Conditional request execution (setNextRequest) in Postman - Build an Automation Script

Conditional execution of Postman requests using setNextRequest

Preconditions (2)

Step 1: Send the 'Login' request with valid credentials.

Step 2: Check the 'success' field in the response JSON.

Step 3: If 'success' is true, execute the 'Get User Data' request next.

Step 4: If 'success' is false, do not execute any further requests.

✅ Expected Result: If login is successful, 'Get User Data' request runs next. If login fails, no further requests run.

Automation Requirements - Postman Sandbox JavaScript

Assertions Needed:

Verify 'success' field is present and boolean in 'Login' response.

Verify 'Get User Data' request runs only if 'success' is true.

Verify no further requests run if 'success' is false.

Best Practices:

Use pm.response.json() to parse JSON response safely.

Use pm.setNextRequest() to control request flow conditionally.

Avoid hardcoding request names; use exact request names as in collection.

Add clear console logs for debugging flow.

Automated Solution

Postman

pm.test('Check login success field exists and is boolean', () => {
    const jsonData = pm.response.json();
    pm.expect(jsonData).to.have.property('success');
    pm.expect(jsonData.success).to.be.a('boolean');
});

const jsonData = pm.response.json();

if (jsonData.success === true) {
    console.log('Login successful, proceeding to Get User Data request');
    pm.setNextRequest('Get User Data');
} else {
    console.log('Login failed, stopping further requests');
    pm.setNextRequest(null);
}

This script runs in the Tests tab of the 'Login' request in Postman.

First, it checks that the response JSON has a success field and that it is a boolean. This ensures the response is as expected.

Then, it reads the success value. If true, it uses pm.setNextRequest('Get User Data') to tell Postman to run the 'Get User Data' request next.

If success is false, it calls pm.setNextRequest(null) to stop running any further requests.

Console logs help track the flow when running the collection.

Common Mistakes - 4 Pitfalls

Using incorrect request name in pm.setNextRequest

Not parsing response JSON before accessing fields

{'mistake': "Not handling the case when 'success' field is missing", 'why_bad': 'If the field is missing, the script may throw an error or behave unpredictably.', 'correct_approach': 'Add assertions to check the presence and type of the field before using it.'}

Not calling pm.setNextRequest(null) to stop requests on failure

Bonus Challenge

Now add data-driven testing with 3 different login credentials to test success and failure scenarios.

Show Hint

Practice

1. What is the main purpose of pm.setNextRequest() in Postman?

easy

A. To decide which request runs next based on a condition

B. To send the current request multiple times automatically

C. To stop the entire collection run immediately

D. To reset all environment variables to default values

Solution

1. Step 1: Understand the function of pm.setNextRequest()

   This function controls the flow of requests by specifying which request should run next.

2. Step 2: Compare with other options

   Options B, C, and D describe different actions not related to controlling the next request.

3. Final Answer:

   To decide which request runs next based on a condition -> Option A

4. Quick Check:

   pm.setNextRequest() controls next request execution [OK]

Hint: Remember: setNextRequest controls the next request flow [OK]

Common Mistakes:

• Thinking it repeats the current request
• Confusing it with stopping the collection run
• Assuming it resets variables

2. Which of the following is the correct syntax to set the next request named "Login" in a Postman test script?

easy

A. pm.setNextRequest(Login);

B. pm.setNextRequest("Login");

C. pm.setNextRequest('Login');

D. pm.setNextRequest(Login')

Solution

1. Step 1: Check the syntax for string argument

   The request name must be passed as a string in quotes. Both single or double quotes are valid, but must be paired correctly.

2. Step 2: Identify correct option

   pm.setNextRequest("Login"); uses double quotes correctly. pm.setNextRequest('Login'); also uses single quotes correctly. Both are valid syntaxes. pm.setNextRequest(Login); lacks quotes, causing a syntax error. pm.setNextRequest(Login') has mismatched quotes.

