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When Domino publishes and runs an App, it injects useful metadata into the runtime environment. These values can help your App adjust its behavior based on user identity, routing, project settings, or access controls.

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Request headers

Domino includes several custom HTTP headers in each request forwarded to your App. These headers are only available if your app framework supports proxied HTTP headers.
These headers are supported by Dash and Flask by default. For Shiny, you must use Shiny Server Pro to receive them.

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Environment variables

Domino also injects runtime environment variables when an App is started. These are available to your app logic at startup. Additional environment variables may be defined at the project or user level:
  • Project-level variables: Defined in the project settings.
  • User-level variables: Tied to the user who starts the App.
These variables can be used to:
  • Configure your App’s route prefix programmatically.
  • Apply logic based on project context or user configuration.
  • Pass secrets or credentials securely (via Domino’s environment variable management).

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Next steps

  • Apps in Domino gives an overview of how apps work within the Domino ecosystem.
  • Learn more about how Apps in Domino run and what identity and permissions are used.
  • Create and Publish an App has instructions on creating and publishing your Apps, customizing the App’s URL, and sharing Apps with authorized users.