Rocket vs Vapor: What are the differences?

1. Execution Model: Rocket uses a synchronous blocking I/O model where each request is handled by a separate thread. In contrast, Vapor utilizes an asynchronous non-blocking I/O model based on Apple's SwiftNIO framework, which allows for more efficient handling of a large number of concurrent connections.

2. Templating: Rocket relies on external templating engines such as Askama or tera for creating dynamic HTML content, requiring additional setup and dependencies. On the other hand, Vapor has its own native templating language called Leaf, which simplifies the process of generating dynamic content within the framework itself.

3. ORM Support: Rocket offers built-in support for the Diesel ORM, providing a robust way to interact with databases through Rust code. Vapor, however, has a more modular approach to ORM support, allowing developers to choose from various libraries such as Fluent or Vapor's own Fluent ORM for database interactions.

4. Middleware: Rocket has a more limited selection of built-in middleware compared to Vapor, which provides a wide range of middleware options out of the box such as CORS, sessions, and authentication. This difference in middleware availability can impact the ease of implementing common web application features in the two frameworks.

5. Community and Ecosystem: Vapor has a larger and more active community compared to Rocket, resulting in more third-party packages, resources, and support available for developers using the framework. This broader ecosystem can be advantageous for developers looking to leverage existing tools and solutions in their projects.

6. Learning Curve: Rocket's API design tends to be more explicit and verbose, which can make it easier for beginners to understand and work with. In contrast, Vapor's more concise and expressive API might have a steeper learning curve for newcomers but can lead to more concise and elegant code once mastered.

In Summary, Rocket and Vapor differ in their execution models, templating support, ORM options, middleware availability, community involvement, and learning curve.