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Hyunjung
Hyunjung

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How to start FastAPI?

#api #beginners #tutorial #python

I’m starting a new FastAPI project for my capstone, and I want to document the entire process so I can look back on it later.

Prerequisites

  • Python 3.10+ installed
  • Git installed and configured
  • A GitHub account
  • Basic terminal knowledge

1. Create your project folder 

mkdir my-project
cd my-project
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2. Set up a virtual environment

Always use a virtual environment.

python -m venv venv
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Activate it:

# macOS / Linux
source venv/bin/activate

# Windows (CMD)
venv\Scripts\activate.bat
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Your terminal prompt should now show (venv) at the start.

3. Install FastAPI and Uvicorn 

pip install fastapi uvicorn
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uvicorn is the ASGI server that runs your FastAPI app.

4. Freeze your dependencies 

pip freeze > requirements.txt
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This creates a requirements.txt file so anyone can reproduce your environment with:

pip install -r requirements.txt
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5. Create your first app

Create a file called main.py at the root of your project:

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"message": "Hello, FastAPI!"}
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6. Run the dev server 

uvicorn main:app --reload
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Now open your browser and visit:

  • http://127.0.0.1:8000 — your root endpoint
  • http://127.0.0.1:8000/docs — auto-generated Swagger UI

FastAPI auto-generates interactive API docs from your code.

7. Structure your project (optional but recommended)

For a capstone or real project, a flat main.py will get messy fast. Here's a minimal structure that scales well:

my-fastapi-project/
├── app/
│   ├── __init__.py
│   ├── main.py
│   └── models/
│       ├── __init__.py
├── requirements.txt
├── .gitignore
└── README.md
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Update your entry point to point to app.main:

uvicorn app.main:app --reload
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8. Add a .gitignore

Before committing anything, create a .gitignore so you don't accidentally push your virtual environment or secrets:
you can get text from gitignore.io

9. Write a README.md

just as you want~

10. Initialize Git and push to GitHub

  • Create a repo on GitHub
  • Connect and push

This is really easy and you can do it.

Done! Your FastAPI project is now on GitHub.

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