RAML vs REST: What are the differences?

Introduction

RAML (RESTful API Modeling Language) and REST (Representational State Transfer) are both widely used in designing and documenting APIs. While REST is an architectural style for building networked applications, RAML is a specific language that can be used to describe and document RESTful APIs. Despite their similarities, there are several key differences between RAML and REST that developers should be aware of.

1. Design Approach: RAML is a language that provides a structured and standardized approach to design and document RESTful APIs. It allows developers to define the API's structure, data types, endpoints, and more in a machine-readable format. On the other hand, REST is an architectural style that focuses on simplicity, scalability, and modularity. It doesn't dictate any specific format or language for API design.

2. Documentation: One of the main advantages of RAML is its built-in documentation capabilities. With RAML, developers can generate interactive API documentation automatically from the API specification. This makes it easier for developers and consumers to understand how to interact with the API and explore its capabilities. REST, being an architectural style, doesn't provide any specific documentation features. Developers have to rely on external tools or manual processes to create API documentation.

3. Code Generation: RAML allows developers to generate code stubs automatically based on the API specification. These code stubs serve as a starting point for implementing the API logic in different programming languages. This can significantly speed up the development process and provide consistency across different implementations. REST, being an architectural style, doesn't provide any built-in code generation capabilities. Developers have to manually implement the API logic based on the design principles of REST.

4. Versioning: RAML provides built-in support for versioning APIs. Developers can define multiple versions of the API and specify the differences between them. This makes it easier to manage backward compatibility and introduce changes to the API without breaking existing client applications. REST, being an architectural style, doesn't provide any specific versioning mechanism. Developers have to handle API versioning manually, usually by including version numbers in the URLs or using custom headers.

5. Validation: RAML includes a validation mechanism that allows developers to define the expected structure and constraints of the API requests and responses. This enables automatic validation of the requests and responses against the specified rules, helping to ensure data integrity and consistency. REST, being an architectural style, doesn't provide any built-in validation mechanisms. Developers have to implement their own validation logic based on the requirements of the API.

6. Ecosystem and Tooling: RAML has a growing ecosystem of tools and libraries that support API development and management. This includes tools for generating documentation, code, and even testing API endpoints. REST, being an architectural style, doesn't have a specific ecosystem or tooling associated with it. Developers have to rely on general-purpose tools and libraries for implementing and managing RESTful APIs.

In summary, RAML is a language for designing and documenting RESTful APIs, providing features such as structured design, automatic documentation, code generation, versioning support, validation, and a dedicated ecosystem of tools. REST, on the other hand, is an architectural style that focuses on simplicity and scalability, without providing any specific language or tooling for API design and documentation.