Global variables

Use global variables to store and reuse credentials and generic values across all of your flows. Global variables are typically used by components in flow, and you can use them in any field with the global variable icon.

In contrast, environment variables, like LANGFLOW_PORT or LANGFLOW_LOG_LEVEL, are generally for broader settings that configure how Langflow runs. However, Langflow can also source global variables from environment variables.

Langflow stores global variables in its internal database, and it encrypts the values using a secret key.

Create a global variable

To create a new global variable, follow these steps.

1. In the Langflow header, click your profile icon, and then select Settings.

2. Click Global Variables.

3. Click Add New.

4. In the Create Variable dialog, enter a name for your variable in the Variable Name field.

5. Optional: Select a Type for your global variable. The available types are Generic (default) and Credential.

   Langflow encrypts both Generic and Credential type global variables. However, Generic variables aren't masked in the visual editor, whereas Credential variables are masked. Session ID fields don't accept Credential (masked) variables.

6. Enter the Value for your global variable.

7. Optional: Use the Apply To Fields menu to select one or more fields that you want Langflow to automatically apply your global variable to. For example, if you select OpenAI API Key, Langflow automatically applies the variable to any OpenAI API Key field.

8. Click Save Variable.

You can now select your global variable from any text input field that displays the Globe icon.

Edit a global variable

1. In the Langflow header, click your profile icon, and then select Settings.

2. Click Global Variables.

3. Click on the global variable you want to edit.

4. In the Update Variable dialog, you can edit the following fields: Variable Name, Value, and Apply To Fields.

5. Click Update Variable.

Delete a global variable

Deleting a global variable permanently deletes the value from the database. Flows that reference the deleted global variable will fail.

1. In the Langflow header, click your profile icon, and then select Settings.

2. Click Global Variables.

3. Click the checkbox next to the global variable that you want to delete.

4. Click Delete.

The global variable is deleted from the database.

Add custom global variables from the environment

Langflow can source custom global variables from your runtime environment. For information about how Langflow detects and applies environment variables, see Langflow environment variables.

Langflow automatically generates global variables based on constants.py if it detects any matching environment variables. For example, if you set OPENAI_API_KEY in your runtime environment, Langflow automatically generates a global variable using that value.

You can declare additional variables in LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT. For example, LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT=WATSONX_PROJECT_ID,WATSONX_API_KEY creates global variables named WATSONX_PROJECT_ID and WATSONX_API_KEY in Langflow's database. Then, you can use these variables wherever they are needed in your component settings.

Local

If you installed Langflow locally, set LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT in your Langflow .env file:

1. Create or edit your Langflow .env file.

2. Add the LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT environment variable as follows:

   You can specify the variables either as a comma-separated string with no spaces, or as a JSON list:

   
   

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   # Option 1: Comma-separated string (no spaces)

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   LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT=VARIABLE1,VARIABLE2

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   # Option 2: JSON list format

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   LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT=["VARIABLE1", "VARIABLE2"]

   
   

   Replace VARIABLE1,VARIABLE2 with your additional variables that you want Langflow to source from the environment, such as CUSTOM_API_KEY,INTERNAL_SERVICE_URL or ["CUSTOM_API_KEY", "INTERNAL_SERVICE_URL"].

3. Save and close the file.

4. Start Langflow with the .env file:

   
   

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   uv run langflow run --env-file .env

   
   

   Alternatively, you can set environment variables directly in the command line:

   
   

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   VARIABLE1="VALUE1" VARIABLE2="VALUE2" uv run langflow run --env-file .env

   
   

   The command-line variables override matching variables in the .env file. Expose your environment variables to Langflow in a manner that best suits your own environment.

5. Confirm that Langflow successfully sourced the global variables from the environment:

   1. In the Langflow header, click your profile icon, and then select Settings.

   2. Click Global Variables, and then make sure that your environment variables appear in the Global Variables list.

Docker

If you're using Docker, there are two ways that you can set LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT:

• On the command line:

  
  

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  docker run -it --rm \

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  -p 7860:7860 \

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  -e LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT="VARIABLE1,VARIABLE2" \

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  -e VARIABLE1="VALUE1" \

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  -e VARIABLE2="VALUE2" \

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  langflowai/langflow:latest

  
  

• In your .env file:

  
  

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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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  -e VARIABLE1="VALUE1" \

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  -e VARIABLE2="VALUE2" \

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  langflowai/langflow:latest

  
  

The list in LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT includes only the variable names. You must ensure that these environment variables are defined in your Docker environment, such as with -e or otherwise.

After starting Langflow, go to your Langflow Settings to confirm that the variables were created.

Only the Name and Value are taken from the environment. You can edit the variables in your Langflow Settings if you want to configure additional options, such as the Apply To Fields option.

Global variables sourced from the environment are assigned the Credential type, which masks the values in the visual editor. However, Langflow automatically encrypts all global variables stored in the database.

Disallow global variables from the environment

If you want to explicitly prevent Langflow from sourcing global variables from the environment, set LANGFLOW_STORE_ENVIRONMENT_VARIABLES=False in your .env file.

Use environment variables for missing global variables

If you want to automatically set fallback values for your global variables to environment variables, set LANGFLOW_FALLBACK_TO_ENV_VAR=True in your .env file. When this setting is enabled, if a global variable isn't found, Langflow attempts to use an environment variable with the same name as a backup.

For example, assume you have the following Langflow .env configuration, and your flow has a component that expects a WATSONX_API_KEY global variable:

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LANGFLOW_FALLBACK_TO_ENV_VAR=True

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WATSONX_PROJECT_ID=your_project_id

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WATSONX_API_KEY=your_api_key

When you run the flow, if there is no global variable named WATSONX_API_KEY, Langflow looks for an environment variable named WATSONX_API_KEY. In this example, Langflow uses the WATSONX_API_KEY value from the .env to run the flow.