Undertow
Application server software
- Features
- Ease of use
- Ease of management
- Quality of support
- Affordability
- Market presence
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What is Undertow
Undertow is a lightweight Java web server and servlet container used to run HTTP applications and APIs. It is commonly embedded inside Java applications or used as the web layer within Java application server distributions. Undertow supports both blocking and non-blocking I/O and provides HTTP/1.1 and HTTP/2 capabilities, with a focus on low-level server building blocks and embeddability. Typical users include Java developers and platform teams building or operating Java-based services.
Embeddable Java server core
Undertow is designed to be embedded directly into Java applications, which can reduce the need for a separate external server process in some deployments. It provides programmatic configuration and a modular architecture suitable for custom runtimes. This fits teams building self-contained services or frameworks that package their own HTTP stack.
Supports modern HTTP features
Undertow includes support for HTTP/2 and WebSocket, enabling common real-time and multiplexed-connection use cases. It also supports the Java Servlet API, allowing many existing Java web applications to run with minimal changes. This makes it practical for both greenfield services and legacy servlet-based applications.
Flexible I/O and handlers
Undertow offers both blocking and non-blocking APIs and a handler-based architecture for composing request processing pipelines. This enables developers to choose simpler synchronous patterns or more event-driven approaches depending on workload needs. The design supports building custom middleware-like components without requiring a full Java EE/Jakarta EE stack.
Not a full platform runtime
Undertow is primarily a web server/servlet container rather than a complete enterprise application server platform. Capabilities such as full Jakarta EE profiles, integrated administration consoles, and broad built-in enterprise services typically come from higher-level distributions that may embed Undertow. Organizations needing a full application server feature set may need additional components.
Operational tooling is limited
As a core server component, Undertow does not emphasize turnkey operational features like GUI management, hosting control panels, or integrated edge delivery functions. Teams often rely on external tooling for configuration management, observability, TLS lifecycle, and traffic management. This can increase integration work compared with more operations-focused server products.
Smaller standalone ecosystem
Undertow is frequently consumed as a dependency within other Java platforms rather than as a standalone product with its own broad ecosystem of extensions and vendor support packages. Documentation and examples can be more developer-centric and lower-level than platform-oriented alternatives. Enterprises may need to validate support options through the distribution or vendor they adopt around it.
Plan & Pricing
| Plan | Price | Key features & notes |
|---|---|---|
| Open-source / Community | $0 (Apache License 2.0) | Fully open-source Undertow web server; available via Maven or as part of WildFly; embeddable Java web server; no paid plans or commercial tiers listed on the official site. |
Seller details
Red Hat, Inc. (IBM subsidiary) / Mandrel open source project
Raleigh, North Carolina, United States
1993
Subsidiary
https://github.com/graalvm/mandrel
https://www.linkedin.com/company/red-hat/
