Bearer token in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Bearer token in API testing?

A Bearer token is a type of access token used in API testing to authorize requests. It is sent in the HTTP header to prove the client has permission to access the resource.

beginner

How do you add a Bearer token in Postman?

In Postman, go to the Authorization tab, select 'Bearer Token' as the type, and paste your token in the Token field. Postman will add it to the request header automatically.

beginner

Why should Bearer tokens be kept secret?

Bearer tokens grant access to protected resources. If someone else gets your token, they can use it to access your data or services without permission, like having a key to your house.

beginner

What HTTP header is used to send a Bearer token?

The 'Authorization' header is used. It looks like: Authorization: Bearer <token> where <token> is your actual token string.

beginner

What happens if you send an API request without a valid Bearer token?

The server usually responds with an error like 401 Unauthorized, meaning you are not allowed to access the resource without proper authentication.

In Postman, where do you add a Bearer token for API requests?

A Authorization tab

B Headers tab

C Body tab

D Params tab

Bearer tokens are added in the Authorization tab where you select 'Bearer Token' type.

What does the 'Bearer' keyword in the Authorization header mean?

A It is the password of the client

B It is the username of the client

C It indicates the type of token used for authentication

D It is the API endpoint

The 'Bearer' keyword tells the server that the following string is a token used for authentication.

What HTTP status code usually means a missing or invalid Bearer token?

A 401 Unauthorized

B 200 OK

C 404 Not Found

D 500 Internal Server Error

401 Unauthorized means the request lacks valid authentication credentials.

Why is it important to keep Bearer tokens secure?

A Because they expire quickly

B Because they are used for logging only

C Because they are public information

D Because they allow access to protected resources

Bearer tokens grant access to resources, so if leaked, unauthorized users can misuse them.

Which header contains the Bearer token in an API request?

A Content-Type

B Authorization

C Accept

D User-Agent

The Authorization header carries the Bearer token.

Explain what a Bearer token is and how it is used in API testing with Postman.

Think about how you prove your identity to access a service.

Describe the security risks of exposing a Bearer token and best practices to protect it.

Imagine someone stealing your house key.

Practice

1. What is the correct way to include a Bearer token in a Postman request header?

easy

A. Add a query parameter named 'token' with the token value

B. Set the Authorization header to 'Bearer <token>'

C. Include the token in the request body as JSON

D. Set a cookie named 'Bearer' with the token value

Solution

1. Step 1: Understand Bearer token usage in headers

   Bearer tokens are sent in the Authorization header to prove identity.

2. Step 2: Identify correct header format

   The header must be 'Authorization: Bearer <token>' exactly.

3. Final Answer:

   Set the Authorization header to 'Bearer <token>' -> Option B

4. Quick Check:

   Authorization header = Bearer token [OK]

Hint: Always use Authorization header with 'Bearer ' prefix [OK]

Common Mistakes:

• Putting token in query parameters instead of header
• Sending token in request body instead of header
• Using cookie instead of Authorization header

2. Which of the following is the correct syntax to add a Bearer token in Postman headers?

easy

A. "Auth": "Bearer <token>"

B. "Authorization": "Token <token>"

C. "Authorization": "Bearer <token>"

D. "Authorization": "Basic <token>"

Solution

1. Step 1: Recall correct header key and value format

   The header key must be 'Authorization' and the value must start with 'Bearer '.

2. Step 2: Match the exact syntax

   Only "Authorization": "Bearer <token>" uses 'Authorization' and 'Bearer <token>' correctly.

3. Final Answer:

   "Authorization": "Bearer <token>" -> Option C

4. Quick Check:

   Authorization = Bearer token syntax [OK]

Hint: Remember header key is 'Authorization' and value starts with 'Bearer ' [OK]

Common Mistakes:

• Using 'Token' instead of 'Bearer' prefix
• Using 'Auth' instead of 'Authorization' header
• Confusing 'Basic' auth with Bearer token

3. Given this Postman test script snippet, what will be the value of the Authorization header sent?

pm.request.headers.add({key: 'Authorization', value: `Bearer ${pm.environment.get('token')}`});

medium

A. Authorization: Bearer <token_value_from_environment>

B. Authorization: Token <token_value_from_environment>

C. Authorization: Bearer undefined

D. Authorization: Basic <token_value_from_environment>

Solution

1. Step 1: Understand the code usage of environment variable

   The code uses pm.environment.get('token') to get the token value from environment variables.

2. Step 2: Analyze the header value construction

   The header value is 'Bearer ' plus the token value from environment, so it will be 'Bearer <token_value_from_environment>'.

3. Final Answer:

   Authorization: Bearer <token_value_from_environment> -> Option A

4. Quick Check:

   Header value = 'Bearer ' + environment token [OK]

Hint: Check environment variable usage inside template literals [OK]

Common Mistakes:

• Assuming token is 'undefined' if environment variable missing
• Using 'Token' instead of 'Bearer' prefix
• Confusing Basic auth with Bearer token

4. You added a Bearer token in Postman but the API returns 401 Unauthorized. What is the most likely mistake?

medium

A. The Authorization header is missing the 'Bearer ' prefix

B. The token is placed in the request body instead of headers

C. The Content-Type header is set to 'application/json'

D. The token is expired or invalid

Solution

1. Step 1: Check common causes of 401 Unauthorized with Bearer tokens

   401 usually means token is missing, malformed, or invalid/expired.

2. Step 2: Identify the most likely cause given the token is added

   If the token is added correctly but still 401, it is likely expired or invalid.

3. Final Answer:

   The token is expired or invalid -> Option D

4. Quick Check:

   401 Unauthorized often means invalid token [OK]

Hint: Check token validity if 401 despite correct header [OK]

Common Mistakes:

• Forgetting 'Bearer ' prefix in Authorization header
• Placing token in body instead of header
• Assuming Content-Type affects authorization

5. You want to automate testing of an API that requires a Bearer token which expires every hour. Which approach is best to handle this in Postman?

hard

A. Use a Pre-request Script to fetch a new token and set it dynamically before each request

B. Manually update the token in environment variables before each test run

C. Hardcode the token in the Authorization header and ignore expiration

D. Remove the Authorization header to avoid token expiration errors

Solution

1. Step 1: Understand token expiration and automation needs

   Since the token expires hourly, manual updates are inefficient and error-prone.

2. Step 2: Choose dynamic token fetching in Pre-request Script

   Using a Pre-request Script to get a fresh token before each request automates the process and avoids failures.

3. Final Answer:

   Use a Pre-request Script to fetch a new token and set it dynamically before each request -> Option A

4. Quick Check:

   Automate token refresh with Pre-request Script [OK]

Hint: Automate token refresh with Pre-request Script [OK]

Common Mistakes:

• Manually updating tokens wastes time and causes errors
• Hardcoding tokens ignores expiration and causes failures
• Removing Authorization header breaks authentication