Free Android developer tools

App Links connect three things that have to match exactly: the assetlinks.json file on your domain, the intent filters in your manifest, and the SHA-256 fingerprint of the certificate that signs the installed app. The assetlinks.json generator and validator builds the file from your package name and fingerprints, checks a file you already publish, and asks Google's Digital Asset Links API what it reads from your domain.

The keystore and APK fingerprint tool reads the certificates in a JKS or PKCS#12 keystore, an APK or an app bundle and shows their SHA-1 and SHA-256 fingerprints, so you can see which key signed a build. With Play App Signing, the fingerprint Google needs is the app signing key's from Play Console, not your upload key's, and the tool says so.

The deep link tester builds the adb, intent:// and iOS Simulator commands for a link with the shell quoting done for you, makes a QR code to scan on a phone, and checks whether an intent filter or an apple-app-site-association file matches the link.

The adaptive icon generator makes the foreground, background and monochrome layers that Android 8 and later launchers use, the anydpi-v26 XML that ties them together and the 512 px Play Store icon, with a safe-zone overlay and previews of launcher masks and themed icons.

For the iOS side of the same jobs, the developer tools page has the AASA validator for Universal Links, the push notification tester and the app icon generator for Xcode asset catalogs.