Environment Variables and Contexts

In Deno Deploy^EA, environment variables can be used to configure an application using some static values, such as API keys or database connection strings.

Environment variables can either be stored as a plain text value, or as a secret. Plain text values are visible from the UI and should be used for non-sensitive values such as feature flags. Secrets are never visible from the UI and can only be read in plain text from the application code. Secrets should be used for sensitive values such as API keys.

Environment variables can be set either at the application level or at the organization level. Application-level environment variables are set for a specific application, while organization-level environment variables are set for the entire organization. Organization-level environment variables are inherited by all applications in the organization, but can be overridden by application-level environment variables.

Each environment variable applies to one or more contexts. Contexts are the logical "environments" in which your code runs. Each context has its own set of environment variables and secrets. By default, there are two contexts:

• Production: The production context is used for the production timeline, which serves production traffic.

• Development: The development context is used for the development timeline, which serves all non-production traffic. This is used for preview URLs and branch URLs.

Inside of an application or organization, you can not have multiple environment variables with the same name that apply to the same context. It is possible to have multiple environment variables with the same name that apply to different contexts, as long as the contexts do not overlap.

Adding, editing and removing environment variables Jump to heading#

There are multiple places to add environment variables:

• On the "New App" page while creating a new application, by clicking on the "Add/Edit Environment Variables" button.

• In the application settings page in the "Environment Variables" section, by clicking on the "Edit" button.

• In the organization settings page in the "Environment Variables" section, by clicking on the "Edit" button.

The environment variables drawer will open, where you can add or remove environment variables. Any changes made in the environment variables drawer will be applied only once you click on the "Save" button. If you want to discard your changes, you can click on the "Cancel" button to close the drawer without saving.

To add a new environment variable, click on the "Add Environment Variable" button and fill in the name, value, whether it is a secret, and the contexts in which it should be applied.

It is also possible to bulk add multiple environment variable by importing a .env file. To do this, click on the "+ Add from .env file" in the environment variable drawer, paste in the .env file contents, and click "Import variables". Lines starting with # are ignored as comments.

To remove an environment variable, click on the "Remove" button next to the environment variable you want to remove.

To edit an environment variable, click on the "Edit" button next to the environment variable you want to edit. You can change the name, value, make a plain text variable a secret, and edit the contexts in which it should be applied.

To save your changes, click on the "Save" button. If you want to discard your changes, you can click on the "Cancel" button to close the drawer without saving.

Using environment variables in your code Jump to heading#

Environment variables can be accessed in your code using the Deno.env.get API.

For example, to access the MY_ENV_VAR environment variable, you can use the following code:

const myEnvVar = Deno.env.get("MY_ENV_VAR");

Predefined environment variables Jump to heading#

Deno Deploy^EA provides a set of predefined environment variables that are automatically set for each application. These environment variables are available in all contexts and can be used to access information about the application and the environment in which it is running.

• DENO_DEPLOYMENT_ID - A unique identifier that represents the entire set of configuration that the application is running in. This includes the application ID, the revision ID, the context, and any applicable environment variables. This value changes if any of the above change.

• DENO_REVISION_ID - The revision ID that is currently running.

More predefined environment variables will be added in the future.

It is not possible to manually set any environment variables that start with DENO_*. These environment variables are set by Deno Deploy^EA and are read-only.