Poetry has become one of the easiest and cleanest ways to manage Python dependencies, virtual environments, and reproducible builds. If you’re building APIs with FastAPI, using Poetry keeps your project organized and makes setup consistent across machines—especially when you’re working in VS Code.

In this guide, you’ll install Poetry on Windows (PowerShell/CMD), create a FastAPI project using pyproject.toml, set up a local .venv for VS Code, install dependencies, and run your API using Uvicorn. Everything is written to match your project path:
C:\Users\Azhar Computer\python-fast-api

|| Also read Also read Build a Data-Science–Powered SaaS That Scales in 2026

What you’ll build

• Poetry installed and working on Windows
• A FastAPI app inside app/main.py
• Dependencies managed via pyproject.toml + poetry.lock
• A local virtual environment .venv that VS Code can detect
• A running development server with auto-reload

Prerequisites

• Python 3.9+ installed on Windows
• VS Code installed + Python extension
• Your folder already exists:
  C:\Users\Azhar Computer\python-fast-api
• You already created pyproject.toml using poetry init

Step-by-step commands (and where to run them)

Step 1 — Install Poetry (one-time)

Where to run: PowerShell (recommended) OR VS Code Terminal (PowerShell)

(Invoke-WebRequest -Uri https://install.python-poetry.org -UseBasicParsing).Content | py -

Close and reopen terminal, then verify:

poetry --version

If poetry is not recognized, you likely need to add Poetry to PATH. Add:
%APPDATA%\Python\Scripts to User PATH, then reopen terminal.

Step 2 — Open your project in VS Code

Where to do this: VS Code (GUI)

1. Open VS Code
2. File → Open Folder
3. Select:
   C:\Users\Azhar Computer\python-fast-api

Step 3 — Go to your project folder in terminal

Where to run: VS Code Terminal (PowerShell) (best)

cd "C:\Users\Azhar Computer\python-fast-api"
dir

You should see pyproject.toml.

Step 4 — Make Poetry create .venv inside the project (recommended for VS Code)

Where to run: VS Code Terminal (PowerShell)

poetry config virtualenvs.in-project true --local

This helps VS Code automatically detect the correct interpreter at:
.venv\Scripts\python.exe

Step 5 — Add FastAPI and Uvicorn

Where to run: VS Code Terminal (PowerShell)

poetry add fastapi "uvicorn[standard]"

This updates:

• pyproject.toml
• poetry.lock

Step 6 — Install dependencies from poetry.lock

Where to run: VS Code Terminal (PowerShell)

Option A (recommended for many FastAPI apps): install dependencies only

poetry install --no-root

Option B: install dependencies + install your project package

poetry install

Which one should you use?

• Use --no-root if your project is just an app and you don’t need to install it as a package.
• Use normal poetry install if you want your project installed into the environment as a package.

Step 7 — Create your FastAPI app file

Where to do: VS Code (Explorer + Editor)

Create this structure:

python-fast-api/
  pyproject.toml
  app/
    main.py

Put this code in app/main.py:

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def root():
    return {"ok": True}

Important: Don’t name any file fastapi.py (it will clash with the FastAPI package import).

Step 8 — Run the development server

Where to run: VS Code Terminal (PowerShell)

poetry run uvicorn app.main:app --reload

Now open:

• App: http://127.0.0.1:8000
• Docs: http://127.0.0.1:8000/docs

Stop server:

• Press Ctrl + C in the terminal

|| Also read Advanced AI and Data Science Roadmap for Job-Ready Professionals (2026 Guide)

Step 9 — Select the correct Python interpreter in VS Code

Where to do: VS Code (GUI)

1. Press Ctrl + Shift + P
2. Choose Python: Select Interpreter
3. Select:
   C:\Users\Azhar Computer\python-fast-api\.venv\Scripts\python.exe

Now VS Code will:

• resolve imports correctly
• run/debug using the same environment
• show correct linting and IntelliSense

Conclusion

With Poetry installed on Windows and your .venv created inside the project, you now have a clean, repeatable FastAPI setup that works smoothly in VS Code. From here, you can add MongoDB support, environment variables, routers, and production deployment tools while keeping your dependencies locked and predictable via poetry.lock.

FAQs

1) What’s the difference between poetry install and poetry install --no-root?

• poetry install installs dependencies and installs your project as a package.
• poetry install --no-root installs only dependencies (common for app-style FastAPI projects).

2) Why should I use .venv inside the project?

It makes VS Code interpreter detection easier and keeps your environment contained per project. No confusion with global virtualenvs.

3) I got an error: “project.name must match pattern…”

Your pyproject.toml name likely has spaces or invalid characters. Use a valid name like:
python-fast-api, python_fast_api, my-api.

4) Where should I run these commands: CMD or PowerShell?

You can use either, but the smoothest workflow is:

• VS Code Terminal (PowerShell) for most commands
• PowerShell for installing Poetry (official installer command)

5) How do I check which packages are installed?

Run:

poetry show