What is API?

API Explained

An API (Application Programming Interface) defines how different software components should interact. Think of it as a waiter in a restaurant—you tell the waiter what you want (make a request), and the waiter brings back your food (returns a response) from the kitchen (the server). APIs are the backbone of modern software, enabling everything from mobile apps fetching weather data to payment processing systems like Stripe. At M3L Software, we build robust, well-documented APIs using FastAPI and Django that power SaaS platforms, mobile backends, and enterprise integrations. A well-designed API is scalable, secure, versioned, and thoroughly documented—making it easy for other developers to integrate with your system.

Key Features

Common Use Cases

Code Example

from fastapi import FastAPI

app = FastAPI()

@app.get("/api/users/{user_id}")
async def get_user(user_id: int):
    return {"id": user_id, "name": "John Doe", "email": "[email protected]"}

@app.post("/api/users")
async def create_user(name: str, email: str):
    return {"id": 1, "name": name, "email": email, "created": True}

A simple FastAPI application defining two API endpoints: one to retrieve a user by ID (GET) and another to create a new user (POST). FastAPI automatically generates interactive API documentation.

Frequently Asked Questions

Related Terms