Path parameters in Postman - Build an Automation Script

Verify GET request with path parameters returns correct user data

Preconditions (2)

Step 1: Set the HTTP method to GET

Step 2: Set the request URL to https://api.example.com/users/123 where 123 is the userId path parameter

Step 3: Send the request

Step 4: Observe the response status code and body

✅ Expected Result: Response status code is 200 and response body contains user data for userId 123

Automation Requirements - Postman Tests (JavaScript)

Assertions Needed:

Verify response status code is 200

Verify response body contains userId equal to 123

Best Practices:

Use path parameters properly in the request URL

Write clear and simple test scripts in Postman Tests tab

Use JSON parsing to verify response content

Avoid hardcoding values in multiple places; use variables if possible

Automated Solution

Postman

pm.test('Status code is 200', function () {
    pm.response.to.have.status(200);
});

pm.test('Response has correct userId', function () {
    const jsonData = pm.response.json();
    pm.expect(jsonData.userId).to.eql(123);
});

The first test checks that the HTTP response status code is 200, which means the request was successful.

The second test parses the JSON response body and verifies that the userId field equals 123, matching the path parameter used in the request URL.

This ensures the API returns the correct user data for the given path parameter.

Common Mistakes - 3 Pitfalls

Not replacing the path parameter placeholder with an actual value

Checking response status code without verifying response body

Hardcoding userId in multiple places in the test script

Bonus Challenge

Now add data-driven testing with 3 different userIds: 101, 202, and 303

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