Global variables in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a global variable in Postman?

A global variable in Postman is a value stored that can be accessed by any request or script within the Postman workspace. It helps share data across multiple requests.

beginner

How do you set a global variable in a Postman test script?

You use pm.globals.set('variableName', 'value') to create or update a global variable in Postman.

beginner

How can you retrieve a global variable's value in Postman scripts?

Use pm.globals.get('variableName') to get the value of a global variable in Postman scripts.

intermediate

What is the difference between global variables and environment variables in Postman?

Global variables are accessible across all environments and requests, while environment variables are specific to a selected environment and help manage different setups like dev, test, or prod.

intermediate

Why should you be careful when using global variables in Postman?

Because global variables are shared across all requests and environments, accidental changes can affect many tests. It's best to use them only when needed and clean up after tests.

Which Postman method sets a global variable?

A pm.globals.set('name', 'value')

B pm.environment.set('name', 'value')

C pm.variables.set('name', 'value')

D pm.request.set('name', 'value')

pm.globals.set() is used to set global variables accessible across all requests.

How do you access a global variable's value in Postman?

A pm.collection.get('variableName')

B pm.environment.get('variableName')

C pm.request.get('variableName')

D pm.globals.get('variableName')

pm.globals.get() retrieves the value of a global variable.

What is a key difference between global and environment variables in Postman?

A Global variables cannot be changed during runtime.

B Environment variables are shared globally; global variables are environment-specific.

C Global variables are shared across all environments; environment variables are environment-specific.

D Environment variables are only for authentication.

Global variables are accessible everywhere; environment variables depend on the selected environment.

Why might overusing global variables be risky in Postman?

A They slow down the Postman app.

B They can cause unexpected test failures if changed unintentionally.

C They are not saved between sessions.

D They cannot store string values.

Because global variables affect all tests, accidental changes can cause failures.

Which of these is NOT a valid way to clear a global variable in Postman?

A pm.globals.remove('variableName')

B pm.globals.unset('variableName')

C pm.globals.set('variableName', null)

D pm.globals.clear()

pm.globals.remove() is not a valid method; use unset() or clear() instead.

Explain what global variables are in Postman and how they differ from environment variables.

Think about scope and sharing of variables.

Describe how to set, get, and clear a global variable in Postman scripts.

Focus on the Postman scripting API methods.

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