What is REST API?

REST API Explained

REST (Representational State Transfer) is the most widely used architectural style for web APIs. Created by Roy Fielding in 2000, REST uses standard HTTP methods to perform CRUD operations on resources. Each resource has a unique URL, and the API is stateless—meaning each request contains all the information needed to process it. RESTful APIs are the industry standard for web and mobile development because they're simple, scalable, and universally understood. At M3L Software, we build REST APIs with FastAPI that follow best practices: proper HTTP status codes, pagination, filtering, HATEOAS links, and comprehensive OpenAPI documentation.

Key Features

Common Use Cases

Code Example

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel

app = FastAPI()

class UserCreate(BaseModel):
    name: str
    email: str

users_db = {}

@app.get("/users")
async def list_users(skip: int = 0, limit: int = 10):
    items = list(users_db.values())[skip:skip + limit]
    return {"users": items, "total": len(users_db)}

@app.get("/users/{user_id}")
async def get_user(user_id: int):
    if user_id not in users_db:
        raise HTTPException(status_code=404, detail="User not found")
    return users_db[user_id]

@app.post("/users", status_code=201)
async def create_user(user: UserCreate):
    user_id = len(users_db) + 1
    users_db[user_id] = {"id": user_id, **user.dict()}
    return users_db[user_id]

A RESTful API built with FastAPI demonstrating proper HTTP methods, status codes, pagination, error handling with HTTPException, and Pydantic models for input validation.

Frequently Asked Questions

Related Terms