AASA-Universal-Links-Information

All interesting hidden and not information about iOS deeplinks (universal links).

Apple documentation:

Test links:

To see AASA file on apple CDN: https://app-site-association.cdn-apple.com/a/v1/YOURDOMAIN

To see AASA file on your site: https://YOURDOMAINcom/.well-known/apple-app-site-association

Developer mode:

https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_developer_associated-domains
In macOS 11 and later and iOS 14 and later, apps request apple-app-site-association files from an Apple-managed content delivery network (CDN) specifically for associated domains, instead of directly from your web server. If the CDN has an old version of the file, or doesn’t already have a copy of the file, it connects to your web server to obtain the latest version.

About refreshing AASA file on apple CDN: https://developer.apple.com/forums/thread/699401

CDN will cache approximely once a day new AASA file.
If you trigger a sysdiagnose, in the swcutil_show.txt file you can look for your domain and find information about when the "last check" was, and when the next check will be.
If you are iterating at a fast pace, you can use developer mode, and directly pull the AASA from your web server.
To trigger a download you still need to delete the app and reinstall via Xcode (TF and App Store do not work for developer mode.)

To enable Developer mode:

1)applinks:mydomain.com?mode=developer in entitlements. 2) Enable setting on your device. Xcode -> Signing and.. -> Associated Domains Development.

NOT word:

Nice question and answer https://stackoverflow.com/q/58217784/5790492

Various

https://stackoverflow.com/a/44685218/5790492
You are correct that the apple-app-site-association file is downloaded when the app is installed. It will be re-downloaded for updates through the App Store, which means to add new paths and ensure all users have them, you generally need to release an app update.

Often Errors

Check that your AASA file is valid:

Use new apple format. "/": "". "components" instead "path" and so on;
Validate JSON. It can be that you forget to remove comma or quotation mark;
Check the "apps": [] exists;
Check that apple cashed your new version on CDN. Otherwise use developer mode;
Reinstall app or update it. AASA downloaded this time;
Be sure that your backend developer did everything well. Check local file. Check that your domain of ULink has it.

In my case was a problem that app opened everything with domain from assocatedDomains as a deeplink.

Examples from big services

JSON and AASA Validators

Example

Here is the example of AASA file where root links not opens. This is new format of AASA. With old format file didn't work and didn't refirect me.

{
    "applinks": {
        "apps": [

        ],
        "details": [{
            "appIDs": [
                "XXXXXXXXXX.com.bundleId",
                "YYYYYYYYYY.com.bundleId"
            ],
            "components": [
                {
                    "/": "/test/*"
                },
                {
                    "/": "/*/type/criteria/*"
                },
                {
                    "/": "/*/news/*"
                },
                {
                    "/": "/*/some/details/*"
                },
                {
                    "/": "/*/sales/*/view/*"
                },
                {
                    "/": "/*",
                    "exclude": true
                }
            ]
        }]
    }
}

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All interesting hidden and not information about iOS deeplinks (universal links).