ModuleNotFoundError: No module named 'fastapi' in Python

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Borislav Hadzhiev

Last updated: Apr 10, 2024
12 min

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# ModuleNotFoundError: No module named 'fastapi' in Python

The Python "ModuleNotFoundError: No module named 'fastapi'" occurs when we forget to install the fastapi module before importing it or install it in an incorrect environment.

To solve the error, install the module by running the pip install fastapi command.

modulenotfounderror no module named fastapi

Open your terminal in your project's root directory and install the fastapi module.

shell
# 👇️ In a virtual environment or using Python 2
pip install fastapi

# 👇️ For Python 3 (could also be pip3.10 depending on your version)
pip3 install fastapi

# 👇️ If you get a permissions error
sudo pip3 install fastapi
pip install fastapi --user

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3 (could also be pip3.10 depending on your version)
python3 -m pip install fastapi

# 👇️ Using py alias (Windows)
py -m pip install fastapi

# 👇️ For Anaconda
conda install -c conda-forge fastapi

# 👇️ For Jupyter Notebook
!pip install fastapi

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

# Common causes of the error

The error occurs for multiple reasons:

  1. Not having the fastapi package installed by running pip install fastapi.
  2. Installing the package in a different Python version than the one you're using.
  3. Installing the package globally and not in your virtual environment.
  4. Your IDE running an incorrect version of Python.
  5. Naming your module fastapi.py which would shadow the official module.
  6. Declaring a variable named fastapi which would shadow the imported variable.

If the error persists, get your Python version and make sure you are installing the package using the correct Python version.

shell
python --version

get python version

For example, my Python version is 3.10.4, so I would install the fastapi package with pip3.10 install fastapi.

shell
pip3.10 install fastapi

# 👇️ If you get a permissions error use pip3 (NOT pip3.X)
sudo pip3 install fastapi

Notice that the version number corresponds to the version of pip I'm using.

If the PATH for pip is not set up on your machine, replace pip with python3 -m pip:

shell
# 👇️ Make sure to use your version of Python, e.g. 3.10
python3 -m pip install fastapi

If the "No module named 'fastapi'" error persists, try restarting your IDE and development server/script.

# Check if the package is installed

You can check if you have the fastapi package installed by running the pip show fastapi command.

shell
# 👇️ Check if you have fastapi installed
pip show fastapi

# 👇️ If you don't have pip set up in PATH
python -m pip show fastapi

The pip show fastapi command will either state that the package is not installed or show a bunch of information about the package, including the location where the package is installed.

# Make sure your IDE is using the correct Python version

If the package is not installed, make sure your IDE is using the correct version of Python.

If you have multiple Python versions installed on your machine, you might have installed the fastapi package using the incorrect version or your IDE might be set up to use a different version.

For example, In VSCode, you can press CTRL + Shift + P or (⌘ + Shift + P on Mac) to open the command palette.

Then type "Python select interpreter" in the field.

python select interpreter

Then Select the correct Python version from the dropdown menu.

select correct python version

Your IDE should be using the same version of Python (including the virtual environment) that you are using to install packages from your terminal.

# Install the package in a Virtual Environment

If you are using a virtual environment, make sure you are installing fastapi in your virtual environment and not globally.

You can try creating a virtual environment if you don't already have one.

shell
# 👇️ Use the correct version of Python when creating VENV
python3 -m venv venv

# 👇️ Activate on Unix or MacOS
source venv/bin/activate

# 👇️ Activate on Windows (cmd.exe)
venv\Scripts\activate.bat

# 👇️ Activate on Windows (PowerShell)
venv\Scripts\Activate.ps1

# 👇️ Install `fastapi` in your virtual environment
pip install fastapi

If the python3 -m venv venv command doesn't work, try the following 2 commands:

  • python -m venv venv
  • py -m venv venv

Your virtual environment will use the version of Python that was used to create it.

If the error persists, make sure you haven't named a module in your project as fastapi.py because that would shadow the original fastapi module.

You also shouldn't be declaring a variable named fastapi as that would also shadow the original module.

# Try reinstalling the package

If the error is not resolved, try to uninstall the fastapi package and then reinstall it.

shell
# 👇️ Check if you have fastapi installed
pip show fastapi

# 👇️ If you don't have pip set up in PATH
python -m pip show fastapi

# 👇️ Uninstall fastapi
pip uninstall fastapi

# 👇️ If you don't have pip set up in PATH
python -m pip uninstall fastapi

# 👇️ Install fastapi
pip install fastapi

# 👇️ If you don't have pip set up in PATH
python -m pip install fastapi

Try restarting your IDE and development server/script.

You can also try to upgrade the version of the fastapi package.

shell
pip install fastapi --upgrade

# 👇️ If you don't have pip set up in PATH
python -m pip install fastapi --upgrade
If the error persists, follow the operating system-specific instructions on how to install fastapi.

