Global variables in Postman

Introduction

Global variables let you save values that you can use in many tests or requests. This helps avoid repeating the same data over and over.

You want to store a user token to use in many API requests.

You need to save a base URL that is used in all your requests.

You want to share data between different test scripts in Postman.

You want to keep a value that changes during testing and use it later.

You want to avoid hardcoding values in multiple places.

Syntax

Postman

// Set a global variable
pm.globals.set('variableName', 'value');

// Get a global variable
let value = pm.globals.get('variableName');

// Remove a global variable
pm.globals.unset('variableName');

// Clear all global variables
pm.globals.clear();

Use pm.globals.set to save a value globally.

Use pm.globals.get to read the saved value.

Examples

This saves 'abc123' as 'authToken' globally and then reads it back to print.

Postman

pm.globals.set('authToken', 'abc123');
let token = pm.globals.get('authToken');
console.log(token);

This removes the 'authToken' global variable. Getting it after returns undefined.

Postman

pm.globals.unset('authToken');
let token = pm.globals.get('authToken');
console.log(token);

This clears all global variables and prints an empty object.

Postman

pm.globals.clear();
console.log(pm.globals.toObject());

Sample Program

This script saves a user ID globally and then checks if it was saved correctly in a test.

Postman

// Set a global variable
pm.globals.set('userId', 'user_001');

// Use the global variable in a test
let userId = pm.globals.get('userId');
pm.test('User ID is set correctly', function () {
    pm.expect(userId).to.eql('user_001');
});

Important Notes

Global variables are shared across all collections and requests in Postman.

Be careful not to store sensitive data in global variables if sharing your workspace.

Use environment variables if you want variables specific to a project or environment.

Summary

Global variables store data accessible everywhere in Postman.

Use pm.globals.set and pm.globals.get to manage them.

They help avoid repeating values and share data between tests.

Practice

1. What is the main purpose of global variables in Postman?

easy

A. To store data accessible across all requests and tests

B. To store data only for the current request

C. To create temporary variables that disappear after one test

D. To define environment-specific settings

Solution

1. Step 1: Understand global variable scope

   Global variables in Postman are accessible everywhere, across all requests and tests.

2. Step 2: Compare with other variable types

   Unlike environment or local variables, global variables persist and are shared globally.

3. Final Answer:

   To store data accessible across all requests and tests -> Option A

4. Quick Check:

   Global variables = accessible everywhere [OK]

Hint: Global variables are shared everywhere in Postman [OK]

Common Mistakes:

• Confusing global variables with environment variables
• Thinking global variables are temporary
• Assuming global variables are request-specific

2. Which of the following is the correct syntax to set a global variable named token with value abc123 in Postman?

easy

A. pm.globals.add('token', 'abc123');

B. pm.global.set('token', 'abc123');

C. pm.globals.set('token', 'abc123');

D. pm.globalVariables.set('token', 'abc123');

Solution

1. Step 1: Recall correct Postman global variable syntax

   The correct method to set a global variable is pm.globals.set(key, value).

2. Step 2: Identify the correct object and method

   Only pm.globals.set('token', 'abc123'); uses pm.globals.set correctly with proper quotes and parameters.

3. Final Answer:

   pm.globals.set('token', 'abc123'); -> Option C

4. Quick Check:

   Use pm.globals.set to set global variables [OK]

Hint: Use pm.globals.set('key', 'value') to set globals [OK]

Common Mistakes:

• Using pm.global instead of pm.globals
• Using .add instead of .set method
• Incorrect object names like pm.globalVariables

3. Consider this Postman test script:

pm.globals.set('userId', '42');
const id = pm.globals.get('userId');
console.log(id);

What will be printed in the Postman console?

medium

A. undefined

B. 42

C. userId

D. null

Solution

1. Step 1: Set global variable 'userId' to '42'

   The first line stores the string '42' in the global variable named 'userId'.

2. Step 2: Retrieve and log the global variable

   The second line gets the value of 'userId' which is '42', then logs it.

3. Final Answer:

   42 -> Option B

4. Quick Check:

   pm.globals.get('userId') returns '42' [OK]

Hint: pm.globals.get returns the stored value [OK]

Common Mistakes:

• Expecting variable name instead of value
• Confusing undefined with null
• Forgetting to set the variable before getting

4. You wrote this Postman script to set a global variable:

pm.globals.set(userId, '100');

But it throws an error. What is the problem?

medium

A. The variable name userId should be a string in quotes

B. pm.globals.set cannot set numeric values

C. pm.globals.set requires three arguments

D. Global variables cannot be set inside scripts

Solution

1. Step 1: Check the syntax of pm.globals.set

   The first argument must be a string key, so it should be quoted like 'userId'.

2. Step 2: Identify the error cause

   Without quotes, userId is treated as an undefined variable causing an error.

3. Final Answer:

   The variable name userId should be a string in quotes -> Option A

4. Quick Check:

   Keys must be strings in pm.globals.set [OK]

Hint: Always quote variable names in pm.globals.set [OK]

Common Mistakes:

• Not quoting the key name
• Thinking pm.globals.set needs more arguments
• Believing global variables can't be set in scripts

5. You want to share a session token between multiple requests in Postman using global variables. Which sequence correctly sets and retrieves the token?

// Request 1
pm.globals.set('sessionToken', 'xyz789');

// Request 2
const token = pm.globals.get('sessionToken');
console.log(token);

hard

A. You must use environment variables instead of global variables

B. You need to pass the token as a parameter, not use globals

C. pm.globals.get cannot retrieve variables set in other requests

D. This sequence correctly shares the token globally

Solution

1. Step 1: Set global variable in first request

   The first request sets 'sessionToken' globally using pm.globals.set.

2. Step 2: Retrieve global variable in second request

   The second request gets the same 'sessionToken' using pm.globals.get and logs it.

3. Final Answer:

   This sequence correctly shares the token globally -> Option D

4. Quick Check:

   Global variables share data across requests [OK]

Hint: Set in one request, get in another using pm.globals [OK]

Common Mistakes:

• Thinking globals can't share data between requests
• Confusing environment and global variables
• Trying to pass token manually instead of using variables