Deployment previews

Deployment previews let you preview your Custom Application changes using a unique URL.

To test your Custom Application features before releasing them to the production environment, you can add a deployment preview. For example, you can add a deployment preview to try new features in your Custom Application's staging branch.

You must host the deployment previews separately from one another and assign a unique but static URL. You can add as many deployment previews as you like. In Merchant Center, the deployment previews are available on a unique URL, different than the production environment.

This document describes the necessary steps to build and add deployment previews to your Custom Application. The process involves:

  1. Building a deployment preview for your Custom Application.
  2. Deploying a Custom Application preview to your hosting provider.
  3. Adding a deployment preview to the Custom Application settings.

Building a deployment preview

Each deployment preview has its unique and static deployment URL. The Merchant Center uses this URL to render the deployment preview. Therefore, to build a deployment preview, you must set the env.production.url value to deployed application's URL in the custom-application-config.json file.

To build a deployment preview, configure your production URL in the custom-application-config.json file using the environment variables references.

"env": {
"production": {
"url": "${env:APP_URL}",

With the above setup, you can build deployment previews based on the APP_URL environment variable value. How you set the environment is up to you. For example, you could set the APP_URL to different values in different hosting environments or create a .env file in your project and commit different values for the APP_URL variable in different branches.

Deploying a Custom Application preview

Once you've built your Custom Application using the correct env.production.url value. You can deploy the Custom Application preview the same way you deploy your Custom Application. The only requirement is that the deployed application URL (APP_URL) is static, so you can specify it in the Merchant Center when adding the deployment preview.

You must set the APP_URL environment variable on your hosting provider.

See Deployment Examples to get up and running with some of the common cloud hosting providers.

Adding a deployment preview to the Custom Application

To use the Custom Application deployment preview inside the Merchant Center, you must add the deployment preview in your Custom Application settings. When adding the deployment preview, you'll need to fill the APP_URL value in the Application URL field.

For example, you can add a deployment preview hosted at by setting the APP_URL environment variable to in the staging deployment environment and using as the Application URL when adding the deployment preview in the Merchant Center.