API FUNDAMENTALS / LESSON 02

HTTP Methods.

GET, POST, PUT, DELETE explained

Written by Andrew Lee JenkinsPublished Oct 5, 202612 min readFree lesson

When you talk to an API, you've gotta tell it what you're trying to do. Grab some info? Save something new? Change something? Delete it? HTTP methods are how you say which one.

HTTP stands for Hypertext Transfer Protocol, and it's basically the language of the web. Any time you visit a website or use an app that connects to the internet, HTTP is working away in the background.

The Four Main Methods

There are four HTTP methods you'll use WAY more than any others. Each one tells the API what kind of action you want.

GET: Read Data

GET is the most common one. It means "give me some information." You're just looking around and nothing gets changed.

Examples of GET

Show me all the products
Show me user number 42
Show me today's weather

Example

GET /products
GET /users/42
GET /weather?city=Seattle

Every time you visit a website, your browser sends a GET request. It's basically saying "give me this webpage."

POST: Create Data

POST means "I'm sending you new data to save." You're creating something that didn't exist before.

Examples of POST

Create a new user account
Add a new product
Submit a new order

Example

POST /users
{
  "name": "Sarah",
  "email": "sarah@example.com"
}

Filled out a form on a website and clicked "Submit"? That was probably a POST request, sending your new info off to get saved.

PUT: Update Data

PUT means "replace this data with new data." You're changing something that already exists.

Examples of PUT

Update a user's email address
Change a product's price
Edit a blog post

Example

PUT /users/42
{
  "name": "Sarah",
  "email": "sarah.new@example.com"
}

PUT replaces the WHOLE thing. If you update a user, you send all their information, even the parts that didn't change.

DELETE: Remove Data

DELETE means "remove this." You're getting rid of something for good.

Examples of DELETE

Delete a user account
Remove a product from the store
Cancel an order

Example

DELETE /users/42

DELETE requests are usually simple. You just point at the thing you want gone. Be careful though... deleted data is often gone for good, and there's no "oops" button.

A Real-World Example

Say you're building a simple to-do list app. Here's how each method shows up.

Step 1. GET: View Your Tasks

When you open the app, it sends a GET request to grab all your tasks.

Example

GET /tasks

The server sends back your list of tasks.

Step 2. POST: Add a New Task

You type a new task and click "Add," and the app sends a POST request.

Example

POST /tasks
{
  "title": "Buy groceries",
  "completed": false
}

The server creates the task and saves it.

Step 3. PUT: Mark Task Complete

You check off a task, and the app sends a PUT request to update it.

Example

PUT /tasks/1
{
  "title": "Buy groceries",
  "completed": true
}

The server updates the task's status.

Step 4. DELETE: Remove a Task

You delete a task, and the app sends a DELETE request.

Example

DELETE /tasks/1

The server removes the task permanently.

CRUD Operations

You'll hear developers say CRUD a lot. It sounds gross, but it's just short for this.

Create = POST
Read = GET
Update = PUT
Delete = DELETE

Almost every app needs these four basic operations. Users, products, messages, whatever it is, you've gotta create them, read them, update them and delete them.

How Requests Travel

Here's what happens when you make an API request.

Your app builds a request with a method (GET, POST, etc.)
The request travels over the internet to the server
The server looks at the method to understand what you want
The server does the work (reads, creates, updates, or deletes)
The server sends a response back to your app

All of that happens in milliseconds. It feels instant, but there's a LOT going on behind the curtain.

Quick Reference

Method	Action	Example	Changes Data?
GET	Read	View a product	No
POST	Create	Add new product	Yes
PUT	Update	Change product price	Yes
DELETE	Remove	Delete a product	Yes

TL;DR

HTTP methods tell the API what action you want
GET = read data (doesn't change anything)
POST = create new data
PUT = update existing data
DELETE = remove data
CRUD (Create, Read, Update, Delete) is the foundation of most apps

What's Next?

Now you know the different ways to interact with an API. Next up are URLs and endpoints, the addresses where you actually send your requests...

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