FTW app

Your home's energy, on the phone.

Native iOS (SwiftUI) and Android (Jetpack Compose). Shared logic is Kotlin Multiplatform: pairing, passkeys, Noise, the relay, the session. The box at home is the record. This app is a cached projection of it. The cloud is blind.

Not a wrap of the web app. Same protocol, same QR, same relay, same RP ID (app.ftw.energy).

Shape

SwiftUI / Compose
        │
        ▼
   shared (KMP)  — enrollment, vault, Noise IK, frames, session, relay
        │
        ▼
  wss://relay.ftw.energy   (encrypted)
        │
        ▼
     FTW box

Two taps: scan the QR on the box, Face ID / biometrics, the house.

Status (2026-08-22)

V1 is Pair + Now. That is on main as of 2026-08-22. Not a wrap of the web app. Not Flutter, not React Native.

In the apps today

• Scan or paste a v2 pairing QR (https://app.ftw.energy/p#v2.…).
• One passkey prompt at enroll. RP ID app.ftw.energy. PRF salt ftw.prf.v1.vault.
• Noise_IK_25519_ChaChaPoly_SHA256 to the box through wss://relay.ftw.energy.
• Now shows headline plus grid / solar / battery / house from frozen field ids.
• Vault, site and last readings live in iOS Keychain / Android EncryptedSharedPreferences. Cold start paints from cache, then reconnects without Face ID. Forget wipes the store.

Proven here

Check	Result
./gradlew :shared:jvmTest	Green
Live box e2e (127.0.0.1:18080 + production relay)	hello_ok + snapshot, phase streaming
iOS Simulator (iPhone 17, iOS 26.5)	Built and launched
Android emulator FTW_Phone (API 35 ARM64)	APK installed, Pair shown twice

Passkey PRF cannot run on the JVM. Live e2e uses a local wrapping key for the ceremony and the real Noise / relay / box path. The Android emulator has no camera feed — paste the pairing link.

Not v1 (do not start these next)

Energy, History, Plan, EV, commands, escrow restore, spoken codes, LAN, WebRTC, push, App Store / Play listing.

Known holes

• srcState should follow the Now fields' srcId in the dict, not every driver on the site.
• Wrap key is raw PRF bytes, not the web app's HKDF. A native vault will not open in the PWA, and the other way around.
• PasskeyHost.enroll from Kotlin still blocks. The UIs call the async ceremony and skip that path.
• Field ids in Explanation.kt are still hand-written; they should come from protocol/registry.yaml.

Tests

JDK 21.

export JAVA_HOME="$(brew --prefix openjdk@21)/libexec/openjdk.jdk/Contents/Home"
./gradlew :shared:jvmTest

That suite covers enrollment URLs, Cacophony Noise IK, hello/sub CBOR matching the box's interop hex, 512-byte lane 0 frames, the vault, and a session that turns hello_ok + snap into Now state.

E2E against FTW

Start a box (make dev in srcfl/ftw, or go run ./cmd/ftw with app_link.enabled: true). The box joins wss://relay.ftw.energy — that origin is fixed on the box, so the client meets it there.

export FTW_LIVE_BOX=127.0.0.1:8080   # or 18080 if the API port moved
export FTW_LIVE_RELAY=wss://relay.ftw.energy
./scripts/e2e-ftw.sh

The test mints POST /api/app-link/pairing with {"role":"owner"}, runs the shipped connectToSite path (Noise IK, pairing code in handshake message 1, prologue ftw.session.v1: + box static), and asserts hello_ok plus a snapshot that includes the frozen field ids.

Native apps

iOS: open iosApp/iosApp.xcodeproj. SwiftUI Pair (camera QR + paste) and Now. Xcode 16+, iOS 18 for passkey PRF. A Run Script build phase compiles the Shared framework with ./gradlew :shared:embedAndSignAppleFrameworkForXcode.

Android: ./gradlew :androidApp:assembleDebug (minSdk 28). Pair uses CameraX

• ML Kit for the QR. Passkeys go through Credential Manager.

Emulator (AVD FTW_Phone, API 35 ARM64 Google APIs):

export ANDROID_HOME="$HOME/Android/sdk"
"$ANDROID_HOME/emulator/emulator" -avd FTW_Phone
adb install -r androidApp/build/outputs/apk/debug/androidApp-debug.apk
adb shell am start -n energy.ftw.app/.MainActivity

RP ID app.ftw.energy. PRF salt ftw.prf.v1.vault. Reading uses a local wrapping copy so Now paints without a passkey prompt.

Layout

Path	What
shared/	KMP: identity, crypto, protocol, relay, session
androidApp/	Compose UI
iosApp/	SwiftUI UI
protocol/registry.yaml	Names shared with the box
scripts/e2e-ftw.sh	Live box e2e

Licence

Apache-2.0. See LICENSE.