umbraco-custom-maintenance-page

Custom Maintenance Page

Targets Umbraco 17 and later. The UpgradingViewPath guidance applies to Umbraco 17.3 and later, where unattended migrations run in the background. Earlier Umbraco 17 versions and other upgrade modes must follow the version specific official documentation. This is not an application error page. Use umbraco-custom-error-pages for 404, 500, and Boot Failed handling.

Choose the right Umbraco approach

Situation	Configuration or file	Guidance
Umbraco 17.3+ unattended upgrades	`Umbraco:CMS:Global:UpgradingViewPath` and a custom Razor view	Preferred for the current background upgrade flow. Point the setting at a view such as `~/Views/MyUpgrading.cshtml`.
The documented generic maintenance page convention	`UmbracoWebsite/maintenance.cshtml` at the project root	Follow the official custom maintenance page tutorial when this convention matches the project's upgrade flow and version.

Fetch the official documentation first. Do not assume the two paths are interchangeable without checking the project's Umbraco version and upgrade mode.

Choose the right hosting layer

Layer	Use when	Implementation
Umbraco runtime	Umbraco is running an upgrade or migration	`UpgradingViewPath` or the documented `UmbracoWebsite/maintenance.cshtml` convention
Umbraco Cloud platform	Cloud infrastructure or platform operations make the app unavailable	Cloud portal Error Pages feature
Hosting or web server	The app is offline, restarting, or cannot start	`app_offline.htm`, deployment slots, or a web server fallback

Do not use the Umbraco runtime page as a general deployment or app restart page. Offer the appropriate hosting layer when the user is describing ordinary deployment downtime.

Umbraco runtime implementation

Fetch the unattended upgrade documentation and the global settings documentation first for Umbraco 17.3 and later. The current unattended flow serves Upgrading.cshtml with HTTP 503 while the RuntimeLevel is Upgrading. Customize it by setting:

{
  "Umbraco": {
    "CMS": {
      "Global": {
        "UpgradingViewPath": "~/Views/MyUpgrading.cshtml"
      }
    }
  }
}

Create the configured Razor view with self contained markup. Offer assets/maintenance.cshtml as a starting template and tell the user to copy it to the configured view path, or to the root level UmbracoWebsite/maintenance.cshtml location when following the generic tutorial.

For the current Umbraco readiness flow, poll the anonymous /umbraco/api/health/ready endpoint rather than polling the front page. It returns 503 while the application is not ready and 200 when it can receive normal traffic. Do not add a custom health endpoint unless the project needs one for a separate reason.

Keep the served file self contained. Use inline CSS, no external assets, no layout, and no live Umbraco or Razor data such as IPublishedContent. The content cache or database may be unavailable while the page is being served. In particular, do not make the upgrading view query a backoffice content node for its heading or message: this creates a hard dependency on the very services that may be unavailable and can turn a useful 503 page into another failure.

Editor-controlled copy (safe compromise)

Editors can still own the wording, but the copy must be baked into the deployed view ahead of the upgrade. Create a small backoffice content node (for example, maintenanceCopy) with two required properties such as heading and message. A deployment/publish step that runs while the site is healthy reads the published values, HTML-encodes them, and replaces explicit tokens in a copy of maintenance.cshtml (for example,  and ). Deploy that generated, self-contained file to the configured UpgradingViewPath along with the application. Use safe fallback text when either value is missing.

This is not live content rendering: an editor's change takes effect on the next successful publish/deployment that regenerates the file. Keep the last known good generated file in the artifact; never require a backoffice request, IPublishedContent, a scope, or a database connection while RuntimeLevel is Upgrading. See references/editor-controlled-copy.md for the workflow and trade-offs.

The official documentation warns against keeping a project in upgrade mode longer than necessary. Test on staging with a real version upgrade path. Do not claim to have verified the page unless an actual build or upgrade test was run.

Cloud and hosting layers

For consistent branding, adapt the same self contained visual design for each layer:

Umbraco Cloud: fetch the Cloud Error Pages documentation before giving portal instructions. The page is uploaded through the portal, assigned per hostname, and must be self contained and within the documented size limit. Offer assets/cloud-error-page.html as a starter.
Azure or IIS: use app_offline.htm or deployment slots. Fetch the Azure deployment slots documentation when recommending that approach.

Cloud platform downtime and ordinary app restart downtime require a hosting layer page. They are not covered by the Umbraco runtime upgrade view.

Disabling instead

Most upgrades do not require the site to go down. If the team prefers not to show the maintenance page, add Umbraco:CMS:Global:ShowMaintenancePageWhenInUpgradeState: false in appsettings.json using the official documentation for the project's version.

Done

Tell the user:

Which Umbraco approach applies to their version and upgrade mode.
Where the configured view or maintenance file belongs.
That the page appears during upgrade state and disappears when migrations finish.
That the readiness endpoint can be used for safe automatic refresh where supported.
That Cloud platform downtime and ordinary app restart downtime need their own hosting layer.

Validation

Assertions for this skill live in evals/evals.json. Run them with the umbraco-skill-evaluator skill and validate the skill with umbraco-skill-validator and umbraco-skill-code-analyzer before shipping.