Mobile SEO · Research note
Why the Web Page Stays Canonical When You Have an App
An app does not replace the web page behind it. Universal links and App Links are web addresses that fall back to your site, Google indexes the mobile web version of a page, and Firebase now calls its app content indexing no longer the recommended approach. The page at each app route is what search engines and every visitor without the app will see.
Scope and limits
This note draws on Google, Apple and Firebase documentation. It does not cover other search engines' handling of app content and makes no claim about rankings.
One address, two destinations
Universal links and App Links are built on a simple idea: the same https address serves the app and the website. Apple puts it this way: "one URL works for both your website and your app. If the person hasn't installed your app, the system opens the URL in their default web browser, allowing your website to handle it." Whoever opens that URL without the app, a new visitor, a visitor outside a licensed market, a crawler, gets the web page. If the page is thin, so is their experience.
What search engines index
Google's own description of mobile-first indexing is that it uses "the mobile version of a site's content, crawled with the smartphone agent, for indexing and ranking." Content that exists only inside an app is not part of that. Firebase, which once offered a way to index in-app content, now says Firebase App Indexing is "no longer the recommended way of indexing content for display as suggested results," and warns that "The Google Search App for Android no longer uses local content indexed via Firebase App Indexing." Its recommended alternatives for linking users to app content are universal links and App Links, both of which depend on a real web page at the same address. Age and location gates are a separate question, covered in age gates, location checks and crawling.
Pages that must stay on the web
| Page type | Why it stays on the web |
|---|---|
| Operator, license and contact details | Visitors and regulators must be able to see who runs the service, with or without the app |
| Terms, privacy and complaints | Needed before anyone installs or signs up |
| Safer gambling information | Google Play requires responsible gambling information in the app and listing; the same help must reach people who never install |
| Help articles | A help answer should be readable without an install, including from a search result |
| Event, market and promotion pages linked from outside | Their URLs are the app links; without the app, the page is the destination |
Putting it into practice
- For every route in your association files, open the URL in a private browser window on a phone. If the page does not do the job without the app, fix the page before promoting the link.
- Use exclusions to keep help and safer gambling paths on the web even when the app is installed.
- Keep titles, descriptions and structured data on these pages consistent between mobile and desktop, as the mobile-first indexing guide explains.
- If you retired Firebase Dynamic Links or App Indexing, check that nothing in your SEO plan still assumes them; the migration guide covers the replacement.
The whole route from search result to app screen, and the decision points along it, are mapped in the search to app note.
Questions
Should every app screen have a web equivalent?
Every screen you link to from outside the app should, because that same address is what people without the app, and search engines, will open. Screens reached only inside the app, such as settings, do not need one.
Does Firebase App Indexing still put app content into search?
Firebase says it is no longer the recommended way of indexing content for display as suggested results, and that the Google Search app for Android no longer uses local content indexed through it.
Which pages should never be app-only for a gambling brand?
Licensing and operator details, terms and privacy, complaints, help articles and safer gambling information, including help lines and self-exclusion routes.
Sources
- Google Search Central, Mobile-first Indexing Best Practices, last updated December 10, 2025.
- Apple Developer, Allowing apps and websites to link to your content, no date shown.
- Firebase, Firebase App Indexing, last updated October 27, 2026.
- Google Play Console Help, Real-Money Gambling, Games, and Contests, no date shown.
How we choose and date sources: data sources.