Rapidoid vs Undertow: What are the differences?

Introduction

In this article, we will discuss the key differences between Rapidoid and Undertow, two popular Java web frameworks. Both Rapidoid and Undertow are known for their high performance and scalability, but they have some distinct characteristics that set them apart. Let's dive into the details.

1. Embedded Server Architecture: Rapidoid is designed as an embedded server with minimal dependencies, providing a lightweight and easy-to-use solution for building web applications. On the other hand, Undertow is primarily a web server that can be embedded in Java applications, providing a more modular approach with additional features such as servlet support, load balancing, and reverse proxy capabilities.

2. Configuration Options: Rapidoid follows a convention-over-configuration approach, aiming for simplicity and fast development. It offers a minimalistic configuration where most defaults work out of the box, reducing the need for explicit configuration. In contrast, Undertow provides a highly configurable environment, allowing developers to fine-tune various aspects of the web server and customize it according to specific requirements.

3. Concurrency Model: Rapidoid follows a single-threaded, event-driven architecture, which allows it to achieve exceptional throughput and low latency. It leverages non-blocking I/O and async processing to handle a significant number of requests concurrently without the need for traditional thread-based concurrency. On the other hand, Undertow uses a thread-based concurrency model, where each incoming request is assigned to a separate thread. This approach provides familiar programming paradigms but may suffer from scalability issues under high loads.

4. Developer Productivity: Rapidoid aims to streamline development by providing a simplified API and a set of productivity-enhancing features. It focuses on developer convenience with features like automatic request/response serialization, easy dependency injection, and a simple routing mechanism. Undertow, while being more feature-rich, requires developers to write more explicit code for handling requests, managing dependencies, and configuring various aspects of the web server.

5. Community and Ecosystem: Rapidoid has a smaller but passionate community, with a focus on rapid development and simplicity. It provides a limited set of modules and plugins, but they are designed with ease of use in mind. On the other hand, Undertow benefits from the wider Java ecosystem and its integration with other popular frameworks like JBoss/Wildfly. It offers a rich set of extensions and libraries, covering various use cases and providing a more extensive ecosystem.

6. Maturity and Adoption: Rapidoid is a relatively new framework in comparison to Undertow, which has a longer history and wider adoption. Undertow is backed by Red Hat and has been extensively used in production environments with proven performance and stability. Rapidoid, while gaining popularity for its performance and simplicity, may be perceived as less mature or less battle-tested by some organizations.

In summary, Rapidoid and Undertow have different design philosophies and target different use cases. Rapidoid focuses on simplicity, minimalism, and fast development, while Undertow offers a more feature-rich environment with extensive configurability. The choice between the two depends on the specific requirements of the project, the desired level of control, and the development team's preferences.