Last updated March 09, 2020

If you need to temporarily disable access to your Heroku app (for example, to perform a large migration), you can enable Heroku’s built-in maintenance mode. While in maintenance mode, your app serves a static maintenance page to all visitors.

While maintenance mode is active, the error code H80 is returned in your logs.

Usage

To enable maintenance mode:

$ heroku maintenance:on
Enabling maintenance mode for myapp... done

To disable maintenance mode:

$ heroku maintenance:off
Disabling maintenance mode for myapp... done

To check the current maintenance status of an app:

$ heroku maintenance
off

Maintenance mode and dynos

Enabling or disabling maintenance mode does not alter your app’s dyno formation. Dynos continue to accrue billing hours while in maintenance mode. Web dynos continue to run, but Heroku’s routers block all incoming HTTP requests to them. Dynos of other types (such as worker dynos) also continue to run, and you can run one-off dynos as usual.

Scaling dynos in maintenance mode

It can be useful to scale your app’s dynos to zero during maintenance operations. For example, doing so can prevent database transactions from taking place.

You can enter maintenance mode and scale your web dynos to zero like so:

$ heroku maintenance:on
Enabling maintenance mode for myapp... done
$ heroku ps:scale web=0
Scaling web processes... done, now running 0

You can do the same for your app’s other process types, such as worker.

If you scale your app’s web dynos to zero, maintenance mode’s behavior differs depending on whether your app runs in the Common Runtime or in a Private Space:

• In the Common Runtime, your maintenance page continues to be served, because it is served by a shared routing cluster.
• In a Private Space, the maintenance page is not served, because it is served by a routing proxy that resides on the same compute instances as your web dynos.

Customizing your maintenance page

You can specify a custom maintenance page for your app by setting the following config var:

heroku config:set MAINTENANCE_PAGE_URL=//s3.amazonaws.com/<your_bucket>/your_maintenance_page.html

Please see this article for more information.