Basic authentication in Postman

Introduction

Basic authentication helps check who you are before letting you use a service. It keeps things safe by asking for a username and password.

When testing an API that needs a username and password to access data.

When you want to make sure only allowed users can get information from a server.

When you are learning how to secure web services with simple login checks.

When you want to quickly test if login details work without complex setups.

Syntax

Postman

In Postman, select the Authorization tab.
Choose 'Basic Auth' from the Type dropdown.
Enter your Username and Password.
Postman will add the Authorization header automatically.

Basic Auth sends your username and password encoded in base64.

Always use HTTPS to keep your credentials safe when using Basic Auth.

Examples

This sets the username to 'user123' and password to 'pass123' for the request.

Postman

Type: Basic Auth
Username: user123
Password: pass123

Use this to test admin access with username 'admin' and password 'secret'.

Postman

Type: Basic Auth
Username: admin
Password: secret

Sample Program

This is a GET request to an API with Basic Auth header. The string after 'Basic' is the base64 encoding of 'user123:pass123'.

Postman

GET https://api.example.com/data
Authorization: Basic dXNlcjEyMzpwYXNzMTIz

Important Notes

Basic Auth is simple but not very secure alone; always use it with HTTPS.

Postman helps by encoding credentials automatically, so you don't have to do it yourself.

Summary

Basic authentication uses username and password to protect access.

Postman makes it easy to add Basic Auth to your API requests.

Always test with secure connections to keep your info safe.

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