enterprise Java standards. It integrates with the WildFly application server ecosystem, so adoption makes particular sense for organizations already invested in that platform or considering it. The tool is suitable for projects where connection concurrency and resource efficiency matter, such as APIs handling many simultaneous clients or services deployed in resource-constrained environments.
The project maintains active communication channels including a dedicated development group and Zulip chat integration with the WildFly community, indicating ongoing engagement with users and contributors. Security issues are handled through a formal disclosure process with Red Hat's security team, reflecting mature practices around vulnerability management. The project tracks issues through a dedicated system and maintains documentation on its website, suggesting sustained attention to both bug resolution and user guidance.