# Table of Contents

  1. Install fastapi on Windows
  2. Install fastapi on macOS or Linux
  3. Install fastapi in Visual Studio Code
  4. Install fastapi in PyCharm
  5. Install fastapi in Anaconda
  6. Install fastapi in Jupyter Notebook

# Install fastapi on Windows

To install the fastapi module on Windows:

  1. Type CMD in the search bar and open the Command Prompt application.
  2. Type pip install fastapi and press Enter.
cmd
pip install fastapi

# 👇️ For Python 3
pip3 install fastapi

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3
python3 -m pip install fastapi

# 👇️ Using py alias
py -m pip install fastapi

# 👇️ If you get a permissions error
pip install fastapi --user

# 👇️ For Anaconda
conda install -c conda-forge fastapi

pip install fastapi windows

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

If the installation command doesn't succeed, try running CMD as an administrator.

Right-click on the search result, click on "Run as administrator" and run the pip install command.

run cmd as administrator

If you get the error 'pip' is not recognized as an internal or external command, use the python -m command when installing fastapi.

shell
python -m pip install fastapi

python3 -m pip install fastapi

py -m pip install fastapi

Alternatively, you can install the fastapi module in a virtual environment:

  1. Open the root directory of your project.
  2. Press Shift and right-click in Explorer.

windows open powershell window here

  1. Click on "Open PowerShell window here".
  2. Run the following commands.
PowerShell
# 👇️ Might also be: "python3 -m venv venv"
python -m venv venv

# 👇️ Activate on Windows (PowerShell)
venv\Scripts\Activate.ps1

# 👇️ Activate on Windows (cmd.exe)
venv\Scripts\activate.bat

# 👇️ Install fastapi in your virtual environment
pip install fastapi

If the python -m venv venv command doesn't work, try the following 2 commands:

  • python3 -m venv venv
  • py -m venv venv.

If you see an error message that ps1 cannot be loaded because running scripts is disabled on this system, run the following command, type "yes" when prompted and rerun the activation command.

PowerShell
Set-ExecutionPolicy RemoteSigned -Scope CurrentUser
You can verify that the fastapi module is installed by using the pip show fastapi command.
PowerShell
pip show fastapi
pip3 show fastapi

python -m pip show fastapi
python3 -m pip show fastapi

The pip show fastapi command will either state that the package is not installed or show a bunch of information about the package, including the location where the package is installed.

# Install fastapi on macOS or Linux

To install fastapi on macOS or Linux:

  1. Search for "terminal" and start the application.
  2. Type pip install fastapi and press Enter.

search for terminal

terminal
pip install fastapi

# 👇️ For Python 3
pip3 install fastapi

# 👇️ If you get a permissions error
sudo pip3 install fastapi

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3
python3 -m pip install fastapi

# 👇️ Alternative if you get a permissions error
pip install fastapi --user

# 👇️ For Anaconda
conda install -c conda-forge fastapi

macos linux install fastapi

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

If you get an error that pip isn't found, use the python -m command.

terminal
python -m pip install fastapi

python3 -m pip install fastapi

If you get a permissions error, prefix the command with sudo.

terminal
sudo pip install fastapi

sudo pip3 install fastapi

Alternatively, you can install the fastapi package in a virtual environment:

  1. Open your terminal in the root directory of your project.
  2. Run the following commands.
shell
# 👇️ Could also be "python -m venv venv"
python3 -m venv venv

# 👇️ Activate virtual env on macOS or Linux
source venv/bin/activate

# 👇️ Install `fastapi` in your virtual environment
pip install fastapi

Your virtual environment will use the version of Python that was used to create it.

If the python3 -m venv venv command doesn't work, use python -m venv venv instead.

You can use the pip show command to verify fastapi has been installed successfully.

shell
pip show fastapi
pip3 show fastapi

python -m pip show fastapi
python3 -m pip show fastapi

The pip show fastapi command will either state that the package is not installed or show a bunch of information about the package.

# Install fastapi in Visual Studio Code

To install fastapi in Visual Studio Code:

  1. Press CTRL + ` (Backtick) on your keyboard to open the terminal.
  2. Run the pip install fastapi command to install the fastapi module.
terminal
pip install fastapi

# 👇️ For Python 3
pip3 install fastapi

# 👇️ If you get a permissions error
sudo pip3 install fastapi

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3
python3 -m pip install fastapi

# 👇️ Using py alias
py -m pip install fastapi

# 👇️ Alternative if you get a permissions error
pip install fastapi --user

vscode pip install fastapi

You can also open the terminal in Visual Studio Code by pressing CTRL+Shift+P and then type "View: Toggle Terminal".

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

When installing Python modules in Visual Studio code, make sure that your IDE is configured to use the correct Python version.

Press CTRL+Shift+P or (⌘ + Shift + P on Mac) to open the command palette.

