undertow-io/undertow

Health v2 · maintenance only

Adoption not part of the score

3760 stars · 1054 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Undertow is a high-performance, non-blocking Java web server built on NIO, providing a core HTTP server, a Servlet 4.0/5.0/6.0 container, and WebSocket support. It is fully embeddable with a fluent builder API and a composition-based handler architecture, and serves as the default web server in WildFly.

Use cases

• embed a lightweight http server in a java application
• run a servlet container without a full application server
• serve websockets from a java backend
• build a custom non-blocking http server from composable handlers
• replace tomcat or jetty with a faster embedded server
• support http/2 in a java service

When to choose

• you need an embeddable, high-performance Java HTTP server with low overhead
• you want servlet support without a heavyweight application server
• you need WebSocket or HTTP/2 support on the JVM
• you want fine-grained control over server composition via handlers

When to avoid

• you need a non-JVM stack
• you want a batteries-included full application server rather than a library
• your team is unfamiliar with NIO and non-blocking programming models

Facets

library · maturity stable

http-server websocket middleware routing web-development backend developer-tools jvm cross-platform nio servlet-container http2 embeddable wildfly ajp

Member repositories

For agents

markdown · JSON · MCP: product_card(name="undertow-io/undertow")