Understanding HTTP Methods and Status

🔍 What Are HTTP Methods?

When building or using web APIs, understanding HTTP methods and the status codes that come with them is essential. Whether you’re writing a backend service or integrating with one, these two concepts go hand-in-hand — the method describes what the client wants to do, and the status code describes what actually happened.

HTTP methods are verbs that describe the kind of operation the client wants the server to perform on a resource. For example:

• Want to read something? Use GET.
• Want to create something? Use POST.
• Want to update something fully? Use PUT.
• Want to update something partially? Use PATCH.
• Want to delete something? Use DELETE.

When used correctly, they make APIs easier to understand, maintain, and use consistently across teams.

Each method also pairs with different HTTP status codes, which are short responses from the server telling you what happened. For example:

• 200 OK means the request was successful
• 404 Not Found means the resource doesn’t exist
• 201 Created means a new resource was successfully added

Let’s walk through each method and its most common status codes.

🟢 GET — Fetch Data

GET is used to retrieve data from the server. It does not modify anything — just fetches.

Example:

GET /users/123

• This asks the server to return the user with ID 123.

Common Status Codes:

Code	Meaning
200 OK	Resource found and returned successfully
304 Not Modified	Resource hasn’t changed (used with caching)
404 Not Found	Resource does not exist
401 Unauthorized	User is not authenticated
403 Forbidden	User doesn’t have access

🟡 POST — Create a Resource

POST is used to create a new resource on the server. It usually goes with a JSON body in the request.

Example:

POST /users
Content-Type: application/json

{
  "name": "Alice",
  "email": "alice@example.com"
}

• This tells the server to create a new user with the given data.

Common Status Codes:

Code	Meaning
201 Created	New resource was successfully created
400 Bad Request	Malformed input or missing required fields
409 Conflict	Duplicate or conflicting data (e.g. email already exists)
422 Unprocessable Entity	Validation failed (common in RESTful APIs)

🔵 PUT — Replace a Resource

PUT is used to completely replace a resource. Think of it as "update the whole thing."

Example:

PUT /users/123
Content-Type: application/json

{
  "name": "Alice Smith",
  "email": "alice.smith@example.com"
}

• This replaces the existing user 123 with the new data.

Common Status Codes:

Code	Meaning
200 OK	Resource replaced, and response includes the updated object
204 No Content	Resource replaced successfully, no response body
400 Bad Request	Invalid input
404 Not Found	Resource doesn’t exist to be updated

🟣 PATCH — Update a Resource Partially

PATCH is used to partially update a resource — unlike PUT, which replaces the whole thing.

Example:

PATCH /users/123
Content-Type: application/json

{
  "name": "Alice S."
}

• This only updates the name field for user 123.

Common Status Codes:

Code	Meaning
200 OK	Partial update succeeded, response includes updated resource
204 No Content	Update succeeded, no body returned
400 Bad Request	Invalid or incomplete input
404 Not Found	Target resource not found

🔴 DELETE — Remove a Resource

DELETE is used to delete a resource permanently from the server.

Example:

DELETE /users/123

• This deletes the user with ID 123.

Common Status Codes:

Code	Meaning
204 No Content	Successfully deleted, nothing more to say
200 OK	Successfully deleted, with a message or response body
404 Not Found	Resource wasn’t found to delete
403 Forbidden	User is not allowed to delete this resource

🎯 Final Thoughts

You don’t need to memorize every HTTP status code — just understand the typical ones that go with each method. Think of methods as intents and status codes as results. When you design APIs with this mindset, your endpoints become much easier to work with, test, and document.

Thank you

Big thanks for reading! You’re awesome, and I hope this post helped. Until next time!