Then type "Python select interpreter" in the field.

python select interpreter

Then Select the correct Python version from the dropdown menu.

select correct python version

Your IDE should be using the same version of Python (including the virtual environment) that you are using to install packages from your terminal.

You can use the python --version command if you need to get your version of Python.

terminal
python --version
python3 --version

get python version

You can also try creating a virtual environment if you don't already have one.

terminal
# 👇️ Could also be "python -m venv venv" or "py -m venv venv"
python3 -m venv venv

# 👇️ Activate on Unix or MacOS
source venv/bin/activate

# 👇️ Activate on Windows (cmd.exe)
venv\Scripts\activate.bat

# 👇️ Activate on Windows (PowerShell)
venv\Scripts\Activate.ps1

# 👇️ Install `fastapi` in your virtual environment
pip install fastapi

Your virtual environment will use the version of Python that was used to create it.

# Install fastapi in PyCharm

To install fastapi in PyCharm:

  1. Press Alt+F12 on your keyboard to open the terminal.
  2. Run the pip install fastapi command to install the fastapi module.
terminal
pip install fastapi

# 👇️ For Python 3
pip3 install fastapi

# 👇️ If you get a permissions error
sudo pip3 install fastapi

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3
python3 -m pip install fastapi

# 👇️ Using py alias
py -m pip install fastapi

# 👇️ Alternative if you get a permissions error
pip install fastapi --user

pycharm pip install fastapi

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

Alternatively, you can use the IDE itself to install the module.

  1. Click on "File" > "Settings" > "Project" > "Python Interpreter".
  2. Click on the + icon and type fastapi.
  3. Click on "Install Package".

pycharm interpreter install fastapi

When installing Python modules in PyCharm, make sure that your IDE is configured to use the correct version of Python.

Click on "File" > "Settings" > "Project" > "Python Interpreter".

pycharm select correct interpreter

Then Select the correct Python version from the dropdown menu.

Your IDE should be using the same version of Python (including the virtual environment) that you are using to install packages from your terminal.

You can use the python --version command if you need to get your version of Python.

terminal
python --version
python3 --version

get python version

# Install fastapi in Anaconda

You can install the fastapi package with a command.

If you are on Windows, search for "Anaconda Prompt" and open the application.

If you are on macOS or Linux, open your terminal.

Run the following command to install the fastapi package.

shell
# 👇️ Using conda
conda install -c conda-forge fastapi

# 👇️ Alternatively use `pip`
pip install fastapi

# 👇️ For Python 3
pip3 install fastapi

# 👇️ If you get a permissions error
sudo pip3 install fastapi

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3
python3 -m pip install fastapi

# 👇️ Using py alias
py -m pip install fastapi

# 👇️ Alternative if you get a permissions error
pip install fastapi --user

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

Click on the following article if you need to install a specific version of the package using Anaconda.

# Install fastapi in Jupyter Notebook

To install fastapi in Jupyter Notebook:

  1. Open your terminal and type "jupyter notebook".

open jupyter notebook

  1. Click on "New" and then "Terminal" in the browser tab.

jupyter notebook click new terminal

  1. Type pip install fastapi and press Enter.
shell
# 👇️ Using pip
pip install fastapi

# 👇️ For Python 3
pip3 install fastapi

# 👇️ If you get a permissions error
sudo pip3 install fastapi

# 👇️ If you don't have pip in your PATH environment variable
python -m pip install fastapi

# 👇️ For Python 3
python3 -m pip install fastapi

# 👇️ Using py alias
py -m pip install fastapi

# 👇️ Using conda
conda install -c conda-forge fastapi

# 👇️ Alternative if you get a permissions error
pip install fastapi --user

After you install the fastapi package, you also have to install an ASGI server, such as Uvicorn.

shell
pip install "uvicorn[standard]"
pip3 install "uvicorn[standard]"

python -m pip install "uvicorn[standard]"
python3 -m pip install "uvicorn[standard]"

Here is an example taken from the fastapi docs. Create a file named main.py with the following contents.

main.py
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}

Now run the server from your terminal.

shell
uvicorn main:app --reload --port 8500

You can view your API by opening your browser at http://localhost:8500.

Alternatively, you can use the Python ipykernel.

  1. Open your terminal and type "jupyter notebook".

open jupyter notebook

  1. Click on "New" and then click on "Python 3 (ipykernel)". jupyter notebook click new ipykernel

  2. Type !pip install fastapi and click on "Run".

jupyter notebook install module

Note that the pip install command must be prefixed with an exclamation mark if you use this approach.

shell
!pip install fastapi

Once you type the command, click "Run" to install the fastapi module.

If you get a permissions error, e.g. "[WinError: 5] Access is denied", add the --user option to the installation command.

shell
!pip install fastapi --user

jupyter notebook install with user option

If the error persists, try to restart the Jupyter Kernel and rerun the command.

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