Environment Variables and Contexts

Environment variables in Deno Deploy^EA allow you to configure your application with static values such as API keys or database connection strings.

Types of environment variables Jump to heading#

Environment variables can be stored as:

• Plain text: Visible in the UI and suitable for non-sensitive values like feature flags
• Secrets: Never visible in the UI after creation, only readable from application code, suitable for sensitive values like API keys

Variables can be set at:

• Application level: Specific to a single application
• Organization level: Applied to all applications in the organization, but can be overridden by application-level variables

Contexts Jump to heading#

Each environment variable applies to one or more contexts. Contexts represent the logical "environments" in which your code runs, each with its own set of variables and secrets.

By default, there are two contexts:

• Production: Used for the production timeline serving production traffic
• Development: Used for development timelines serving non-production traffic (preview URLs and branch URLs)

Additionally, there is a Build context used during the build process. Environment variables in the Build context are only available during builds and aren't accessible in Production or Development contexts (and vice versa). This separation enables different configuration for build-time vs. runtime.

Within a single application or organization, you cannot have multiple environment variables with the same name in the same context. You can, however, have variables with the same name in different non-overlapping contexts.

Adding, editing and removing environment variables Jump to heading#

You can manage environment variables from several locations:

• On the "New App" page while creating an application
• In the application settings under the "Environment Variables" section
• In the organization settings under the "Environment Variables" section

In each location, click the relevant edit button to open the environment variables drawer. Changes only apply when you click "Save." Clicking "Cancel" discards your changes.

To add a variable:

1. Click "Add Environment Variable"
2. Enter the name and value
3. Specify whether it's a secret
4. Select the contexts where it should apply

You can also bulk import variables from a .env file:

1. Click "+ Add from .env file"
2. Paste the contents of your .env file
3. Click "Import variables"

Note that lines starting with # are treated as comments.

To remove a variable, click the "Remove" button next to it.

To edit a variable, click the "Edit" button next to it to modify its name, value, secret status, or applicable contexts.

Using environment variables in your code Jump to heading#

Access environment variables using the Deno.env.get API:

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

Predefined environment variables Jump to heading#

Deno Deploy^EA provides these predefined environment variables in all contexts:

• DENO_DEPLOYMENT_ID: A unique identifier representing the entire configuration set (application ID, revision ID, context, and environment variables). Changes if any of these components change.

• DENO_REVISION_ID: The ID of the currently running revision.

More predefined variables will be added in the future.

Note that you cannot manually set any environment variables starting with DENO_* as these are reserved system variables.

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.