What Scripting Language Does Postman Use?

Postman is a widely used API development and testing tool that simplifies the process of building, testing, and documenting APIs. It provides users with a user-friendly interface to send requests, receive responses, and analyze the data exchanged between clients and servers.

What is Postman?

If you are new to Postman, it is essential to understand that it is not a scripting language itself. Instead, Postman makes use of JavaScript as its scripting language for writing tests and automating API workflows.

Using JavaScript in Postman

JavaScript is a versatile scripting language widely used for web development. It allows developers to create interactive elements, handle events, manipulate data, and perform various other tasks on both the client-side and server-side. In Postman, JavaScript can be used to write scripts for performing tasks like assertions, setting up environment variables, handling response data, etc.

Writing Tests in Postman using JavaScript

In Postman, you can write tests using JavaScript to verify the expected behavior of your API endpoints. Tests are executed after sending a request and receiving a response. They help ensure that the API is functioning correctly by asserting conditions on the response data or headers.

To write tests in Postman using JavaScript, you need to navigate to the “Tests” tab in the request builder. Here is an example of how a test script looks like:

// Example test script
pm.test("Response time is less than 200ms", function () {
    pm.expect(pm.response.responseTime).to.be.below(200);
});

pm.test("Response status code is 200 OK", function () {
    pm.have.status(200);
});

The above test script checks if the response time is below 200 milliseconds and if the response status code is 200 OK. The pm.test function is used to define individual test cases, and various assertions like pm.expect and pm.status are used to validate the conditions.

Automating API Workflows with JavaScript

In addition to writing tests, Postman allows users to automate API workflows using JavaScript. This can be achieved by creating scripts in the “Pre-request Script” and “Post-request Script” sections of the request builder. These scripts are executed before and after sending a request, respectively.

The “Pre-request Script” can be used to set up environment variables, modify request headers, or perform any necessary setup actions. Similarly, the “Post-request Script” can be utilized to extract data from the response, save it as environment variables, or perform any post-processing tasks.

Conclusion

In summary, while Postman itself is not a scripting language, it utilizes JavaScript for writing tests and automating API workflows. JavaScript’s flexibility and extensive capabilities make it an ideal choice for interacting with APIs using Postman. By leveraging JavaScript in Postman, developers can ensure the reliability and functionality of their APIs.