Step by Step FastAPI Setup

This guide shows the step-by-step setup of FastAPI on Windows OS and VS Code IDE.

• Navigate to Download Python, download and install Python with admin privileges and add python.exe to the PATH.

• Verify that Python is successfully installed by running the Python command in CMD:

• Verify that PIP (Python package installer) is installed by running the command in CMD:

• Create a project directory folder(ex. fastapi-setup in a folder named Code on drive D).

  D:\cd Code
  D:\Code> mkdir fastapi-setup
  

• From now on, let’s use VS Code to perform other FastAPI setup steps. Open a previously created folder in VS Code and run terminal from Terminal > New Terminal. We need to create a virtual environment inside our project by running the following command:

  python -m venv .venv
  

  If Python not found message appears, restart your PC to update Python installation PATH variables.

python -m venv .venv command creates a new virtual environment in a directory called .venv.

• Activate the Virtual Environment

  .venv\Scripts\Activate.ps1
  

If previous command doesn’t activate the virtual environment and there is an error message: Activate.ps1 : The term ‘Activate.ps1’ is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. If you trust this command, instead type: “.\activate”. See “get-help about_Command_Precedence” for more details. then:

• Step 1: run the command:

  Set-ExecutionPolicy RemoteSigned -Scope CurrentUser
  

• Step 2: run the command to activate virtual environment

  # run inside Scripts directory
  .\activate
  

• Check the Virtual Environment is active

  Get-Command python
  

  If it shows the python binary at .venv\Scripts\python, inside of your project (in this case fastapi-setup), then it worked.

• Run the following command to install FastAPI

  #  Make sure you put "fastapi[standard]" in quotes to ensure it works in all terminals.
  pip install "fastapi[standard]"
  

• Create main.py inside project and add following code to test and run FastAPI server

from typing import Union
from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
        return {"Hello from":"FastAPI"}

• Run FastAPI server with:

fastapi dev main.py

• Go to 127.0.0.1:8000. If setup was done properly than response should be displayed similar to image below.

• Deactivate virtual environment

  # In .venv folder
  .\deactivate
  

Key Takeaways

• Create a project and open folder in VS Code.
• Create a virtual environment:

  uv venv
  

• Activate virtual environment and do this every time you start a new terminal session to work on the project.

  .venv\Scripts\Activate.ps1
  

• Every time you install a new package in that environment, activate the environment again.

• Check the Virtual Environment is Active

  Get-Command python
  

  If it shows the python binary at .venv\Scripts\python, inside of created project, then it worked.

• Install packages - after activating the environment, you can install packages in it.

  uv pip install "fastapi[standard]"
  

• Create main.py and write some code.

• Run the FastAPI server.

  fastapi dev main.py
  

• Deactivate the virtual environment.

  deactivate
  

• Activate virtual environment again when starting working on a project.