feat(android): QR pairing — scan, deep link, one-step auto-login

Companion side of docs/companion-pairing-qr.md (v1 contract):
- Connect screen lands on Scan Node's QR / Enter Manually; NESMenu gains
  an add-server-by-QR icon button
- QrScannerOverlay: CameraX + ZXing core (pinned, on-device, no ML Kit)
- ServerQrParser: archipelago://pair?v=1&url=..[&pw=..]; unknown major v
  -> 'update the app'; upsert by origin so re-scans never duplicate
- archipelago:// deep link registered (singleTask + onNewIntent) for the
  modal's 'Open in companion app' button
- WebView auto-fills and submits Login.vue's password form when a stored
  password exists — demo QR is one step to a logged-in session
- Web modal + handoff doc copy synced to the real label: Scan Node's QR
- v0.4.13 (versionCode 17)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Android/app/build.gradle.kts

@@ -11,8 +11,8 @@ android {
         applicationId = "com.archipelago.app"
         minSdk = 26
         targetSdk = 35
-        versionCode = 16
-        versionName = "0.4.12"
+        versionCode = 17
+        versionName = "0.4.13"
 
         vectorDrawables {
             useSupportLibrary = true
@@ -111,6 +111,12 @@ dependencies {
     // OkHttp for WebSocket (remote input)
     implementation("com.squareup.okhttp3:okhttp:4.12.0")
 
+    // CameraX + ZXing (Apache-2.0, on-device, no telemetry) for pairing-QR scanning
+    implementation("androidx.camera:camera-camera2:1.3.4")
+    implementation("androidx.camera:camera-lifecycle:1.3.4")
+    implementation("androidx.camera:camera-view:1.3.4")
+    implementation("com.google.zxing:core:3.5.3")
+
     debugImplementation("androidx.compose.ui:ui-tooling")
     debugImplementation("androidx.compose.ui:ui-test-manifest")
 }

Android/app/src/main/AndroidManifest.xml

@@ -4,6 +4,9 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <!-- Pairing-QR scanner. Camera is optional: manual entry still works without one. -->
+    <uses-permission android:name="android.permission.CAMERA" />
+    <uses-feature android:name="android.hardware.camera.any" android:required="false" />
 
     <application
         android:name=".ArchipelagoApp"
@@ -19,6 +22,7 @@
         <activity
             android:name=".MainActivity"
             android:exported="true"
+            android:launchMode="singleTask"
             android:theme="@style/Theme.Archipelago.Splash"
             android:windowSoftInputMode="adjustResize"
             android:configChanges="orientation|screenSize|screenLayout|keyboardHidden">
@@ -26,6 +30,14 @@
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <!-- Pairing deep link from the web UI's Companion popup:
+                 archipelago://pair?v=1&url=...[&pw=...] (docs/companion-pairing-qr.md) -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="archipelago" android:host="pair" />
+            </intent-filter>
         </activity>
     </application>
 

Android/app/src/main/java/com/archipelago/app/MainActivity.kt

@@ -1,22 +1,41 @@
 package com.archipelago.app
 
+import android.content.Intent
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
 import com.archipelago.app.ui.navigation.AppNavHost
 import com.archipelago.app.ui.theme.ArchipelagoTheme
+import kotlinx.coroutines.flow.MutableStateFlow
 
 class MainActivity : ComponentActivity() {
+
+    // Pairing deep link (archipelago://pair?...) from the launch intent or a
+    // later one (launchMode=singleTask). Consumed by AppNavHost.
+    private val pendingPairUri = MutableStateFlow<String?>(null)
+
     override fun onCreate(savedInstanceState: Bundle?) {
         installSplashScreen()
         enableEdgeToEdge()
         super.onCreate(savedInstanceState)
+        pendingPairUri.value = intent?.dataString
         setContent {
             ArchipelagoTheme {
-                AppNavHost()
+                val pairUri by pendingPairUri.collectAsState()
+                AppNavHost(
+                    pairUri = pairUri,
+                    onPairUriConsumed = { pendingPairUri.value = null },
+                )
             }
         }
     }
+
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        pendingPairUri.value = intent.dataString
+    }
 }

Android/app/src/main/java/com/archipelago/app/data/ServerPreferences.kt

@@ -143,6 +143,39 @@ class ServerPreferences(private val context: Context) {
         }
     }
 
