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Global variables

Global variables let you store and reuse generic input values and credentials across your projects. You can use a global variable in any text input field that displays the icon.

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

Create a global variable​

To create a new global variable, follow these steps.

  1. In the Langflow UI, 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. The difference is in how the variables are displayed in the UI.

    Global variables of the Generic type are displayed in a standard input field with no masking.

    Global variables of the Credential type are hidden in the UI and entered in a password-style input field that masks the value. They are also not allowed in session ID fields, where they would be exposed. All default environment variables and variables sourced from the environment using LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT are automatically set as Credential type global 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 icon.

Edit a global variable​

  1. In the Langflow UI, 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​

warning

Deleting a global variable permanently deletes any references to it from your existing projects.

  1. In the Langflow UI, 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 the Trash icon.

The global variable, and any existing references to it, are deleted.

Add custom global variables from the environment​

You can use the LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT environment variable to source custom global variables from your runtime environment. All global variables sourced from the environment are automatically set as Credential type global variables.

Langflow's default global variables are already included in this list and are automatically sourced when detected. You can extend this list by setting LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT with your additional variables.

If you installed Langflow locally, you must define the LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT environment variable in a .env file.

  1. Create a .env file and open it in your preferred editor.

  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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    _10
    # 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 my_key,some_string or ["my_key", "some_string"]. These are added to the default list of variables that Langflow already monitors.

  3. Save and close the file.

  4. Start Langflow with the .env file:


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

    note

    In this example, the environment variables (VARIABLE1="VALUE1" and VARIABLE2="VALUE2") are prefixed to the startup command. This is a rudimentary method for exposing environment variables to Python on the command line, and is meant for illustrative purposes. Make sure to 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 UI, click your profile icon, and then select Settings.

    2. Click Global Variables.

    The environment variables appear in the list of Global Variables.

info

When adding global variables from the environment, the following limitations apply:

  • You can only source the Name and Value from the environment. To add additional parameters, such as the Apply To Fields parameter, you must edit the global variables in the Langflow UI.

  • Global variables that you add from the environment always have the Credential type.

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


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LANGFLOW_STORE_ENVIRONMENT_VARIABLES=false

If you want to automatically set fallback values for your global variables from environment variables, set the LANGFLOW_FALLBACK_FROM_ENV_VAR environment variable to true in your .env file. When this feature is enabled, if a global variable is not found, Langflow attempts to use an environment variable with the same name as a fallback.


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LANGFLOW_FALLBACK_FROM_ENV_VAR=true

Default environment variables​

Langflow automatically detects and converts some environment variables into global variables of the type Credential, which are applied to the specific fields in components that require them. Currently, the following variables are supported:

  • ANTHROPIC_API_KEY
  • ASTRA_DB_API_ENDPOINT
  • ASTRA_DB_APPLICATION_TOKEN
  • AWS_ACCESS_KEY_ID
  • AWS_SECRET_ACCESS_KEY
  • AZURE_OPENAI_API_DEPLOYMENT_NAME
  • AZURE_OPENAI_API_EMBEDDINGS_DEPLOYMENT_NAME
  • AZURE_OPENAI_API_INSTANCE_NAME
  • AZURE_OPENAI_API_KEY
  • AZURE_OPENAI_API_VERSION
  • COHERE_API_KEY
  • COMPOSIO_API_KEY
  • GOOGLE_API_KEY
  • GROQ_API_KEY
  • HUGGINGFACEHUB_API_TOKEN
  • NOVITA_API_KEY
  • OPENAI_API_KEY
  • PINECONE_API_KEY
  • SAMBANOVA_API_KEY
  • SEARCHAPI_API_KEY
  • SERPAPI_API_KEY
  • TAVILY_API_KEY
  • UPSTASH_VECTOR_REST_TOKEN
  • UPSTASH_VECTOR_REST_URL
  • VECTARA_API_KEY
  • VECTARA_CORPUS_ID
  • VECTARA_CUSTOMER_ID

For information about other environment variables and their usage, see Environment Variables.

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