Newman vs OpenAPI: What are the differences?

Introduction

Newman and OpenAPI are two widely used tools in the field of API development and testing. While both serve important purposes, there are key differences between the two that make them suitable for specific use cases. This article aims to highlight these differences to help developers choose the right tool for their needs.

1. Execution Environment: Newman is a command-line tool that runs Postman collections, while OpenAPI is a specification that defines API endpoints, request/response formats, and other details. While Newman is used for running and testing APIs, OpenAPI is more focused on defining and documenting APIs.

2. Granularity of Testing: Newman is primarily used for functional testing where it can test individual API endpoints, execute scripts, and validate responses. On the other hand, OpenAPI is used for more high-level validation and documentation of APIs, focusing on the bigger picture rather than individual endpoint testing.

3. API Documentation: While Newman does not provide built-in functionality for documenting APIs, OpenAPI is designed specifically for API documentation. With OpenAPI, developers can generate interactive documentation, such as Swagger UI, that helps users understand how to utilize and interact with the API.

4. Code Generation: OpenAPI allows for code generation by providing client libraries and server stubs based on the API specification. Newman, however, does not have this feature. OpenAPI's code generation helps streamline the development process by providing pre-built code that can be easily integrated into client applications or used as a starting point for server implementation.

5. Collaboration and Standardization: OpenAPI provides a standardized way of documenting and defining APIs. This allows teams of developers to collaborate more effectively, as everyone can work with a shared understanding of the API structure and functionality. Newman, being primarily focused on running Postman collections, does not offer the same level of collaboration or standardization.

6. Integration with CI/CD: Newman can easily be integrated into Continuous Integration/Continuous Deployment (CI/CD) pipelines for automated testing. OpenAPI, on the other hand, is not directly integrated into CI/CD pipelines but can be used in conjunction with testing tools like Newman or other API testing frameworks.

In summary, Newman is a command-line tool used for functional testing of APIs, while OpenAPI is a specification used for documentation, validation, and code generation. Newman focuses on individual endpoint testing and automation, while OpenAPI provides a higher-level view of the API structure and allows for collaboration and code generation.