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Assign aliases and promote to production

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Learn about deployment URLs and how to set up aliases.

Deployments

Deployments to EAS Hosting are immutable. Each deployment is accessible via a unique deployment URL consisting of the preview subdomain name and the deployment ID.

Preview subdomain name

To activate EAS Hosting for a project, you'll need to choose a preview subdomain name. You can do this via the Hosting section of your project on the expo.dev website. Alternatively, you'll be prompted to choose a preview subdomain when you create your first deployment using the EAS CLI.

Preview and production URLs

A preview subdomain name is a prefix used for the preview URL of your app. For example, if you choose my-app as the preview subdomain name, your preview URL would be: https://my-app--or1170q9ix.expo.app/, and your production URL would be: https://my-app.expo.app/.

Deployment ID

Each deployment is identifiable using a unique deployment ID. This ID can be customized but will be a random string of letters and numbers by default.

Deployments are immutable. Once they are deployed, they cannot be changed and will always remain accessible and identifiable using their deployment ID.

Aliases

Aliases are user-defined values used for creating custom URLs for deployments.

To make a deployment and assign it to an alias, use the --alias option:

Terminal
- eas deploy --alias hello

The above command will create a deployment with both a standard URL at https://my-app--or1170q9ix.expo.app/ and an alias at https://my-app--hello.expo.app/.

Aliases are unique per project. If you choose an alias that was already in use, it will get re-assigned to the new deployment.

A single deployment can have multiple aliases. Aliases can also be assigned to an existing deployment by using the --id option:

Terminal
- eas deploy:alias --id=my-id

In the above command, the my-id is the ID in the preview URL.

Aliases can have arbitrary names. For example, if you want to create a staging environment, you may create an alias called staging and assign a deployment to it.

Production alias

If your preview subdomain name is my-app, your production URL will be https://my-app.expo.app/.

Similar to other aliases, a deployment can be promoted to production using --prod option:

Terminal
- eas deploy --prod

Existing deployment can also be promoted to production using its deployment ID with the --id option:

Terminal
- eas deploy:alias --prod --id=deploymentId

Terminology

In the following example, my-app is selected as the preview subdomain name:

  • https://my-app--or1170q9ix.expo.app/ : Preview URL, which is unique and where your deployment is available.
    • my-app: Preview subdomain name. Globally unique prefix tied to your project.
    • or1170q9ix: Deployment ID, which is unique to this deployment.
  • https://my-app--hello.expo.app/: A deployment URL with an alias.
    • hello: User-defined alias.
  • https://my-app.expo.app/: Production deployment URL.