How to Generate a Custom Heroku Maintenance Mode Page

I recently had to put our Content Harmony Heroku app into maintenance mode, and discovered it is possible to set a custom URL as your Maintenance Mode experience if users visit while the site is down.

This is a pretty straightforward feature, but delivers a nicer branded experience when you need to put a Heroku app into maintenance mode. We recently did this on Content Harmony both for Postgres upgrades, as well as while migrating our database to a new provider.

If you read the docs, you can set any URL as the page that is shown during maintenance mode, rather than this Heroku branded page.

So, we created a dedicated page on our marketing site (which runs on Ghost, not Rails and Heroku, so isn't affected by maintenance mode).

The page lives at /maintenance-mode, and we also added <meta name="robots" content="noindex"> to make it clear that the page should not be indexed by Google, etc.

From there, you just list that URL as a Config Var for MAINTENANCE_PAGE_URL in your Heroku settings for your app:

The page will now appear any time you run or toggle the Maintenance Mode in your App's settings: