Environment variables

Environment variables are useful to store values like access tokens of web services. Each deployment has a set of environment variables defined at the moment of creation and accessible from the code via the Deno.env API. There are 2 ways to define the environment variables of a deployment:

Project environment variables

You can define environment variables at the project level. When you create a deployment, it will get the set of environment variables the the project has defined at that particular moment.

For convenience, When you change the environment variables of a project, the current production deployment is redeployed, creating a new production deployment with the new set of environment variables.

note

Deployments are immutable, including their environment variables. Changing the environment variables of a project does not change the environment variables of existing deployments.

To add an environment variable to your project, click on the Settings button on the project page and then on Environment Variables from the sidebar. Fill in the key/value fields and click on "Add" to add an environment variable to your project.

Deployment environment variables

When deploying using deployctl, you can specify environment variables using the --env or --env-file flags, complementing the environment variables already defined for the project. These env variables will be specific for the deployment being created.

Default environment variables

Every deployment has the following environment variables preset, which you can access from your code.

1. DENO_REGION

   It holds the region code of the region in which the deployment is running. You can use this variable to serve region-specific content.

   You can refer to the region code from the regions page.

2. DENO_DEPLOYMENT_ID

   It holds the ID of the deployment.