+    /**
+     * Add a server, or update the entry with the same connection identity
+     * (address/port/scheme) — used by QR pairing so re-scanning a node never
+     * duplicates it. A blank incoming password/name keeps the stored value
+     * (a real node's QR never carries the password). Returns the merged entry.
+     */
+    suspend fun upsertServer(server: ServerEntry): ServerEntry {
+        var merged = server
+        context.dataStore.edit { prefs ->
+            val current = prefs[savedServersKey] ?: emptySet()
+            val existing = current.mapNotNull { ServerEntry.deserialize(it) }.firstOrNull {
+                it.address == server.address &&
+                    it.port == server.port &&
+                    it.useHttps == server.useHttps
+            }
+            if (existing != null) {
+                merged = server.copy(
+                    password = server.password.ifBlank { existing.password },
+                    name = server.name.ifBlank { existing.name },
+                )
+            }
+            val filtered = current.filterNot { raw ->
+                val e = ServerEntry.deserialize(raw)
+                e != null &&
+                    e.address == server.address &&
+                    e.port == server.port &&
+                    e.useHttps == server.useHttps
+            }.toSet()
+            prefs[savedServersKey] = filtered + merged.serialize()
+        }
+        return merged
+    }
+
     suspend fun removeSavedServer(server: ServerEntry) {
         context.dataStore.edit { prefs ->
             val current = prefs[savedServersKey] ?: emptySet()

Android/app/src/main/java/com/archipelago/app/data/ServerQrParser.kt

@@ -0,0 +1,67 @@
+package com.archipelago.app.data
+
+import android.net.Uri
+
+/**
+ * Result of parsing a pairing QR / deep link.
+ *
+ * UnsupportedVersion means the payload is structurally a pairing URI but its
+ * major version is newer than this app understands — the UI should tell the
+ * user to update the app rather than call the code invalid.
+ */
+sealed class PairResult {
+    data class Success(val server: ServerEntry) : PairResult()
+    object UnsupportedVersion : PairResult()
+    object Invalid : PairResult()
+}
+
+/**
+ * Parser for the companion pairing QR / OS deep link. Contract:
+ * docs/companion-pairing-qr.md (repo root).
+ *
+ *   archipelago://pair?v=1&url=<percent-encoded origin>[&pw=<password>]
+ *
+ * - `url` is a full origin including scheme (http for LAN/mDNS nodes, https
+ *   for the public demo); trailing slashes are normalized away.
+ * - `pw` is only ever present for the public demo.
+ * - Unknown extra query params are tolerated (forward compat under v=1 —
+ *   `name` is already honored if present).
+ */
+object ServerQrParser {
+    private const val SUPPORTED_MAJOR = 1
+
+    fun parse(raw: String): PairResult {
+        val uri = try {
+            Uri.parse(raw.trim())
+        } catch (_: Exception) {
+            return PairResult.Invalid
+        }
+        if (!"archipelago".equals(uri.scheme, ignoreCase = true)) return PairResult.Invalid
+        if (uri.isOpaque || !"pair".equals(uri.host, ignoreCase = true)) return PairResult.Invalid
+
+        val major = uri.getQueryParameter("v")
+            ?.trim()
+            ?.takeWhile { it.isDigit() }
+            ?.toIntOrNull()
+            ?: return PairResult.Invalid
+        if (major != SUPPORTED_MAJOR) return PairResult.UnsupportedVersion
+
+        val serverUrl = uri.getQueryParameter("url")?.trim()?.trimEnd('/')
+        if (serverUrl.isNullOrBlank()) return PairResult.Invalid
+        val server = Uri.parse(serverUrl)
+        val scheme = server.scheme?.lowercase()
+        if (scheme != "http" && scheme != "https") return PairResult.Invalid
+        val host = server.host
+        if (host.isNullOrBlank()) return PairResult.Invalid
+
+        return PairResult.Success(
+            ServerEntry(
+                address = host,
+                useHttps = scheme == "https",
+                port = if (server.port != -1) server.port.toString() else "",
+                password = uri.getQueryParameter("pw") ?: "",
+                name = uri.getQueryParameter("name") ?: "",
+            )
+        )
+    }
+}

Android/app/src/main/java/com/archipelago/app/ui/components/NESMenu.kt

@@ -24,6 +24,9 @@ import androidx.compose.foundation.layout.widthIn
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.text.KeyboardActions
 import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.QrCodeScanner
+import androidx.compose.material3.Icon
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.OutlinedTextFieldDefaults
 import androidx.compose.material3.Text
@@ -36,6 +39,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.ImeAction
@@ -44,6 +48,7 @@ import androidx.compose.ui.text.input.PasswordVisualTransformation
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import com.archipelago.app.R
 import com.archipelago.app.data.ServerEntry
 import com.archipelago.app.ui.theme.BitcoinOrange
 import com.archipelago.app.ui.theme.ControllerStyle
@@ -75,6 +80,7 @@ fun NESMenu(
     onDismiss: () -> Unit,
     onSelectServer: (ServerEntry) -> Unit,
     onAddServer: (ServerEntry) -> Unit,
+    onScanQr: (() -> Unit)? = null,
     onEditServer: (ServerEntry, ServerEntry) -> Unit,
     onRemoveServer: (ServerEntry) -> Unit,
     onToggleMode: () -> Unit,
@@ -88,7 +94,7 @@ fun NESMenu(
             contentAlignment = Alignment.Center,
         ) {
             AnimatedVisibility(visible = visible, enter = fadeIn() + scaleIn(initialScale = 0.95f), exit = fadeOut() + scaleOut(targetScale = 0.95f)) {
-                MenuPanel(servers, activeServer, isGamepadMode, controllerStyle, onDismiss, onSelectServer, onAddServer, onEditServer, onRemoveServer, onToggleMode, onToggleStyle, onBackToWebView)
+                MenuPanel(servers, activeServer, isGamepadMode, controllerStyle, onDismiss, onSelectServer, onAddServer, onScanQr, onEditServer, onRemoveServer, onToggleMode, onToggleStyle, onBackToWebView)
             }
         }
     }
@@ -103,6 +109,7 @@ private fun MenuPanel(
     onDismiss: () -> Unit,
     onSelectServer: (ServerEntry) -> Unit,
     onAddServer: (ServerEntry) -> Unit,
+    onScanQr: (() -> Unit)?,
     onEditServer: (ServerEntry, ServerEntry) -> Unit,
     onRemoveServer: (ServerEntry) -> Unit,
     onToggleMode: () -> Unit,
@@ -235,7 +242,30 @@ private fun MenuPanel(
                 }
             }
         } else {
-            MenuItem(label = "Add Server", labelColor = BitcoinOrange, onClick = { showAdd = true })
+            Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                Box(Modifier.weight(1f)) {
+                    MenuItem(label = "Add Server", labelColor = BitcoinOrange, onClick = { showAdd = true })
+                }
+                if (onScanQr != null) {
+                    // Add server by scanning the node's pairing QR
+                    Box(
+                        Modifier
+                            .size(ROW_H)
+                            .clip(RoundedCornerShape(ROW_R))
+                            .background(RowBg)
+                            .border(1.dp, RowBorder, RoundedCornerShape(ROW_R))
+                            .clickable { onScanQr() },
+                        contentAlignment = Alignment.Center,
+                    ) {
+                        Icon(
+                            Icons.Default.QrCodeScanner,
+                            contentDescription = stringResource(R.string.add_server_qr),
+                            tint = BitcoinOrange,
+                            modifier = Modifier.size(24.dp),
+                        )
+                    }
+                }
+            }
         }
 
         Spacer(Modifier.height(2.dp))

