PyCharm 2023.3 Help

FastAPI

FastAPI is a web framework for building APIs with Python. It requires the versions of Python 3.6 and later. PyCharm Professional provides the following support for developing FastAPI applications:

Create a FastAPI project

  1. In the main menu, go to File | New Project, or click the New Project button in the Welcome screen.

    Create a FastAPI project
  2. In the New Project dialog, do the following:

  3. If you want to proceed with the Project venv or Base conda interpreter, select the corresponding option and click Create.

    Project venv

    PyCharm creates a virtualenv environment based on the system Python in the project folder.

    Base conda

    PyCharm configures conda base environment as the project interpreter.

    To configure an interpreter of other type or to use an existing environment, select Custom environment.

    The following steps depend on your choice:

    Create a project with a conda environment
    • Select the Python version from the list.

    • Normally, PyCharm will detect conda installation.

      Otherwise, specify the location of the conda executable, or click Conda executable location to browse for it.

    • Specify the environment name.

    Create a project with virtualenv
    • Specify the location of the new virtual environment in the Location field, or click Virtual environment location and browse for the desired location in your file system. The directory for the new virtual environment should be empty.

    • Choose the base interpreter from the list, or click Choose the base interpreter and find the desired Python executable in your file system.

    • Select the Inherit global site-packages checkbox if you want all packages installed in the global Python on your machine to be added to the virtual environment you're going to create. This checkbox corresponds to the --system-site-packages option of the virtualenv tool.

    • Select the Make available to all projects checkbox if you want to reuse this environment when creating Python interpreters in PyCharm.

    Create a project with Pipenv

    Choose the base interpreter from the list, or click Choose the base interpreter and find the desired Python executable in your file system.

    If you have added the base binary directory to your PATH environmental variable, you don't need to set any additional options: the path to the pipenv executable will be autodetected.

    If the pipenv executable is not found, follow the pipenv installation procedure to discover the executable path, and then specify it in the dialog.

    Create a project with Poetry

    Choose the base interpreter from the list, or click Choose the base interpreter and find the desired Python executable in your file system.

    If PyCharm doesn't detect the poetry executable, specify the following path in the dialog, replacing jetbrains with your username:

    /Users/jetbrains/Library/Application Support/pypoetry/venv/bin/poetry
    C:\Users\jetbrains\AppData\Roaming\pypoetry\venv\Scripts\poetry.exe
    /home/jetbrains/.local/bin/poetry
    Selecting existing conda interpreter for a new project

    To reuse an existing conda environment:

    • Switch Type to Conda.

    • Normally, PyCharm will detect conda installation.

      Otherwise, specify the location of the conda executable, or click Conda executable location to browse for it.

    • Select the environment from the list. If you specified the path to conda manually, you may need to reload environments.

    Selecting existing interpreter for a new project

    To reuse a Virtualenv, Pipenv, or Poetry environment:

    • Switch Type to Python.

    • Select the Python executable from the list or click App expui inline browse to browse for it.

  4. Click Create.

PyCharm creates a Python environment (or reuses the existing one) and installs the fastapi and uvicorn packages. It also adds the main.py and test_main.http files with some default code constructs.

Newly created project for developing FastAPI applications

Use coding assistance to develop an application

When developing FastAPI applications, you can benefit from coding assistance available in the IDE.

  • Use inspections to analyze code problems. You can use the inspection widget to briefly preview the summary of the issues. Click the widget to get more information on each detected problem in the Problems tool window.

    Code inspections in FastAPI samples
  • You can use context-aware code completion to speed-up the coding process. Just start typing a code construct and the completion popup appears. You can also press Control+Space to show available items.

    Class completion
    Method code completion

Launch and modify run/debug configurations

  1. Once you have created a new project, PyCharm provides you with a run/debug configuration, so that you can execute your FastAPI application. The created configuration is selected in the list of the available run/debug configurations. Click Launch FastAPI run configuration in the Run widget to launch your application.

    Default run/debug configuration for FastAPI

    The target application is executed in the Run tool window. You can click the link to preview the application in a browser.

    Running FastAPI application
  2. You can modify the default run/debug configuration created with the project. Select Edit configurations... from the list of the available configurations:

    Edit Configurations

    Select the target configuration in the left pane and modify its parameters, for example, you can add more uvicorn options (in this example: --reload delay 10).

    FastAPI run/debug configuration

    For more information about working with run/debug configurations, refer to Run/debug configurations.

  3. You can also execute the .http file to test GET requests. You can run each request separately, or you can click Run all tests on the .http file toolbar to test all requests at once.

    Select an option to execute requests without an environment or create an environment in either a public or a private file.

    Run all tests

    PyCharm executes GET tests in the Services tool window. You can select a particular request to preview the summary of its execution status.

    Executing HTTP requests

    Lean more about HTTP requests in Execute HTTP requests.

Manage Endpoints

You can preview, modify, create, and test endpoints of your FastAPI application.

  1. Make sure the Endpoints plugin is enabled in the settings. Press Control+Alt+S to open the IDE settings and then select Plugins. Click the Installed tab. In the search field, type Endpoints. For more information about plugins, refer to Managing plugins.

  2. Select View | Tool Windows | Endpoints to open the Endpoints tool window.

    Alternatively, click More tool windows More tool windows on the left, and then select Endpoints.

  3. The Endpoints tool window contains the list of endpoints defined in the application.

    The dedicated pane shows the details of the selected endpotpoint including the documentation, the generated HTTP requests, and the generated OpenAPI specification.

    Double-click any item in the list of the endpoints to navigate to the corresponding method in the .py file. You can also right-click any item in the list to get a context menu with the options to navigate to the source code, find usages, generate a request in the HTTP client, or export the draft of the OpenAPI specification.

    Endpoint context menu
  4. Use coding assistance to create and modify endpoints:

    • Code completion

      PyCharm completes endpoint names as you are typing them in Python files, HTTP clients, and other project files.

      Code completion in the HTTP client
    • Live templates

      With the live templates available for HTTP clients, you can quickly modify request methods, URLs, and variables.

      Live templates for an HTTP client
    • Refactoring

      If you need to rename an endpoint, use the Rename refactoring. Select an endpoint in the editor, press Shift+F6, and type its new name.

      Renaming an endpoint

      Renaming happens in all occurrences across the project.

  5. You can preview an HTTP client in a separate tab of the editor. Click Open in Editor, and PyCharm will open a temporary scratch file with the HTTP request. You can click Run an HTTP request in the gutter to test it.

    Open an HTTP request in a separate edit tab

Last modified: 20 December 2023