3. Final Answer:

   pm.setNextRequest("Login"); -> Option B

4. Quick Check:

   Request name must be a quoted string [OK]

Hint: Always quote request names in setNextRequest() [OK]

Common Mistakes:

• Forgetting quotes around request name
• Mismatched or missing quotes
• Omitting semicolon at line end

3. Consider this test script in Postman after a request named "CheckStatus":

if (pm.response.code === 200) {
    pm.setNextRequest('ProcessData');
} else {
    pm.setNextRequest('ErrorHandler');
}

If the response code is 404, which request runs next?

medium

A. ErrorHandler

B. ProcessData

C. CheckStatus

D. No next request runs

Solution

1. Step 1: Analyze the condition

   The script checks if response code is 200. If true, it sets next request to 'ProcessData'. Otherwise, it sets to 'ErrorHandler'.

2. Step 2: Apply the response code 404

   Since 404 is not 200, the else block runs, setting next request to 'ErrorHandler'.

3. Final Answer:

   ErrorHandler -> Option A

4. Quick Check:

   404 ≠ 200, so next request = ErrorHandler [OK]

Hint: If condition false, else block sets next request [OK]

Common Mistakes:

• Assuming 404 triggers the if block
• Thinking current request repeats
• Ignoring else block logic

4. You wrote this test script in Postman:

if (pm.response.code = 200) {
    pm.setNextRequest('NextStep');
} else {
    pm.setNextRequest('Stop');
}

What is the problem with this script?

medium

A. Request names should not be in quotes

B. Missing semicolon after pm.response.code

C. pm.setNextRequest cannot be used inside if statements

D. Using assignment (=) instead of comparison (===) in the if condition

Solution

1. Step 1: Identify the if condition error

   The condition uses single equals (=), which assigns 200 to pm.response.code instead of comparing it.

2. Step 2: Understand consequences

   This causes a bug: the if condition always evaluates to true, and response code is overwritten.

3. Final Answer:

   Using assignment (=) instead of comparison (===) in the if condition -> Option D

4. Quick Check:

   Use === for comparison, not = [OK]

Hint: Use === for comparison, not = assignment [OK]

Common Mistakes:

• Confusing = with === in conditions
• Removing quotes from request names
• Thinking setNextRequest can't be conditional

5. You want to create a Postman flow where if a variable userExists is true, the next request is "GetUserData", else the flow stops. Which script correctly implements this in the test tab?

hard

A. if (pm.variables.get('userExists') === true) {
pm.setNextRequest('GetUserData');
} else {
pm.setNextRequest(null);
}

B. if (pm.variables.get('userExists') == 'true') {
pm.setNextRequest('GetUserData');
} else {
pm.setNextRequest('Stop');
}

C. if (pm.variables.get('userExists')) {
pm.setNextRequest('GetUserData');
} else {
pm.setNextRequest(null);
}

D. if (pm.variables.get('userExists') === 'true') {
pm.setNextRequest('GetUserData');
} else {
pm.setNextRequest(null);
}

Solution

1. Step 1: Understand variable type and condition

   pm.variables.get returns a string or boolean depending on how set. Using it directly in if checks truthiness correctly.

2. Step 2: Check stopping the flow

   Setting pm.setNextRequest(null) stops the collection run, which matches the requirement to stop if userExists is false.

3. Step 3: Evaluate options

   if (pm.variables.get('userExists')) { pm.setNextRequest('GetUserData'); } else { pm.setNextRequest(null); } uses direct truthiness check and null to stop, which is correct. Options A and C compare strictly to boolean or string which may fail if variable type differs. if (pm.variables.get('userExists') == 'true') { pm.setNextRequest('GetUserData'); } else { pm.setNextRequest('Stop'); } tries to set next request to 'Stop' which is not a request name and won't stop the flow.

4. Final Answer:

   if (pm.variables.get('userExists')) { pm.setNextRequest('GetUserData'); } else { pm.setNextRequest(null); } -> Option C

5. Quick Check:

   Use truthy check and null to stop flow [OK]

Hint: Use null in setNextRequest to stop flow [OK]

Common Mistakes:

• Comparing variable to string 'true' instead of boolean
• Setting next request to a non-existent name to stop
• Not using null to stop the collection run