Android/app/src/main/java/com/archipelago/app/ui/components/QrScannerOverlay.kt

@@ -0,0 +1,298 @@
+package com.archipelago.app.ui.components
+
+import android.Manifest
+import android.content.pm.PackageManager
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.camera.core.CameraSelector
+import androidx.camera.core.ImageAnalysis
+import androidx.camera.core.ImageProxy
+import androidx.camera.core.Preview
+import androidx.camera.lifecycle.ProcessCameraProvider
+import androidx.camera.view.PreviewView
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.safeDrawing
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.windowInsetsPadding
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalLifecycleOwner
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.viewinterop.AndroidView
+import androidx.core.content.ContextCompat
+import com.archipelago.app.R
+import com.archipelago.app.data.PairResult
+import com.archipelago.app.data.ServerEntry
+import com.archipelago.app.data.ServerQrParser
+import com.archipelago.app.ui.screens.GlassButton
+import com.archipelago.app.ui.theme.BitcoinOrange
+import com.archipelago.app.ui.theme.TextMuted
+import com.archipelago.app.ui.theme.TextPrimary
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.BinaryBitmap
+import com.google.zxing.DecodeHintType
+import com.google.zxing.MultiFormatReader
+import com.google.zxing.NotFoundException
+import com.google.zxing.PlanarYUVLuminanceSource
+import com.google.zxing.common.HybridBinarizer
+import kotlinx.coroutines.delay
+import java.util.concurrent.Executors
+
+/**
+ * Full-screen camera overlay that scans the node pairing QR
+ * (docs/companion-pairing-qr.md) and reports the decoded server entry.
+ * Handles the camera permission itself; foreign/invalid codes show a hint
+ * and scanning continues.
+ */
+@Composable
+fun QrScannerOverlay(
+    visible: Boolean,
+    onDismiss: () -> Unit,
+    onServerScanned: (ServerEntry) -> Unit,
+) {
+    val context = LocalContext.current
+    var hasPermission by remember {
+        mutableStateOf(
+            ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA) ==
+                PackageManager.PERMISSION_GRANTED
+        )
+    }
+    var hintRes by remember { mutableStateOf<Int?>(null) }
+    var handled by remember { mutableStateOf(false) }
+
+    val permissionLauncher = rememberLauncherForActivityResult(
+        ActivityResultContracts.RequestPermission()
+    ) { granted -> hasPermission = granted }
+
+    LaunchedEffect(visible) {
+        if (visible) {
+            handled = false
+            hintRes = null
+            val granted = ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA) ==
+                PackageManager.PERMISSION_GRANTED
+            hasPermission = granted
+            if (!granted) permissionLauncher.launch(Manifest.permission.CAMERA)
+        }
+    }
+
+    // Foreign-code hint fades after a moment so scanning feels live again.
+    LaunchedEffect(hintRes) {
+        if (hintRes != null) {
+            delay(2500)
+            hintRes = null
+        }
+    }
+
+    AnimatedVisibility(visible = visible, enter = fadeIn(), exit = fadeOut()) {
+        BackHandler { onDismiss() }
+        Box(
+            Modifier
+                .fillMaxSize()
+                .background(Color.Black),
+        ) {
+            if (hasPermission) {
+                CameraQrPreview(
+                    onDecoded = { text ->
+                        if (!handled) {
+                            when (val result = ServerQrParser.parse(text)) {
+                                is PairResult.Success -> {
+                                    handled = true
+                                    onServerScanned(result.server)
+                                }
+                                is PairResult.UnsupportedVersion -> hintRes = R.string.update_app_for_qr
+                                is PairResult.Invalid -> hintRes = R.string.invalid_pairing_qr
+                            }
+                        }
+                    },
+                )
+                // Aim frame
+                Box(
+                    Modifier
+                        .align(Alignment.Center)
+                        .size(260.dp)
+                        .border(2.dp, BitcoinOrange.copy(alpha = 0.85f), RoundedCornerShape(20.dp)),
+                )
+            } else {
+                Column(
+                    Modifier
+                        .align(Alignment.Center)
+                        .padding(horizontal = 32.dp),
+                    horizontalAlignment = Alignment.CenterHorizontally,
+                    verticalArrangement = Arrangement.spacedBy(16.dp),
+                ) {
+                    Text(
+                        text = stringResource(R.string.camera_permission_needed),
+                        color = TextPrimary,
+                        style = MaterialTheme.typography.bodyLarge,
+                        textAlign = TextAlign.Center,
+                    )
+                    GlassButton(
+                        text = stringResource(R.string.grant_camera_access),
+                        onClick = { permissionLauncher.launch(Manifest.permission.CAMERA) },
+                        modifier = Modifier.fillMaxWidth().height(56.dp),
+                    )
+                }
+            }
+
+            // Top bar: title + close
+            Row(
+                Modifier
+                    .fillMaxWidth()
+                    .windowInsetsPadding(WindowInsets.safeDrawing)
+                    .padding(horizontal = 8.dp, vertical = 4.dp),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.SpaceBetween,
+            ) {
+                Text(
+                    text = stringResource(R.string.scan_node_qr),
+                    color = TextPrimary,
+                    style = MaterialTheme.typography.titleMedium,
+                    modifier = Modifier.padding(start = 12.dp),
+                )
+                IconButton(onClick = onDismiss) {
+                    Icon(Icons.Default.Close, stringResource(R.string.close), tint = TextPrimary)
+                }
+            }
+
+            // Bottom hints
+            Column(
+                Modifier
+                    .align(Alignment.BottomCenter)
+                    .windowInsetsPadding(WindowInsets.safeDrawing)
+                    .padding(horizontal = 32.dp, vertical = 24.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+            ) {
+                hintRes?.let { res ->
+                    Text(
+                        text = stringResource(res),
+                        color = BitcoinOrange,
+                        style = MaterialTheme.typography.bodyMedium,
+                        textAlign = TextAlign.Center,
+                    )
+                    Spacer(Modifier.height(8.dp))
+                }
+                if (hasPermission) {
+                    Text(
+                        text = stringResource(R.string.scan_qr_hint),
+                        color = TextMuted,
+                        style = MaterialTheme.typography.bodyMedium,
+                        textAlign = TextAlign.Center,
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun CameraQrPreview(onDecoded: (String) -> Unit) {
+    val context = LocalContext.current
+    val lifecycleOwner = LocalLifecycleOwner.current
+    val currentOnDecoded by rememberUpdatedState(onDecoded)
+    val previewView = remember {
+        PreviewView(context).apply { scaleType = PreviewView.ScaleType.FILL_CENTER }
+    }
+
+    DisposableEffect(Unit) {
+        val analysisExecutor = Executors.newSingleThreadExecutor()
+        val mainExecutor = ContextCompat.getMainExecutor(context)
+        val providerFuture = ProcessCameraProvider.getInstance(context)
+        var provider: ProcessCameraProvider? = null
+
+        providerFuture.addListener({
+            val p = providerFuture.get()
+            provider = p
+            val preview = Preview.Builder().build().also {
+                it.setSurfaceProvider(previewView.surfaceProvider)
+            }
+            val analysis = ImageAnalysis.Builder()
+                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
+                .build()
+                .also {
+                    it.setAnalyzer(
+                        analysisExecutor,
+                        QrCodeAnalyzer { text -> mainExecutor.execute { currentOnDecoded(text) } },
+                    )
+                }
+            try {
+                p.unbindAll()
+                p.bindToLifecycle(lifecycleOwner, CameraSelector.DEFAULT_BACK_CAMERA, preview, analysis)
+            } catch (_: Exception) {
+                // Camera unavailable — the user can dismiss and enter details manually.
+            }
+        }, mainExecutor)
+
+        onDispose {
+            provider?.unbindAll()
+            analysisExecutor.shutdown()
+        }
+    }
+
+    AndroidView(factory = { previewView }, modifier = Modifier.fillMaxSize())
+}
+
+/** ZXing-based QR decoder over the camera's Y (luminance) plane. */
+private class QrCodeAnalyzer(private val onDecoded: (String) -> Unit) : ImageAnalysis.Analyzer {
+    private val reader = MultiFormatReader().apply {
+        setHints(mapOf(DecodeHintType.POSSIBLE_FORMATS to listOf(BarcodeFormat.QR_CODE)))
+    }
+
+    override fun analyze(image: ImageProxy) {
+        try {
+            val plane = image.planes[0]
+            val buffer = plane.buffer
+            // Copy into a rowStride-wide array; the last row of the plane buffer
+            // may be short of the full stride, so the tail stays zero-padded.
+            val data = ByteArray(plane.rowStride * image.height)
+            buffer.get(data, 0, minOf(buffer.remaining(), data.size))
+            val source = PlanarYUVLuminanceSource(
+                data, plane.rowStride, image.height,
+                0, 0, image.width, image.height,
+                false,
+            )
+            val result = reader.decodeWithState(BinaryBitmap(HybridBinarizer(source)))
+            onDecoded(result.text)
+        } catch (_: NotFoundException) {
+            // No QR in this frame — keep scanning.
+        } catch (_: Exception) {
+            // Malformed frame; skip it.
+        } finally {
+            reader.reset()
+            image.close()
+        }
+    }
+}

