PyCharm 2026.1 Help

Run/Debug Configuration: Flask Server

Create: Run | Edit Configurations | Add New Configuration | Flask Server

Use this dialog to create a run / debug configuration for the Flask server and customize the way PyCharm executes your Flask application.

See Creating web applications with Flask for more details on using Flask in PyCharm.

Select Run | Edit Configurations from the main menu, then click Add a new configuration and select the Flask server template.

Flask run/debug configuration

Configure the run/debug configuration parameters. Some optional parameters are hidden. To view and enable them, click the Modify options link.

Optional parameters

Toolbar

The tree view of run/debug configurations has a toolbar that helps you manage configurations available in your project as well as adjust default configurations templates.

Item

Shortcut

Description

the Add button

Alt+Insert

Create a run/debug configuration.

the Remove button

Alt+Delete

Delete the selected run/debug configuration. Note that you cannot delete default configurations.

Copy

Ctrl+D

Create a copy of the selected run/debug configuration. Note that you create copies of default configurations.

Save configuration

The button is displayed only when you select a temporary configuration. Click this button to save a temporary configuration as permanent.

Move into new folder / Create new folder

Move into new folder / Create new folder. You can group run/debug configurations by placing them into folders.

To create a folder, select the configurations within a category, click Folder, and specify the folder name. If only a category is in focus, an empty folder is created.

Then, to move a configuration into a folder, between the folders or out of a folder, use drag or Move Up and Move Down buttons.

To remove grouping, select a folder and click Remove Configuration.

Sort configurations

Click this button to sort configurations in the alphabetical order.

Common options

Item

Description

Name

Specify a name for the run configuration to quickly identify it among others when editing or running.

Store as project file

Save the file with the run configuration settings to share it with other team members. The default location is .idea/runConfigurations. However, if you do not want to share the .idea directory, you can save the configuration to any other directory within the project.

By default, it is disabled, and PyCharm stores run configuration settings in .idea/workspace.xml.

Flask Server-specific options

Item

Description

Python Interpreter

Select one of the pre-configured Python interpreters from the list.

Note that you can select a remote interpreter as well as the local one.

Module/Script/Custom

Choose one of the following methods from the dropdown to construct and pass the FLASK_APP variable to Flask:

  • Module – by using a Python module name and a Flask class instance.

  • Script – by using a path to a Python file.

  • Custom – by using an arbitrary combination of paths, modules, and Flask class instances.

For more information about the FLASK_APP variable, refer to Flask CLI documentation.

Target

Depending on the method you selected previously, you can specify the following values:

  • Path to the Python file, for example, /Users/jetbrains/MyFlaskProject/app.py. You can type in the path or click the the Browse button button to locate the file in the project structure.

  • Name of the module in the Flask project, for example, access_management. You can type in the module name or click the the Browse button button to search the target module by its name or to locate it in the project structure.

  • Custom combination of modules, scripts, and Flask class instances, for example, access_management.access:app2, where:

    • access_management – the module name

    • access – the target file in the module

    • app2 – the Flask class instance in access.

Working directory

Specify a directory to be used by the running task.

  • When a default run/debug configuration is created by the keyboard shortcut Ctrl+Shift+F10, or by choosing Run from the context menu of a script, the working directory is the one that contains the executable script. This directory may differ from the project directory.

  • When this field is left blank, the bin directory of the PyCharm installation will be used.

Environment variables

This field shows the list of environment variables. If the list contains several variables, they are delimited with semicolons.

By default, the field contains the variable PYTHONUNBUFFERED set to 1. To fill in the list, click the browse button, or press Shift+Enter and specify the desired set of environment variables in the Environment Variables dialog.

To create a new variable, click the Add button, and type the desired name and value.

You might want to populate the list with the variables stored as a series of records in a text file, for example:

Variable1 = Value1 Variable2 = Value2

Just copy the list of variables from the text file and click Paste (Paste) in the Environmental Variables dialog. The variables will be added to the table. Click Ok to complete the task. At any time, you can select all variables in the Environment Variables dialog, click Copy Copy, and paste them into a text file.

Paths to ".env" files

This field shows paths to .env files with environment variables. If there are several files, the paths to them are delimited with semicolons.

To manage the list of .env files, click Choose ".env" file. In the Environment Files dialog that opens, use Add and Remove to add and remove files.

You can also use and to change the order in which .env files are loaded.

Flask env

An environment variable set to one of the possible environments. The default value is 'development'.

Add content roots to PYTHONPATH

Select this checkbox to add all content roots of your project to the environment variable PYTHONPATH.

Add source roots to PYTHONPATH

Select this checkbox to add all source roots of your project to the environment variable PYTHONPATH.

Additional options

Click Modify options and select the options that you want to add to the dialog.

Operating System

Item

Description

Allow multiple instances

Allow running multiple instances of this run configuration in parallel.

