How to Use pm.sendRequest in Postman for API Testing

Use pm.sendRequest in Postman scripts to send HTTP requests programmatically during test execution. It takes a request object and a callback function to handle the response, enabling chaining or conditional API calls within your tests.

Syntax

The pm.sendRequest function requires two main parts: a request configuration object and a callback function. The request object defines the HTTP method, URL, headers, and body. The callback function receives the response to perform assertions or further actions.

javascript

pm.sendRequest({
  url: 'https://api.example.com/data',
  method: 'GET',
  header: {
    'Content-Type': 'application/json'
  },
  body: {
    mode: 'raw',
    raw: JSON.stringify({ key: 'value' })
  }
}, function (err, res) {
  // handle response here
});

Example

This example sends a GET request to a public API and checks if the response status is 200. It demonstrates how to use pm.sendRequest inside a test script to make a secondary API call and validate its response.

javascript

pm.sendRequest({
  url: 'https://jsonplaceholder.typicode.com/posts/1',
  method: 'GET'
}, function (err, res) {
  pm.test('Response status is 200', function () {
    pm.expect(err).to.be.null;
    pm.expect(res).to.have.property('code', 200);
  });
  pm.test('Response has userId', function () {
    const jsonData = res.json();
    pm.expect(jsonData).to.have.property('userId');
  });
});

Output

PASS  Response status is 200
PASS  Response has userId

Common Pitfalls

• Not handling the asynchronous nature of pm.sendRequest can cause tests to finish before the request completes.
• Forgetting to check for errors in the callback leads to false positives.
• Incorrect request object structure, such as missing method or malformed body, causes request failures.

Always include error checks and use pm.expect inside the callback to ensure proper test validation.

javascript

/* Wrong way: Missing error check and assertions outside callback */
pm.sendRequest({ url: 'https://jsonplaceholder.typicode.com/posts/1', method: 'GET' });
pm.test('Check status', () => {
  pm.expect(pm.response.code).to.eql(200); // This will fail because pm.response is not from sendRequest
});

/* Right way: Use assertions inside callback and check errors */
pm.sendRequest({ url: 'https://jsonplaceholder.typicode.com/posts/1', method: 'GET' }, (err, res) => {
  pm.test('Status is 200', () => {
    pm.expect(err).to.be.null;
    pm.expect(res).to.have.property('code', 200);
  });
});

Quick Reference

Here is a quick summary of key points when using pm.sendRequest:

Feature	Description
Request Object	Defines URL, method, headers, and body for the HTTP request.
Callback Function	Receives error and response to handle results and assertions.
Asynchronous	Runs asynchronously; assertions must be inside the callback.
Use Cases	Chaining requests, conditional logic, or fetching data during tests.
Error Handling	Always check err in the callback to catch request failures.

Key Takeaways

Use pm.sendRequest to send HTTP requests programmatically within Postman scripts.

Always place assertions inside the callback function to handle asynchronous responses correctly.

Check for errors in the callback to avoid false test results.

Define the request object clearly with method, URL, headers, and body as needed.

Use pm.sendRequest for chaining API calls or conditional testing scenarios.