What Are APIs? A Beginner’s Guide for Aspiring Devs

Hey everyone! 👋 I'm Palesa 2lo, a software engineer and tech lead. If you're just starting out in tech or curious about how apps talk to each other, you're in the right place. Today, let’s break down APIs—what they are, why they matter, and how you can test them using Postman.

🧠 What is an API?

API **stands for Application Programming Interface.** Think of it as a waiter in a restaurant—you (the client) make a request, and the API delivers your request to the kitchen (server), then returns the result back to you be it your food or a problem like wrong order(response).
It lets different software systems communicate. For example:
• Checking the weather.
• Instagram uses APIs to post images, fetch user data, and show comments.

🧱 Key Components of an API Request

**
When you interact with an API, these are the parts to pay attention to:

🔗 1. URL (Endpoint)

This is where your request is sent. It usually looks like:

https://api.example.com/users

https://api.example.com/usersUpdate?userid=122

🛠 2. Method Type

Defines the action:
• GET → Retrieve data
• POST → Send new data
• PUT → Update data
• DELETE → Remove data

🧾 3. Headers

These carry metadata. Common ones include:
• Content-Type: application/json
• Authorization: Bearer <>, basic auth, API Key etc

📦 4. Data Format

There are few types of data format in API's, Like query params which will be on the querystring. Example:
Query params

https://api.example.com/usersUpdate?userid=122&name=palesa

Then JSON which I believe is the most common one. Example:

Raw :Json

{
 "name": "Palesa",
 "email": "pp.thulo@gmail.com"
}

Form-url-encoded

var formData = new Dictionary<string, string>
{
    { "username", "palesa" },
    { "password", "passwordIsASecret@6" }
};

There could be more like XML, and many more.

🔐 API Authentication

Most APIs need a key or token to verify who you are. You might get this from platforms like RapidAPI when signing up.

🧪 Testing with Postman

We used Postman to test an API. Here’s what we did:
1 Created a new request
2 Selected GET or POST method
3 Added the endpoint URL
4 Set headers and body (if needed)
5 Clicked Send
6 Saw the response 🎉

Postman is a great way to learn what happens behind the scenes in real-time.

✅ Wrap-Up

So now you know:
• What APIs are
• What parts make up an API request
• How to test an API using Postman
This is just the beginning—APIs are everywhere. And trust me, once you get this, a whole new world opens up.
👩🏽‍💻 Follow me here and on YouTube at Beyond Tech with Mbalz for more beginner-friendly tech content!