200 OK and 201 Created in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the HTTP status code 200 OK mean?

It means the request was successful, and the server has returned the requested data or completed the action.

beginner

When should a server respond with 201 Created?

When a new resource has been successfully created as a result of the client's request, the server responds with 201 Created.

intermediate

What is a common difference between 200 OK and 201 Created responses?

200 OK means the request succeeded generally, while 201 Created specifically means a new resource was made.

intermediate

In REST APIs, what should the server include in the response when sending 201 Created?

The server should include a Location header with the URL of the newly created resource.

beginner

True or False: A 200 OK response can be used for both GET and POST requests.

True. 200 OK is a general success status and can be used for many request types, including GET and POST.

Which HTTP status code indicates a resource was successfully created?

A 201 Created

B 200 OK

C 404 Not Found

D 500 Internal Server Error

201 Created means the server successfully created a new resource.

What does a 200 OK status code usually mean?

A Server error

B Resource created

C Client error

D Request succeeded

200 OK means the request was successful.

When responding with 201 Created, what should the server include?

A Empty body

B Location header with new resource URL

C Error message

D Redirect URL

The Location header tells the client where to find the new resource.

Can 200 OK be used for a successful POST request?

A Yes

B No

C Only for GET requests

D Only for DELETE requests

200 OK can be used for any successful request, including POST.

Which status code is NOT appropriate for a successful resource creation?

A 201 Created

B 200 OK

C 404 Not Found

D None of the above

404 Not Found means the resource was not found, so it is not appropriate for creation success.

Explain the difference between 200 OK and 201 Created in REST APIs.

Think about when you create something new versus just getting data.

Describe when and why a server should use the 201 Created status code.

Focus on resource creation and client notification.

Practice

1. What does the HTTP status code 200 OK indicate in a REST API response?

easy

A. A new resource was successfully created on the server.

B. The request was successful and the server is returning the requested data or confirmation.

C. The client made a bad request and the server could not understand it.

D. The server encountered an error and could not complete the request.

Solution

1. Step 1: Understand the meaning of 200 OK

   The status code 200 OK means the request was successful and the server is sending back the requested data or confirmation.

2. Step 2: Compare with other codes

   201 Created means a new resource was created, which is different from 200 OK.

3. Final Answer:

   The request was successful and the server is returning the requested data or confirmation. -> Option B

4. Quick Check:

   200 OK = Success with data [OK]

Hint: 200 OK means success with data returned [OK]

Common Mistakes:

• Confusing 200 OK with 201 Created
• Thinking 200 means resource creation
• Mixing 200 with client or server error codes

2. Which of the following is the correct way to indicate a successful creation of a new resource in a REST API response?

easy

A. HTTP/1.1 201 Created

B. HTTP/1.1 404 Not Found

C. HTTP/1.1 500 Internal Server Error

D. HTTP/1.1 200 OK

Solution

1. Step 1: Identify the status code for resource creation

   The status code 201 Created is used when a new resource is successfully created on the server.

2. Step 2: Eliminate incorrect options

   200 OK means success but not necessarily creation; 404 and 500 are error codes.

3. Final Answer:

   HTTP/1.1 201 Created -> Option A

4. Quick Check:

   201 Created = New resource created [OK]

Hint: Use 201 Created for new resource success [OK]

Common Mistakes:

• Using 200 OK instead of 201 for creation
• Confusing 404 Not Found as success
• Mixing error codes with success codes

3. Consider this REST API response code snippet:

HTTP/1.1 201 Created
Location: /users/123

{"id":123,"name":"Alice"}

What does this response tell the client?

medium

A. The client made a bad request and should try again.

B. The request failed and no resource was created.

C. The server is returning existing user data without creating anything new.

D. A new user resource was created with ID 123, and its location is provided.

Solution

1. Step 1: Analyze the status code 201 Created

   This code means a new resource was successfully created on the server.

2. Step 2: Interpret the Location header and response body

   The Location header shows where the new resource is located (/users/123), and the body contains the new user's data.

3. Final Answer:

   A new user resource was created with ID 123, and its location is provided. -> Option D

4. Quick Check:

   201 Created + Location header = New resource created [OK]

Hint: 201 with Location means new resource created [OK]

Common Mistakes:

• Ignoring the Location header
• Thinking 201 means failure
• Confusing 201 with 200 OK

4. You wrote a REST API endpoint to create a new product. The server returns 200 OK instead of 201 Created. What is the likely issue?

medium

A. The server did not create a new resource but only confirmed the request.

B. The client sent an invalid request format.

C. The server successfully created the resource but forgot to set the correct status code.

D. The server encountered an internal error while creating the resource.

Solution

1. Step 1: Understand the difference between 200 OK and 201 Created

   200 OK means success but not necessarily resource creation; 201 Created explicitly means a new resource was created.

2. Step 2: Analyze the server behavior

   If the resource was created but 200 OK was returned, the server likely forgot to set the correct status code.

3. Final Answer:

   The server successfully created the resource but forgot to set the correct status code. -> Option C

4. Quick Check:

   201 Created must be set on resource creation [OK]

Hint: 201 must be set when resource is created [OK]

Common Mistakes:

• Assuming 200 OK means creation
• Ignoring status code importance
• Confusing client errors with server response codes

5. You are designing a REST API for a blog. When a new post is created, you want to return the correct status code and the URL of the new post. Which response is the best practice?

hard

A. Return 201 Created with the Location header set to the new post URL and the post data in the body.

B. Return 404 Not Found because the post did not exist before.

C. Return 200 OK with the post data in the body but no Location header.

D. Return 500 Internal Server Error to indicate the server created the post.

Solution

1. Step 1: Identify the correct status code for resource creation

   201 Created is the standard code to indicate a new resource was successfully created.

2. Step 2: Use the Location header to provide the new resource URL

   Including the Location header with the new post URL helps clients find the resource easily.

3. Final Answer:

   Return 201 Created with the Location header set to the new post URL and the post data in the body. -> Option A

4. Quick Check:

   201 Created + Location header = Best practice for new resource [OK]

Hint: Use 201 Created + Location header for new resources [OK]

Common Mistakes:

• Returning 200 OK without Location header
• Using error codes for successful creation
• Not including the new resource URL