1. Integration with other tools: Postman offers extensive integration capabilities with various tools and platforms. It allows seamless integration with popular tools like Jenkins, Git, and Newman, which helps in automating the API testing process. On the other hand, Rest.li emphasizes integration with LinkedIn's ecosystem and is tightly integrated with other LinkedIn tools, making it the preferred choice for developers working with LinkedIn services.

2. Language Support: Postman supports multiple programming languages, including JavaScript, Python, Ruby, and more. This allows developers to write test scripts in their preferred programming language, enhancing flexibility and ease of use. In contrast, Rest.li is more focused on Java as its primary language. It provides a Java client library and encourages the use of Java for building APIs, limiting the language options available for developers.

3. Data Modeling: Rest.li has a strong emphasis on data modeling as it provides a robust schema-based approach. It utilizes the Avro schema for defining data models, enabling automatic data validation and enforcing data consistency across APIs. Postman, on the other hand, does not have built-in support for data modeling and validation. Developers need to handle data validation manually, which can be a time-consuming and error-prone process.

4. API Documentation: Postman includes a feature-rich documentation editor that allows developers to create detailed API documentation effortlessly. It offers customization options, such as adding code snippets, images, and examples, which enhances the readability and understanding of APIs. Rest.li provides its own built-in documentation generator, which automatically generates API documentation based on the defined resources. While it covers the essentials, Rest.li's documentation may not offer the same level of customization and flexibility as Postman.

5. Development Environment: Postman provides a full-fledged development environment where developers can write, test, and debug APIs. It includes features like code autocompletion, syntax highlighting, and environment variables, making it an ideal choice for developers who prefer an integrated development experience. Rest.li, on the other hand, focuses more on being a lightweight framework for building scalable and high-performance APIs. It does not offer the same level of development environment features as Postman.

6. Community Support: Postman has a large and active user community. It offers extensive resources, including forums, blogs, and tutorials, where developers can seek help, share knowledge, and learn from others. The community-driven support helps in quickly resolving issues and staying up-to-date with the latest trends in API testing. Rest.li, being a tool developed by LinkedIn, may not have the same level of community support as Postman. However, it benefits from LinkedIn's backing and is backed by a strong engineering team.

In summary, Postman excels in integration capabilities, multi-language support, and a comprehensive development environment. Rest.li, on the other hand, stands out with its focus on LinkedIn ecosystem integration, strong data modeling capabilities, and automatic documentation generation. The choice between the two tools depends on the specific requirements and preferences of the development team.