Deep Link
Also known as: deep linking, app deep link, deep link
A deep link is a URL that opens a specific screen inside an app rather than its home screen—for example a link that jumps straight to a cleanup or duplicate-photos view. Verified web-domain deep links are called Universal Links (iOS) and App Links (Android).
- Opens a specific in-app screen via a URI, not just the app's home screen.
- Verified web-domain forms are Universal Links on iOS (AASA file) and App Links on Android (assetlinks.json).
- Deferred deep linking honors a link captured before install once the app is installed.
What a deep link is
A deep link is a URI that routes the user to a precise location inside an app instead of just launching it. The URI carries enough information—a path and often query parameters—for the app to render a particular screen, such as a specific photo album, a large-files report, or a settings panel. This is the in-app equivalent of linking to a sub-page on a website rather than the homepage.
Deep links come in two broad flavors: custom-scheme links (e.g. `cleanor://cleanup/duplicates`), which only work if the app is installed and aren't tied to a real domain; and verified web links that use `https://` and a domain the developer owns. The verified kind is more robust because the OS can confirm the domain truly belongs to the app.
Universal Links and App Links
On iOS/iPadOS, verified deep links are Universal Links: the app declares `Associated Domains` and the website hosts an `apple-app-site-association` (AASA) file proving ownership. Tapping such an `https` link opens the app directly if installed, or falls back to the website otherwise—no chooser, no fragile scheme.
On Android, the equivalent is App Links: an `https` deep link with `android:autoVerify="true"` on its intent filter, backed by an `assetlinks.json` file at `/.well-known/` on the domain. Verified App Links bypass the app-chooser dialog. Plain custom-scheme intents still work but can trigger a disambiguation prompt and are easier to hijack, which is why verified links are preferred for production routing.
Why it matters for a cleaner app
Deep links let a storage cleaner route users straight into the screen that matters: a marketing email or push notification can link to the duplicate photos scanner or the large files view, skipping the onboarding flow. They also power 'continue where you left off' and re-engagement campaigns.
A related concept is deferred deep linking, where a link captured before install is honored after the user installs the app—useful for sending someone to a specific cleanup feature from an ad even if they don't have the app yet. Implementation-wise, the destination is resolved from the URI path and validated to avoid opening untrusted parameters.