Android/app/src/main/java/com/archipelago/app/ui/navigation/NavGraph.kt

@@ -1,15 +1,21 @@
 package com.archipelago.app.ui.navigation
 
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.platform.LocalContext
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
+import com.archipelago.app.data.PairResult
+import com.archipelago.app.data.ServerEntry
 import com.archipelago.app.data.ServerPreferences
+import com.archipelago.app.data.ServerQrParser
 import com.archipelago.app.ui.screens.IntroScreen
 import com.archipelago.app.ui.screens.RemoteInputScreen
 import com.archipelago.app.ui.screens.ServerConnectScreen
@@ -24,7 +30,10 @@ object Routes {
 }
 
 @Composable
-fun AppNavHost() {
+fun AppNavHost(
+    pairUri: String? = null,
+    onPairUriConsumed: () -> Unit = {},
+) {
     val context = LocalContext.current
     val prefs = remember { ServerPreferences(context) }
     val navController = rememberNavController()
@@ -33,8 +42,41 @@ fun AppNavHost() {
     val introSeen by prefs.introSeen.collectAsState(initial = null)
     val activeServer by prefs.activeServer.collectAsState(initial = null)
 
+    // Pairing entry from a deep link that carried no password — prefills the
+    // connect form so the user lands on the password prompt for that server.
+    var pairPrefill by remember { mutableStateOf<ServerEntry?>(null) }
+
     if (introSeen == null) return
 