By default, it is disabled, and when you start this configuration while another instance is still running, PyCharm suggests stopping the running instance and starting another one. This is helpful when a run configuration consumes a lot of resources and there is no good reason to run multiple instances.

Python

Item

Description

Interpreter options

In this field, specify the command-line options to be passed to the interpreter. If necessary, click Expand the field, and type the string in the editor.

Debug

Item

Description

Debug just my code

When this option is enabled, the debugger focuses only on user-written code and skips stepping into external libraries.

Flask

Item

Description

Flask application

The target Flask class instance to be executed. This value will be put into the FLASK_APP variable during the execution. For example, you've declared the following instance of the Flask class in your application:

app = Flask(__name__);

Then you can add app into the Application field. It is typically used for the Module name target type. For Script path, the Application field is enabled only for the Flask version 0.13 and later. The field is disabled for the Custom target type, because you can specify the required instance in the combination added to the Target field.

Additional options

Parameters of the flask run command.

--host – the IP address of the web server to run your Flask application on. The default value is '127.0.0.1'. To make your web server externally visible, use the '0.0.0.0' value for this parameter.

--port – the port of the web server. The default value is 5000 or it is the port number set in the SERVER_NAME config variable.

Example: --host=127.0.0.2 --port=1234.

Logs

The following options are related to logging the execution of this configuration. For more information, refer to Setting log options.

Item

Description

Specify logs to be shown in the console

Specify which log files to display while running the application.

Click the Add button to add a new log. In the Edit Log Files Aliases dialog, configure the following:

  • Alias: The name of the tab where the log will be displayed.

  • Log File Location: Specify the path to the log file or an Ant pattern. If several files of a rolling log match the pattern, PyCharm will display the most recent one.

  • Show all files coverable by pattern: Show all logs that match the pattern.

For logs in the table, you can configure the following options:

  • Is Active: Display the specified log file.

  • Skip Content: Do not display old log messages from previous runs.

Save console output to file

Save the console output to the specified location. Type the path manually or click the browse button and point to the desired location in the dialog that opens.

Show console when a message is printed to stdout

Activate the console when the application writes to the standard output stream.

Show console when a message is printed to stderr

Activate the console when the application writes to the standard error stream.

Before launch

Item

Description

Add before launch task

Select this option to add one of the following available tasks:

  • Launch Web Browser: select this option to have a browser started. In the dialog that opens, select the type of the browser and provide the start URL. Also, specify if you want the browser to be launched with the JavaScript debugger.

  • Run External tool: select to run an external application. In the dialog that opens, select one or multiple applications you want to run. If it is not defined in PyCharm yet, add its definition. For more information, refer to External tools and External Tools.

  • Run Another Configuration: select to execute another run/debug configuration and wait until it finishes before starting the current configuration. If you want to run several configurations in parallel, use a compound run/debug configuration.

  • Run File Watchers: select this option to have PyCharm apply all the currently active File Watchers.

  • Run Remote External Tool: adds a remote SSH external tool.

  • Run Grunt task: select this option to run a Grunt task.

    In the Grunt task dialog that opens, specify the Gruntfile.js where the required task is defined, select the task to execute, and specify the arguments to pass to the Grunt tool.

    Specify the location of the Node.js runtime, the parameters to pass to it, and the path to the grunt-cli package.

  • Run gulp task: select this option to run a Gulp task.

    In the Gulp task dialog that opens, specify the Gulpfile.js where the required task is defined, select the task to execute, and specify the arguments to pass to the Gulp tool.

    Specify the location of the Node.js runtime, the parameters to pass to it, and the path to the gulp package.

  • Run npm script: select this option to execute an npm script.

    In the NPM Script dialog that opens, specify the npm run/debug configuration settings.

  • Compile TypeScript: select to run the built-in TypeScript compiler and thus make sure that all the changes you made to your TypeScript code are reflected in the generated JavaScript files. In the TypeScript Compile Settings dialog that opens, select or clear the Check errors checkbox to configure the behaviour of the compiler in case any errors are detected:

    • If the Check errors checkbox is selected, the compiler will show all the errors and the run configuration will not start.

    • If the Check errors checkbox is cleared, the compiler will show all the detected errors but the run configuration still will be launched.

  • Disconnect Data Source: select this option if you want to disrupt the connection to a data source before the run/debug configuration is run.

Open run/debug tool window when started

By default this option is selected and the Run or the Debug tool window opens when you start the run/debug configuration.

Otherwise, the tool window is hidden. However, when the configuration is running, you can open the corresponding tool window for it yourself by pressing Alt+4 or Alt+5.

Focus run/debug tool window when started

Select this option to automatically move focus to the Run or the Debug tool window when you start the run/debug configuration.

Show the run/debug configuration settings before start

Select this option to show the run/debug configuration settings prior to actually starting the run/debug configuration.

02 March 2026
Creating Web Applications with FlaskManage Endpoints