Environment variables in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are environment variables in Postman?

Environment variables in Postman are placeholders that store values you can reuse in your requests, like URLs or tokens. They help you run tests in different setups without changing the request manually.

beginner

How do you create an environment variable in Postman?

You create an environment variable by opening the Environment quick look, clicking 'Add', then entering a variable name and value. Save it to use in your requests with {{variable_name}} syntax.

beginner

Why use environment variables instead of hardcoding values?

Using environment variables lets you switch between different setups easily, like testing on development or production servers, without changing each request manually. It saves time and reduces errors.

beginner

How do you reference an environment variable in a Postman request?

You reference an environment variable by wrapping its name in double curly braces, like {{variable_name}}. Postman replaces this with the variable's value when sending the request.

intermediate

What happens if an environment variable is not set in Postman?

If an environment variable is not set, Postman will send the request with the variable name as is (like {{variable_name}}), which usually causes the request to fail or behave unexpectedly.

What is the correct syntax to use an environment variable named 'baseUrl' in a Postman request?

A [baseUrl]

B {{baseUrl}}

C $baseUrl

D <baseUrl>

In Postman, environment variables are referenced using double curly braces like {{baseUrl}}.

Why should you use environment variables in Postman?

A To reuse values and switch environments easily

B To hardcode values permanently

C To slow down requests

D To avoid saving requests

Environment variables let you reuse values and switch between environments like development and production without changing requests manually.

Where do you manage environment variables in Postman?

A In the Headers tab

B In the Body tab

C In the Console

D In the Environment quick look or Manage Environments

You manage environment variables in Postman using the Environment quick look or the Manage Environments section.

What happens if you use an environment variable that is not defined?

A Postman replaces it with an empty string

B Postman ignores the request

C Postman replaces it with the variable name as is

D Postman throws an error and stops

If an environment variable is not defined, Postman sends the request with the variable name like {{variable_name}}, which usually causes errors.

Can environment variables store sensitive data like API keys in Postman?

A Yes, but use Postman's secret environments for security

B No, environment variables cannot store sensitive data

C Yes, and they are always encrypted

D No, you must hardcode sensitive data

Environment variables can store sensitive data, but it's best to use Postman's secret environments or other secure methods to protect them.

Explain what environment variables are in Postman and why they are useful.

Think about how you can test the same API on different servers without changing each request.

Describe how to create and use an environment variable in a Postman request.

Focus on the steps from creating to referencing the variable.

Practice

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

easy

A. To store reusable values that can be used across multiple requests

B. To write test assertions for API responses

C. To create new API endpoints automatically

D. To generate random data for requests

Solution

1. Step 1: Understand environment variables role

   Environment variables hold values like URLs or tokens that you reuse in many requests.

2. Step 2: Compare with other options

   Writing tests or generating data are different features, not the main use of environment variables.

3. Final Answer:

   To store reusable values that can be used across multiple requests -> Option A

4. Quick Check:

   Environment variables = reusable values [OK]

Hint: Environment variables hold reusable data for requests [OK]

Common Mistakes:

• Confusing environment variables with test scripts
• Thinking environment variables create endpoints
• Assuming they generate random data automatically

2. Which of the following is the correct way to set an environment variable named token to abc123 in a Postman test script?

easy

A. pm.environment.set('token', 'abc123');

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

C. pm.environment.get('token', 'abc123');

D. pm.setEnvironment('token', 'abc123');

Solution

1. Step 1: Identify correct method to set environment variable

   Postman uses pm.environment.set(key, value) to set environment variables.

2. Step 2: Check other options for correctness

   pm.variables.set sets local variables, pm.environment.get is for getting values, and pm.setEnvironment is not a valid method.

3. Final Answer:

   pm.environment.set('token', 'abc123'); -> Option A

4. Quick Check:

   Set env var = pm.environment.set(key, value) [OK]

Hint: Use pm.environment.set() to assign environment variables [OK]

Common Mistakes:

• Using pm.environment.get() to set variables
• Confusing pm.variables.set() with environment variables
• Using non-existent methods like pm.setEnvironment()

3. Given the following Postman test script, what will be the value of the environment variable userId after execution?

pm.environment.set('userId', 10);
pm.environment.set('userId', Number(pm.environment.get('userId')) + 5);

medium

A. Error

B. 10

C. undefined

D. 15

Solution

1. Step 1: Analyze first line setting userId

   The first line sets userId to 10.

2. Step 2: Analyze second line updating userId

   The second line gets current userId (10), adds 5, and sets it back, so userId becomes 15.

3. Final Answer:

   15 -> Option D

4. Quick Check:

   10 + 5 = 15 [OK]

Hint: Get then set adds values correctly [OK]

Common Mistakes:

• Assuming variable stays 10 after second line
• Thinking get returns undefined initially
• Expecting a runtime error

4. You wrote this Postman script to remove an environment variable sessionId but it does not work:

pm.environment.delete('sessionId');

What is the correct way to delete an environment variable?

medium

A. pm.environment.remove('sessionId');

B. pm.environment.unset('sessionId');

C. pm.environment.clear('sessionId');

D. pm.environment.deleteVariable('sessionId');

Solution

1. Step 1: Identify correct method to delete environment variable

   Postman uses pm.environment.unset(key) to remove environment variables.

2. Step 2: Check why original code fails

   pm.environment.delete() is not a valid method, so it does not remove the variable.

3. Final Answer:

   pm.environment.unset('sessionId'); -> Option B

4. Quick Check:

   Delete env var = pm.environment.unset(key) [OK]

Hint: Use pm.environment.unset() to remove variables [OK]

Common Mistakes:

• Using pm.environment.delete() which is invalid
• Trying pm.environment.remove() or clear() which don't exist for single variables
• Confusing with non-existent deleteVariable()

5. You want to run the same Postman collection on two different servers: dev and prod. Which is the best way to use environment variables to switch the base URL without changing the request code?

hard

A. Use global variables to store the URLs and change them before each run

B. Hardcode the server URL in each request and manually change it before running

C. Create two environments with a variable baseUrl set to each server URL, then select the environment before running

D. Write separate collections for dev and prod with different URLs

Solution

1. Step 1: Understand environment variables for different setups

   Creating separate environments with baseUrl variables allows easy switching without code changes.

2. Step 2: Compare other options

   Hardcoding or separate collections cause manual errors and duplication; global variables are less flexible for multiple setups.

3. Final Answer:

   Create two environments with a variable baseUrl set to each server URL, then select the environment before running -> Option C

4. Quick Check:

   Use environments to switch URLs easily [OK]

Hint: Use separate environments with baseUrl variables [OK]

Common Mistakes:

• Hardcoding URLs in requests
• Using global variables instead of environments
• Creating duplicate collections for each server