Deep linking
What is the apple-app-site-association file?
Short answer
The apple-app-site-association (AASA) file is a JSON file on your domain that tells iOS which apps may open which links there. It lives at /.well-known/apple-app-site-association, must be served over HTTPS without redirects, and lists each app by its Team ID and bundle ID together with the paths it handles.
What goes inside
An applinks section with one entry per app. Each entry names the app ID, which is your Apple Team ID and the bundle ID joined by a dot, plus the paths or URL components the app should open. Anything the file doesn’t list stays on the website. The file name has no .json extension, even though the content is JSON.
How Apple reads it
iPhones don’t download the file from your server every time a link is tapped. Apple’s CDN fetches it when the app is installed or updated, and devices get it from there.
Two things follow. A fix on your server may take a while to show up on phones. And a file that redirects, or returns an error page instead of JSON, never arrives at all, so the links open the website.
https://example.com/.well-known/apple-app-site-associationRelated terms
- Universal Links
Universal Links are Apple’s https links that open an installed iOS app directly instead of the website, available since iOS 9. They need the Associated Domains entitlement in the app, such as applinks:example.com, and an apple-app-site-association file on the domain. Without the app, the same link simply opens the website.
- assetlinks.json
assetlinks.json is the Digital Asset Links file that proves to Android your domain trusts your app, so verified App Links open the app directly. It sits at /.well-known/assetlinks.json, is served over HTTPS as JSON without redirects, and lists your package name with the SHA-256 fingerprints of your signing certificates.
One link for every phone
Create a free smart link and QR code that sends iPhones to the App Store, Android phones to Google Play and desktops to your website.