+    // Declared after the introSeen gate so it can't fire before the NavHost
+    // below has set the nav graph; pairUri stays pending until consumed here.
+    LaunchedEffect(pairUri) {
+        val raw = pairUri ?: return@LaunchedEffect
+        onPairUriConsumed()
+        when (val result = ServerQrParser.parse(raw)) {
+            is PairResult.Success -> {
+                // Pairing implies the app is installed and in use — skip the intro.
+                prefs.markIntroSeen()
+                val merged = prefs.upsertServer(result.server)
+                if (merged.password.isNotBlank()) {
+                    // Demo flow: password came with the link — connect in one step.
+                    prefs.setActiveServer(merged)
+                    navController.navigate(Routes.WEB_VIEW) {
+                        popUpTo(0) { inclusive = true }
+                    }
+                } else {
+                    pairPrefill = merged
+                    navController.navigate(Routes.SERVER_CONNECT) {
+                        popUpTo(0) { inclusive = true }
+                    }
+                }
+            }
+            else -> {
+                // Invalid or too-new pairing link — ignore; normal startup continues.
+            }
+        }
+    }
+
     val startDestination = when {
         introSeen == false -> Routes.INTRO
         activeServer != null -> Routes.WEB_VIEW
@@ -65,6 +107,7 @@ fun AppNavHost() {
                         popUpTo(Routes.SERVER_CONNECT) { inclusive = true }
                     }
                 },
+                initialServer = pairPrefill,
             )
         }
 
@@ -81,6 +124,7 @@ fun AppNavHost() {
             } else {
                 WebViewScreen(
                     serverUrl = server.toUrl(),
+                    serverPassword = server.password,
                     onDisconnect = {
                         scope.launch {
                             prefs.clearActiveServer()

Android/app/src/main/java/com/archipelago/app/ui/screens/RemoteInputScreen.kt

@@ -43,6 +43,7 @@ import com.archipelago.app.ui.components.NESController
 import com.archipelago.app.ui.components.NESKeyboard
 import com.archipelago.app.ui.components.NESMenu
 import com.archipelago.app.ui.components.NESPortraitController
+import com.archipelago.app.ui.components.QrScannerOverlay
 import com.archipelago.app.ui.components.Trackpad
 import com.archipelago.app.ui.theme.BitcoinOrange
 import com.archipelago.app.ui.theme.ControllerStyle
@@ -63,6 +64,7 @@ fun RemoteInputScreen(onBack: () -> Unit) {
 
     var isGamepadMode by remember { mutableStateOf(true) }
     var showModal by remember { mutableStateOf(false) }
+    var showQrScanner by remember { mutableStateOf(false) }
     var controllerStyle by remember { mutableStateOf(ControllerStyle.DARK) }
     var playerId by remember { mutableStateOf(0) }  // 0 = broadcast, 1 = P1, 2 = P2
 
@@ -216,6 +218,7 @@ fun RemoteInputScreen(onBack: () -> Unit) {
             onAddServer = { server ->
                 scope.launch { prefs.addSavedServer(server); if (activeServer == null) prefs.setActiveServer(server) }
             },
+            onScanQr = { showQrScanner = true },
             onEditServer = { original, updated ->
                 scope.launch {
                     prefs.updateSavedServer(original, updated)
@@ -247,5 +250,19 @@ fun RemoteInputScreen(onBack: () -> Unit) {
             },
             onBackToWebView = { showModal = false; onBack() },
         )
+
+        // Pairing-QR scan launched from the menu's Add Server row. The menu stays
+        // open behind the scanner so the new entry appears as soon as it closes.
+        QrScannerOverlay(
+            visible = showQrScanner,
+            onDismiss = { showQrScanner = false },
+            onServerScanned = { server ->
+                showQrScanner = false
+                scope.launch {
+                    val merged = prefs.upsertServer(server)
+                    if (activeServer == null) prefs.setActiveServer(merged)
+                }
+            },
+        )
     }
 }

Android/app/src/main/java/com/archipelago/app/ui/screens/ServerConnectScreen.kt

@@ -43,6 +43,7 @@ import androidx.compose.material3.Switch
 import androidx.compose.material3.SwitchDefaults
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -72,6 +73,7 @@ import androidx.compose.ui.unit.sp
 import com.archipelago.app.R
 import com.archipelago.app.data.ServerEntry
 import com.archipelago.app.data.ServerPreferences
+import com.archipelago.app.ui.components.QrScannerOverlay
 import com.archipelago.app.ui.theme.BitcoinOrange
 import com.archipelago.app.ui.theme.ErrorRed
 import com.archipelago.app.ui.theme.SurfaceBlack
@@ -93,6 +95,9 @@ import javax.net.ssl.X509TrustManager
 fun ServerConnectScreen(
     onConnected: (String) -> Unit,
     onRemoteInput: () -> Unit = {},
+    // Prefill from a pairing deep link (archipelago://pair) that carried no
+    // password — opens the manual form on the password prompt for that server.
+    initialServer: ServerEntry? = null,
 ) {
     val context = LocalContext.current
     val prefs = remember { ServerPreferences(context) }
@@ -109,6 +114,9 @@ fun ServerConnectScreen(
     var errorMessage by remember { mutableStateOf<String?>(null) }
     // The saved server currently being edited, or null when adding/connecting.
     var editingServer by remember { mutableStateOf<ServerEntry?>(null) }
+    // Landing shows Scan/Manual choice; the form appears in manual mode or while editing.
+    var manualMode by remember { mutableStateOf(false) }
+    var showScanner by remember { mutableStateOf(false) }
 
     val savedServers by prefs.savedServers.collectAsState(initial = emptyList())
 
