Delay between requests in Postman - Build an Automation Script

Add delay between API requests in Postman collection

Preconditions (2)

Step 1: Open the Postman collection with multiple requests

Step 2: Select the first request in the collection

Step 3: Go to the Tests tab of the first request

Step 4: Add a script to pause execution for 3 seconds before the next request runs

Step 5: Save the script

Step 6: Run the collection using the Collection Runner

Step 7: Observe that there is a 3-second delay between the first and second request

✅ Expected Result: The collection runner pauses for 3 seconds between the first and second requests, delaying the next request execution as scripted.

Automation Requirements - Postman scripting (JavaScript)

Assertions Needed:

Verify that the delay script executes without errors

Verify that the delay causes a pause of approximately 3 seconds between requests

Best Practices:

Use pm.setNextRequest(null) to control request flow if needed

Use setTimeout or async/await with Promises for delay

Keep scripts simple and readable

Avoid hardcoding delays longer than necessary

Automated Solution

Postman

pm.test('Delay 3 seconds before next request', function(done) {
    setTimeout(() => {
        done();
    }, 3000);
});

This script is added in the Tests tab of the first request. It uses pm.test with a callback done to create an asynchronous test. Inside, setTimeout waits for 3000 milliseconds (3 seconds) before calling done(), which tells Postman to continue to the next request. This effectively adds a 3-second delay between requests during collection run.

This approach is simple and uses Postman's built-in asynchronous test handling to pause execution without blocking the UI.

Common Mistakes - 3 Pitfalls

Using synchronous loops or blocking code to create delay

Placing delay script in Pre-request Script tab instead of Tests tab

Not calling done() in asynchronous test, causing timeout

Bonus Challenge

Now add data-driven testing with 3 different delay durations (1s, 3s, 5s) for the delay between requests

Show Hint

Practice

1. What is the main purpose of adding a delay between requests in Postman?

easy

A. To change the request URL dynamically

B. To speed up the test execution

C. To skip some requests automatically

D. To simulate real user behavior and avoid server overload

Solution

1. Step 1: Understand delay usage in Postman

   Delays are used to mimic real user wait times and prevent sending too many requests too fast.

2. Step 2: Identify the correct purpose

   Speeding up tests or skipping requests are not related to delays; delays help simulate real scenarios and protect servers.

3. Final Answer:

   To simulate real user behavior and avoid server overload -> Option D

4. Quick Check:

   Delay purpose = simulate real use and avoid overload [OK]

Hint: Delays mimic real users and protect servers from overload [OK]

Common Mistakes:

• Thinking delays speed up tests
• Confusing delay with skipping requests
• Assuming delay changes request data

2. Which of the following is the correct way to add a 2-second delay between requests in Postman using JavaScript?

easy

A. delay(2000); postman.setNextRequest('Request2');

B. postman.setNextRequest('Request2', 2000);

C. setTimeout(() => postman.setNextRequest('Request2'), 2000);

D. setTimeout(postman.setNextRequest('Request2'), 2000);

Solution

1. Step 1: Recall correct setTimeout syntax

   setTimeout takes a function and delay in milliseconds: setTimeout(function, delay).

2. Step 2: Check usage with postman.setNextRequest

   postman.setNextRequest must be called inside a function passed to setTimeout to delay execution.

3. Final Answer:

   setTimeout(() => postman.setNextRequest('Request2'), 2000); -> Option C

4. Quick Check:

   Use setTimeout with function and delay [OK]

Hint: Wrap setNextRequest in a function inside setTimeout [OK]

Common Mistakes:

• Passing setNextRequest call directly to setTimeout
• Using non-existent delay function
• Trying to pass delay as second argument to setNextRequest

3. Given this Postman test script snippet, what will happen?

setTimeout(() => postman.setNextRequest('Login'), 3000);
console.log('Request scheduled');

medium

A. The 'Login' request will run immediately, and 'Request scheduled' logs after 3 seconds

B. 'Request scheduled' logs immediately, and 'Login' request runs after 3 seconds

C. Both 'Login' request and log happen immediately

D. Neither 'Login' request nor log will run

Solution

1. Step 1: Understand setTimeout behavior

   setTimeout delays the function call (postman.setNextRequest) by 3000 ms, but console.log runs immediately.

2. Step 2: Determine order of execution

   console.log('Request scheduled') runs first; after 3 seconds, the 'Login' request is set to run next.

3. Final Answer:

   'Request scheduled' logs immediately, and 'Login' request runs after 3 seconds -> Option B

4. Quick Check:

   console.log immediate, setNextRequest delayed [OK]

Hint: console.log runs immediately; setNextRequest delayed by setTimeout [OK]

Common Mistakes:

• Assuming setNextRequest runs immediately
• Thinking console.log waits for delay
• Confusing order of asynchronous calls

4. You wrote this Postman script to delay the next request by 1 second, but the delay does not work. What is wrong?

setTimeout(postman.setNextRequest('NextRequest'), 1000);

medium

A. postman.setNextRequest should be inside a function passed to setTimeout

B. Delay time should be in seconds, not milliseconds

C. setTimeout cannot be used in Postman scripts

D. postman.setNextRequest does not accept request names

Solution

1. Step 1: Analyze setTimeout usage

   setTimeout expects a function as first argument, but here postman.setNextRequest is called immediately.

2. Step 2: Correct usage for delay

   Wrap postman.setNextRequest call inside a function (e.g., arrow function) to delay execution properly.

3. Final Answer:

   postman.setNextRequest should be inside a function passed to setTimeout -> Option A

4. Quick Check:

   Pass function to setTimeout, not direct call [OK]

Hint: Wrap setNextRequest call in a function for setTimeout delay [OK]

Common Mistakes:

• Passing direct call instead of function to setTimeout
• Confusing milliseconds with seconds
• Believing setTimeout is unsupported in Postman

5. You want to run three requests in sequence with a 1-second delay between each in Postman. Which script correctly implements this in the Tests tab of the first request?

hard

A. setTimeout(() => { postman.setNextRequest('Request2'); setTimeout(() => postman.setNextRequest('Request3'), 1000); }, 1000);

B. setTimeout(() => postman.setNextRequest('Request2'), 1000);

C. postman.setNextRequest('Request2'); setTimeout(() => postman.setNextRequest('Request3'), 1000);

D. postman.setNextRequest('Request2'); postman.setNextRequest('Request3');

Solution

1. Step 1: Understand sequential delays

   Each request must be delayed before triggering the next; nested setTimeout calls create sequential delays.

2. Step 2: Analyze options

   setTimeout(() => { postman.setNextRequest('Request2'); setTimeout(() => postman.setNextRequest('Request3'), 1000); }, 1000); nests setTimeout calls to delay Request2 by 1s, then Request3 by another 1s, correctly sequencing requests with delays.

3. Final Answer:

   setTimeout(() => { postman.setNextRequest('Request2'); setTimeout(() => postman.setNextRequest('Request3'), 1000); }, 1000); -> Option A

4. Quick Check:

   Nested setTimeouts create sequential delays [OK]

Hint: Use nested setTimeouts to delay multiple requests sequentially [OK]

Common Mistakes:

• Calling setNextRequest multiple times without delay
• Not nesting delays causing immediate requests
• Assuming one setTimeout delays all requests