API Terminologies Explained – HTTP, HTTPS, Methods, and Endpoints

🌐 1️⃣ HTTP & HTTPS

🔸 What is HTTP?

HTTP (HyperText Transfer Protocol) is the foundation of communication on the web.
It defines how data is requested and delivered between a client (like Postman or browser) and a server.

When you type a URL or send an API request:

• The client sends an HTTP request.

• The server processes it and returns a response (data, status code, headers).

🧩 Example:

Request →  GET https://jsonplaceholder.typicode.com/posts/1
Response → 200 OK

🔸 What is HTTPS?

HTTPS (HTTP Secure) is the secure version of HTTP, where communication between client and server is encrypted using SSL/TLS.
This ensures:

• 🔒 Data privacy (cannot be intercepted easily)

• ✅ Authentication (verifies server identity)

• 🛡️ Integrity (data not altered in transit)

💡 In short:
HTTP = plain communication
HTTPS = secure & encrypted communication

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📦 2️⃣ Resource & Payload

🔹 Resource

In an API, everything is treated as a resource — users, posts, products, or orders.
Each resource is identified by a unique URL (endpoint).

🧠 Example:

• /users → represents a collection of users

• /users/5 → represents a single user with ID = 5

So when you make a request:

GET https://dummyjson.com/users/5

You’re requesting the resource “User 5.”

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🔹 Payload

The payload is the data sent to the server in the body of an HTTP request — usually with POST or PUT methods.

🧾 Example (POST request payload):

{
  "name": "Hitendra",
  "email": "hitendra@test.com",
  "role": "admin"
}

Here, this JSON object is the payload that the API receives and processes.

Tip:

• GET requests don’t usually have payloads.

• POST/PUT requests do.

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🧮 3️⃣ HTTP Methods

HTTP methods define what action you want to perform on a resource.
Here are the most common methods used in API testing 👇

Method	Description	Example
GET	Retrieve data from a server	GET /users
POST	Send new data to the server (create resource)	POST /users
PUT	Update an existing resource	PUT /users/3
PATCH	Partially update a resource	PATCH /users/3
DELETE	Remove a resource	DELETE /users/3
HEAD	Same as GET but without body (for metadata)	HEAD /users

💬 Real-life analogy:

Action	Example	HTTP Method
View list of customers	“Show me all users”	GET
Add new customer	“Register a new user”	POST
Update user details	“Change email of user 3”	PUT/PATCH
Remove user	“Delete user 3”	DELETE

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Sample HTTP post request:

🔗 4️⃣ URI, URL, URN, and Endpoint

These four terms often confuse beginners, so let’s simplify them 👇

🧱 URI (Uniform Resource Identifier)

A URI is a general term for identifying a resource — it can be a name, location, or both.
It’s the umbrella term that covers both URL and URN.

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🌍 URL (Uniform Resource Locator)

A URL tells you where a resource is located on the web.
It includes the protocol, domain, and path.

🧾 Example:

https://api.github.com/users/hitendra

Here:

• https → Protocol

• api.github.com → Domain

• /users/hitendra → Path to the resource

So this URL locates the user resource named “hitendra” in GitHub’s API.

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🧾 URN (Uniform Resource Name)

A URN identifies a resource by name, not by its location.
It doesn’t include protocol or domain.

Example:

urn:isbn:9780141033570

This refers to a book by its ISBN number — not where it is stored.

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📍 Endpoint

An Endpoint is the specific URL where an API resource can be accessed.
It’s the address you hit when making API calls.

Example:

Base URL: https://dummyjson.com
Endpoint: /products/10
Full URL: https://dummyjson.com/products/10

📊 Visual Summary Diagram

[Client] → [HTTP/HTTPS Request] → [Server]
        ↘ Resource (e.g., /users/5)
          ↘ Payload (if POST/PUT)
          ↘ Endpoint = Base URL + Resource Path

URI, URL, URN, Endpoint

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🧠 Quick Recap

✅ HTTP – defines communication protocol
✅ HTTPS – secure version of HTTP
✅ Resource – entity (user, post, etc.)
✅ Payload – data sent to server
✅ HTTP Methods – actions on resources
✅ URI = identifier
✅ URL = locator
✅ URN = name
✅ Endpoint = actual callable address