@@ -173,6 +181,37 @@ fun ServerConnectScreen(
         }
     }
 
+    fun prefill(server: ServerEntry) {
+        name = server.name
+        address = server.address
+        port = server.port
+        password = server.password
+        useHttps = server.useHttps
+    }
+
+    // Pairing QR scanned: dedupe against saved servers, then either auto-connect
+    // (payload carried a password — the demo flow) or land on the password
+    // prompt with everything else filled in (real nodes never embed one).
+    fun onQrScanned(scanned: ServerEntry) {
+        showScanner = false
+        scope.launch {
+            val merged = prefs.upsertServer(scanned)
+            prefill(merged)
+            if (merged.password.isNotBlank()) {
+                connect(merged)
+            } else {
+                manualMode = true
+            }
+        }
+    }
+
+    LaunchedEffect(initialServer) {
+        if (initialServer != null) {
+            prefill(prefs.upsertServer(initialServer))
+            manualMode = true
+        }
+    }
+
     Box(
         modifier = Modifier
             .fillMaxSize()
@@ -226,8 +265,10 @@ fun ServerConnectScreen(
                 textAlign = TextAlign.Center,
             )
 
+            val showForm = manualMode || editingServer != null
+
             Text(
-                text = stringResource(R.string.server_address_hint),
+                text = if (showForm) stringResource(R.string.server_address_hint) else stringResource(R.string.connect_landing_hint),
                 style = MaterialTheme.typography.bodyMedium,
                 color = TextMuted,
                 textAlign = TextAlign.Center,
@@ -235,8 +276,25 @@ fun ServerConnectScreen(
 
             Spacer(modifier = Modifier.height(4.dp))
 
+            if (!showForm) {
+                // Landing: scan the pairing QR, or fall back to manual entry
+                GlassButton(
+                    text = stringResource(R.string.scan_node_qr),
+                    onClick = { showScanner = true },
+                    modifier = Modifier.fillMaxWidth().height(56.dp),
+                )
+                GlassButton(
+                    text = stringResource(R.string.enter_manually),
+                    onClick = {
+                        errorMessage = null
+                        manualMode = true
+                    },
+                    modifier = Modifier.fillMaxWidth().height(56.dp),
+                )
+            }
+
             // Glass card with form
-            Box(
+            if (showForm) Box(
                 modifier = Modifier
                     .fillMaxWidth()
                     .clip(RoundedCornerShape(16.dp))
@@ -458,16 +516,30 @@ fun ServerConnectScreen(
                         modifier = Modifier.weight(1f).height(56.dp),
                     )
                 }
-            } else {
-                // Connect button — glass style
-                GlassButton(
-                    text = if (isConnecting) stringResource(R.string.connecting) else stringResource(R.string.connect),
-                    onClick = {
-                        keyboard?.hide()
-                        connect(ServerEntry(address, useHttps, port, password, name))
-                    },
-                    modifier = Modifier.fillMaxWidth().height(56.dp),
-                )
+            } else if (manualMode) {
+                // Back to the Scan/Manual landing + Connect
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalArrangement = Arrangement.spacedBy(12.dp),
+                ) {
+                    GlassButton(
+                        text = stringResource(R.string.back),
+                        onClick = {
+                            keyboard?.hide()
+                            manualMode = false
+                            clearForm()
+                        },
+                        modifier = Modifier.weight(1f).height(56.dp),
+                    )
+                    GlassButton(
+                        text = if (isConnecting) stringResource(R.string.connecting) else stringResource(R.string.connect),
+                        onClick = {
+                            keyboard?.hide()
+                            connect(ServerEntry(address, useHttps, port, password, name))
+                        },
+                        modifier = Modifier.weight(2f).height(56.dp),
+                    )
+                }
             }
 
             if (isConnecting) {
@@ -499,6 +571,12 @@ fun ServerConnectScreen(
                 }
             }
         }
+
+        QrScannerOverlay(
+            visible = showScanner,
+            onDismiss = { showScanner = false },
+            onServerScanned = { onQrScanned(it) },
+        )
     }
 }
 

