Capsule for Android

Send and receive files privately, straight from your Android device

Screenshots

Features

• Upload files directly or via the system share sheet
• Download files by ID or QR code scan
• Optional client-side end-to-end encryption with a BIP39 mnemonic passphrase
• QR code display after upload for easy sharing
• Upload history with time remaining per file
• Self-hosted server support, including LAN
• Dark, light, and system theme
• Anonymous opt-out analytics

Building

./gradlew installDebug      # build and install on a connected device/emulator

Testing

Everyday runs use the debug build type, so unit and instrumented tests are runnable straight from Android Studio's gutter icons:

./gradlew testDebugUnitTest         # JVM unit tests (fast, no device)
./gradlew connectedDebugAndroidTest # instrumented tests on a connected device/emulator

Release-crash guard (R8)

To catch "works in debug, crashes in release" regressions, such as stripped serializers, missing keep rules, etc., run the instrumented tests against the minified build by passing -PtestR8:

./gradlew connectedReleaseTestAndroidTest -PtestR8

-PtestR8 retargets testBuildType at the releaseTest build type, which mirrors the shipping release build exactly (same R8 minification, resource shrinking, and proguard-rules.pro) so the tests exercise minified/obfuscated code. It layers on only test-runner keep rules (release-test-keep.pro for the app side, androidTest-rules.pro for the test APK) and never affects the shipping release APK. This is the check worth running in CI before a release.

Note: AGP generates the test components only for the active testBuildType, so with -PtestR8 the task names shift to testReleaseTestUnitTest / connectedReleaseTestAndroidTest. Without the flag (the default), Android Studio sees the debug components and gutter icons work normally.

Documentation

Full documentation lives at docs.withcapsule.dev.

See PRIVACY_POLICY.md for how the app handles data.