Your First API Endpoint
Learn to create simple GET endpoints, define routes, and return basic JSON responses.
Your First API Endpoint is a free FastAPI Backend Development Bootcamp lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the FastAPI Backend Development Bootcamp learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What's an API Endpoint?
An API endpoint is a specific URL your API exposes — an address that receives requests and returns a service. We start with GET, used to fetch data.
Your FastAPI Application
Every app starts from a FastAPI instance, conventionally named app. This object is the core where all your routes and logic live.
from fastapi import FastAPI
app = FastAPI()
# This 'app' object is where your API lives!Defining Routes with Decorators
FastAPI uses decorators to bind a URL path to a function. @app.get("/") says: on a GET to the root path, run the function below.
Your First 'Hello World' Endpoint
Here is the classic API Hello World — a single GET endpoint at /. Run it and hit the root in your browser or Postman.
from fastapi import FastAPI
app = FastAPI()
@app.get("/")
def read_root():
return {"message": "Hello, CoddyKit!"}
# To run: Save as main.py, then 'uvicorn main:app --reload'Running Your FastAPI App
Run your app with Uvicorn: uvicorn main:app --reload finds app in main.py and auto-restarts whenever you edit code.
FastAPI's JSON Magic
FastAPI's JSON magic: return a Python dict or list and it serializes to a JSON response automatically — no manual conversion needed.
Returning Structured JSON Data
Return a richer Python dict and FastAPI ships it as structured JSON. Here, an endpoint hands back full product details.
from fastapi import FastAPI
app = FastAPI()
@app.get("/product")
def get_product_info():
return {
"id": "CK001",
"name": "CoddyKit Pro Course",
"price": 49.99,
"available": True
}
# Run with: uvicorn main:app --reload
# Access this endpoint at /productCreating Multiple Endpoints
An API has many endpoints, each for a different resource. Define as many as you need on one app — here, two distinct GET routes.
from fastapi import FastAPI
app = FastAPI()
@app.get("/")
def read_root():
return {"message": "Welcome to our API!"}
@app.get("/items")
def get_items():
return [
{"id": 1, "name": "Laptop"},
{"id": 2, "name": "Mouse"},
{"id": 3, "name": "Keyboard"}
]
# Run with: uvicorn main:app --reload
# Access at / and /itemsEndpoint Naming Conventions
Good endpoint naming keeps an API readable: plural nouns for collections, short lowercase hyphenated paths, and no verbs — the HTTP method implies the action.
Quick Check
Which of the following code snippets correctly defines a FastAPI GET endpoint at the path /status that returns a JSON object {"status": "OK"}?
Lesson Summary
Solid! You built endpoints with decorators, returned dicts as JSON, and ran the app via Uvicorn. Next: making routes dynamic with URL data.
Frequently asked questions
Is the “Your First API Endpoint” lesson free?
Yes — the full text of “Your First API Endpoint” is free to read here on the web, and the FastAPI Backend Development Bootcamp course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the FastAPI Backend Development Bootcamp course, upgrade to CoddyKit PRO.
What will I learn in “Your First API Endpoint”?
Learn to create simple GET endpoints, define routes, and return basic JSON responses. You practise FastAPI Backend Development Bootcamp with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start FastAPI Backend Development Bootcamp?
No prior experience is required. FastAPI Backend Development Bootcamp on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Your First API Endpoint” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this FastAPI Backend Development Bootcamp lesson?
Yes. Every FastAPI Backend Development Bootcamp lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Introduction to FastAPI & Setup
- Your First API Endpoint
- Path & Query Parameters
- Interactive API Docs with Swagger UI