200 OK and 201 Created in Rest API - Step-by-Step Execution

Concept Flow - 200 OK and 201 Created

Client sends HTTP request

↓

Server processes request

↓

Check if resource created?

Yes→Respond with 201 Created

No↓

Respond with 200 OK

↓

Client receives response

The server checks if a new resource was created. If yes, it sends 201 Created; otherwise, it sends 200 OK.

Execution Sample

Rest API

POST /items HTTP/1.1
Host: example.com
Content-Type: application/json

{
  "name": "New Item"
}

Client sends a POST request to create a new item on the server.

Execution Table

Step	Action	Condition	Response Code	Response Meaning
1	Client sends POST request to /items	N/A	N/A	N/A
2	Server receives request	N/A	N/A	N/A
3	Server checks if new item created	Item created successfully	201	Created - new resource made
4	Server sends response	N/A	201	Client knows item was created
5	Client receives response	N/A	201	Client confirms creation
6	Client sends GET request to /items/123	N/A	N/A	N/A
7	Server processes GET request	Resource exists	200	OK - resource found
8	Server sends response	N/A	200	Client receives resource data
9	Client receives response	N/A	200	Client confirms success

💡 Execution stops after client receives the server response.

Variable Tracker

Variable	Start	After Step 3	After Step 7	Final
Request Type	None	POST	GET	GET
Resource Created	False	True	True	True
Response Code	None	201	200	200

Key Moments - 3 Insights

Why does the server send 201 Created instead of 200 OK after a POST?

Because the server successfully created a new resource, it sends 201 Created to tell the client a new item was made (see execution_table row 3).

When does the server send 200 OK instead of 201 Created?

When the client requests existing data (like a GET), the server sends 200 OK to show the request succeeded without creating anything new (see execution_table row 7).

Can 201 Created be used for GET requests?

No, 201 Created is only for successful creation actions like POST. GET requests use 200 OK to indicate success (see execution_table rows 6-9).

Visual Quiz - 3 Questions

Look at the execution_table, what response code does the server send after successfully creating a new item?

A 404

B 200

C 201

D 500

💡 Hint

Check row 3 in the execution_table where the server confirms creation.

At which step does the server respond with 200 OK?

A Step 7

B Step 4

C Step 3

D Step 1

💡 Hint

Look at the response codes in the execution_table rows for GET requests.

If the server did not create a new resource after POST, which response code would it most likely send?

A 201 Created

B 200 OK

C 404 Not Found

D 400 Bad Request

💡 Hint

Refer to the concept_flow where no creation leads to 200 OK response.

Concept Snapshot

200 OK means the request succeeded and the server returned data.
201 Created means the request succeeded and a new resource was made.
Use 201 after POST creates something new.
Use 200 for successful GET or other requests without creation.
Clients use these codes to understand server actions.

Full Transcript

When a client sends a request to a server, the server processes it and decides what response code to send back. If the client asks to create something new, like with a POST request, and the server successfully creates it, the server sends back 201 Created. This tells the client a new resource was made. If the client asks for existing data, like with a GET request, the server sends 200 OK to show the request succeeded and data is returned. These codes help the client understand what happened on the server side.