Configuration

Reflex apps can be configured using a configuration file, environment variables, and command line arguments.

Configuration File

Running uv run reflex init will create an rxconfig.py file in your root directory. You can pass keyword arguments to the Config class to configure your app.

For example:

python

# rxconfig.py
import reflex as rx

config = rx.Config(
    app_name="my_app_name",
    # Connect to your own database.
    db_url="postgresql://user:password@localhost:5432/my_db",
    # Change the frontend port.
    frontend_port=3001,
)

See the config reference for all the parameters available.

Environment Variables

You can override the configuration file by setting environment variables. For example, to override the frontend_port setting, you can set the FRONTEND_PORT environment variable.

bash

FRONTEND_PORT=3001 uv run reflex run

Command Line Arguments

Finally, you can override the configuration file and environment variables by passing command line arguments to uv run reflex run.

bash

uv run reflex run --frontend-port 3001

See the CLI reference for all the arguments available.

Customizable App Data Directory

The REFLEX_DIR environment variable can be set, which allows users to set the location where Reflex writes helper tools like Bun and NodeJS.

By default we use Platform specific directories:

On windows, C:/Users/<username>/AppData/Local/reflex is used.

On macOS, ~/Library/Application Support/reflex is used.

On linux, ~/.local/share/reflex is used.