Basic authentication in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Basic Authentication in API testing?

Basic Authentication is a simple method where the client sends a username and password encoded in Base64 in the HTTP header to verify identity.

beginner

How do you set Basic Authentication in Postman?

In Postman, go to the Authorization tab, select 'Basic Auth' type, then enter your username and password. Postman automatically encodes and adds the Authorization header.

intermediate

Why is Base64 encoding not secure for passwords?

Base64 encoding only changes the format of the password; it does not encrypt it. Anyone intercepting the request can decode it easily, so it should be used with HTTPS.

beginner

What HTTP header is used for Basic Authentication?

The 'Authorization' header is used with the value 'Basic ' followed by the Base64 encoded username and password.

beginner

What is a common real-life analogy for Basic Authentication?

It's like showing your ID card at a door guard. You provide your username and password (ID), and the guard checks if you are allowed in.

In Postman, which tab do you use to set Basic Authentication?

A Headers

B Authorization

C Body

D Params

Basic Authentication credentials are set in the Authorization tab in Postman.

What does Basic Authentication send in the HTTP header?

A OAuth token

B Username and password in plain text

C Encrypted token

D Username and password encoded in Base64

Basic Authentication sends username and password encoded in Base64 in the Authorization header.

Why should Basic Authentication be used with HTTPS?

A To encrypt the credentials during transmission

B Because Base64 encoding is secure

C To speed up the request

D To avoid using passwords

Basic Authentication credentials are only Base64 encoded, not encrypted, so HTTPS is needed to protect them during transmission.

Which HTTP header contains the Basic Authentication credentials?

A Content-Type

B User-Agent

C Authorization

D Accept

The Authorization header carries the Basic Authentication credentials.

What is the format of the Authorization header for Basic Authentication?

A Basic <Base64 encoded username:password>

B Digest <hash>

C Bearer <token>

D Token <API key>

Basic Authentication uses 'Basic' followed by the Base64 encoded username and password.

Explain how Basic Authentication works in API testing using Postman.

Think about how credentials are sent and where you enter them in Postman.

Why is it important to use HTTPS when using Basic Authentication?

Consider the security risks of sending encoded but not encrypted data.

Practice

1. What does Basic Authentication in Postman primarily require to access a protected API?

easy

A. A username and password

B. An API key only

C. A token generated by OAuth

D. No credentials, just the URL

Solution

1. Step 1: Understand Basic Authentication

   Basic Authentication requires a username and password to verify identity.

2. Step 2: Identify Postman's method

   Postman uses these credentials to add an Authorization header automatically.

3. Final Answer:

   A username and password -> Option A

4. Quick Check:

   Basic Auth = username + password [OK]

Hint: Basic Auth always needs username and password [OK]

Common Mistakes:

• Confusing Basic Auth with API key or OAuth tokens
• Thinking no credentials are needed
• Using only username or only password

2. Which is the correct way to set Basic Authentication in Postman?

easy

A. Select 'Basic Auth' in the Authorization tab and enter credentials

B. Use the Body tab to send username and password

C. Put credentials in the URL query parameters

D. Add username and password in the Headers tab manually

Solution

1. Step 1: Locate Authorization tab in Postman

   Postman provides an Authorization tab to set authentication types easily.

2. Step 2: Choose Basic Auth and enter credentials

   Selecting Basic Auth lets you enter username and password which Postman encodes automatically.

3. Final Answer:

   Select 'Basic Auth' in the Authorization tab and enter credentials -> Option A

4. Quick Check:

   Use Authorization tab for Basic Auth [OK]

Hint: Use Authorization tab, not Headers or Body [OK]

Common Mistakes:

• Manually adding Authorization header incorrectly
• Putting credentials in URL which is insecure
• Sending credentials in request body for Basic Auth

3. What will Postman send in the Authorization header when you enter username 'user1' and password 'pass123' for Basic Auth?

medium

A. Authorization: Basic user1:pass123

B. Authorization: Bearer user1:pass123

C. Authorization: Basic dXNlcjE6cGFzczEyMw==

D. Authorization: Token dXNlcjE6cGFzczEyMw==

Solution

1. Step 1: Understand Basic Auth header format

   Basic Auth sends 'Authorization: Basic ' plus base64 encoding of 'username:password'.

2. Step 2: Encode 'user1:pass123' in base64

   Encoding 'user1:pass123' results in 'dXNlcjE6cGFzczEyMw=='.

3. Final Answer:

   Authorization: Basic dXNlcjE6cGFzczEyMw== -> Option C

4. Quick Check:

   Basic Auth header = 'Basic ' + base64(username:password) [OK]

Hint: Basic Auth header is 'Basic ' + base64(username:password) [OK]

Common Mistakes:

• Using 'Bearer' instead of 'Basic'
• Sending plain username:password without encoding
• Confusing token or API key formats

4. You set Basic Auth in Postman but get a 401 Unauthorized error. What is the most likely cause?

medium

A. Using HTTPS instead of HTTP

B. Incorrect username or password entered

C. Headers tab is empty

D. Request body is missing

Solution

1. Step 1: Understand 401 Unauthorized meaning

   401 means the server rejected the credentials provided.

2. Step 2: Check credentials correctness

   Most common cause is wrong username or password causing authentication failure.

3. Final Answer:

   Incorrect username or password entered -> Option B

4. Quick Check:

   401 error = bad credentials [OK]

Hint: 401 usually means wrong username or password [OK]

Common Mistakes:

• Thinking HTTPS causes 401 error
• Assuming missing body causes authentication failure
• Ignoring credential typos

5. You want to test an API with Basic Auth but keep your password secure. Which Postman feature helps you avoid exposing your password in the request headers?

hard

A. Write the password directly in the URL

B. Disable SSL verification

C. Send credentials in the request body as plain text

D. Use environment variables to store credentials and reference them

Solution

1. Step 1: Identify secure ways to handle credentials

   Storing credentials in environment variables keeps them hidden and reusable.

2. Step 2: Use variables in Authorization tab

   Referencing variables in Basic Auth fields avoids hardcoding sensitive info in requests.

3. Final Answer:

   Use environment variables to store credentials and reference them -> Option D

4. Quick Check:

   Environment variables protect sensitive data [OK]

Hint: Use environment variables for credentials security [OK]

Common Mistakes:

• Putting password in URL exposes it
• Sending password in body is insecure for Basic Auth
• Disabling SSL reduces security, not protects password