OpenAPI vs Rest.li: What are the differences?

Introduction

In the world of web development, understanding the key differences between OpenAPI and Rest.li is crucial for choosing the right tool for building and consuming APIs. Here are the specific differences that set them apart from each other.

1. Data Modeling: OpenAPI focuses on defining data models using JSON schema, which allows for detailed description of data formats. On the other hand, Rest.li utilizes a more structured data model with concepts like PDL (Pegasus Data Language) for defining data schemas and generating type-safe accessors.

2. Request and Response Structure: OpenAPI follows a standard format for defining request and response structures in YAML or JSON format. Rest.li, on the other hand, defines request and response data structures using PDL (Pegasus Data Language), providing a more formalized and structured approach.

3. Client and Server Libraries: OpenAPI has a wide range of client and server libraries available in different programming languages, making it easier for developers to work with APIs. Rest.li, on the other hand, focuses more on providing client libraries for specific languages like Java and supporting server-side generation.

4. Protocol Support: OpenAPI supports HTTP, REST, and GraphQL as communication protocols for APIs. Rest.li, on the other hand, primarily focuses on REST and doesn't provide native support for GraphQL.

5. API Documentation: OpenAPI has robust tools for generating API documentation using the Swagger UI, making it easier for developers to understand and test APIs. Rest.li provides basic tools for generating API documentation but lacks the same level of sophistication as OpenAPI.

6. Community and Adoption: OpenAPI has a larger community and wider adoption in the industry, making it a more popular choice for building and consuming APIs. Rest.li, while being backed by LinkedIn, has a smaller community and is less widely adopted compared to OpenAPI.

In Summary, understanding the key differences between OpenAPI and Rest.li in terms of data modeling, request and response structure, client and server libraries, protocol support, API documentation, and community adoption is crucial for making informed decisions in API development.