App.json now supports add-on options

Change effective on 01 July 2016

We’ve added support for add-on options to the app.json manifest, used in Heroku Button apps and in review apps. This change allows you to specify options for your Heroku add-ons in button apps, and in your review apps, with the same granularity as you can on the Heroku CLI.

  • If you use add-on-specific options, such as database version numbers for Heroku PostgreSQL, you can now specify those options using the options key for each add-on. Your review apps will better mirror your production environment.
  • If you have multiple add-ons of the same type, such as multiple databases, in your application, app.json can now give those add-ons predictable names using the as key. Review apps and button apps will no longer need additional code to locate secondary databases in the environment.

To use this feature in your app.json manifest, specify each add-on as a JSON object, rather than a string, as in this example:

{
  …
  "addons": [
    {
      "plan": "heroku-postgresql",
      "as": "BACKUP_DATABASE",
      "options": {
        "version": "9.5"
      }
    }
  ]
}

For complete documentation, see