Android/app/src/main/java/com/archipelago/app/ui/screens/WebViewScreen.kt

@@ -136,6 +136,10 @@ fun WebViewScreen(
     serverUrl: String,
     onDisconnect: () -> Unit,
     onRemoteInput: () -> Unit = {},
+    // Stored password for this server (from QR pairing or manual entry). When
+    // non-blank, the login page is auto-filled and submitted — the one-step
+    // demo flow from docs/companion-pairing-qr.md.
+    serverPassword: String = "",
 ) {
     var isLoading by remember { mutableStateOf(true) }
     var loadProgress by remember { mutableIntStateOf(0) }
@@ -310,6 +314,12 @@ fun WebViewScreen(
                                     """.trimIndent(),
                                     null,
                                 )
+
+                                // Auto-login with the stored password (QR pairing /
+                                // saved server) — only on our own server's pages.
+                                if (serverPassword.isNotBlank() && url != null && url.startsWith(serverUrl)) {
+                                    view.evaluateJavascript(buildAutoLoginScript(serverPassword), null)
+                                }
                             }
 
                             override fun onReceivedError(
@@ -700,3 +710,39 @@ private fun InAppBrowser(
         }
     }
 }
+
+/**
+ * JS that fills the web UI login form (Login.vue's #login-password) with the
+ * stored password and submits it once the form is interactive — the one-step
+ * pairing flow. No-ops when the login step never appears (already
+ * authenticated, first-boot setup, TOTP). At most two attempts per page load,
+ * then it stops for good so a wrong stored password can't spam the node.
+ */
+private fun buildAutoLoginScript(password: String): String {
+    val quoted = org.json.JSONObject.quote(password)
+    return """
+    (function () {
+        if (window.__archyAutoLogin) return;
+        window.__archyAutoLogin = true;
+        var pw = $quoted;
+        var attempts = 0;
+        var started = Date.now();
+        var timer = setInterval(function () {
+            if (Date.now() - started > 45000) { clearInterval(timer); return; }
+            var el = document.getElementById('login-password');
+            if (!el) {
+                // Field gone after we submitted = success or step change - stop.
+                if (attempts > 0) clearInterval(timer);
+                return;
+            }
+            if (el.disabled) return; // form waits on serverReady
+            if (attempts >= 2) { clearInterval(timer); return; }
+            attempts++;
+            var setter = Object.getOwnPropertyDescriptor(window.HTMLInputElement.prototype, 'value').set;
+            setter.call(el, pw);
+            el.dispatchEvent(new Event('input', { bubbles: true }));
+            el.dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter', bubbles: true }));
+        }, 1500);
+    })();
+    """.trimIndent()
+}

Android/app/src/main/res/values/strings.xml

@@ -29,6 +29,15 @@
     <string name="server_name_label">Server Name (optional)</string>
     <string name="server_name_placeholder">My Archipelago</string>
     <string name="edit_server">Edit</string>
+    <string name="scan_node_qr">Scan Node\'s QR</string>
+    <string name="enter_manually">Enter Manually</string>
+    <string name="connect_landing_hint">Scan the pairing QR from your node\'s Companion popup, or enter the address manually</string>
+    <string name="scan_qr_hint">Point the camera at the pairing QR shown in the Companion popup</string>
+    <string name="camera_permission_needed">Camera access is needed to scan the pairing QR. You can also enter the server details manually.</string>
+    <string name="grant_camera_access">Grant Camera Access</string>
+    <string name="invalid_pairing_qr">Not an Archipelago pairing code</string>
+    <string name="update_app_for_qr">This pairing code needs a newer app version — please update the companion app</string>
+    <string name="add_server_qr">Add server by QR</string>
     <string name="edit_server_title">Edit Server</string>
     <string name="save_changes">Save Changes</string>
     <string name="cancel">Cancel</string>

docs/companion-pairing-qr.md

@@ -42,9 +42,9 @@ Examples the web UI actually emits:
 
 ## Companion app requirements
 
-1. **Scan entry point:** a "Scan node code" action (screen-2 copy in the web UI
-   says: *"In the companion app, choose 'Scan node code' and point your phone
-   here"* — keep that wording or tell me the real label so I update the modal).
+1. **Scan entry point:** the app's action is labeled **"Scan Node's QR"**
+   (implemented 2026-07-17; the modal copy in CompanionIntroOverlay.vue was
+   updated to match).
 2. **Parse the URI** (from camera scan AND from an OS deep-link intent —
    register the `archipelago://` scheme so the "Open in companion app" button on
    phones works).

neode-ui/src/components/CompanionIntroOverlay.vue

@@ -86,7 +86,7 @@
                 <div class="min-w-0 flex-1">
                   <h3 class="text-lg font-semibold text-white mb-1">Connect your app</h3>
                   <p class="text-sm text-white/60 leading-relaxed">
-                    In the companion app, choose “Scan node code” and point your phone here — the server details fill in automatically.
+                    In the companion app, choose “Scan Node's QR” and point your phone here — the server details fill in automatically.
                   </p>
                 </div>
               </div>