feat(deeplinks): implement deep link handling for jam sessions

composeApp/src/androidMain/AndroidManifest.xml

@@ -55,6 +55,17 @@
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <!-- Group Jam invite/answer deep links: spotube://jam/... -->
+            <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:host="jam"
+                    android:scheme="spotube" />
+            </intent-filter>
         </activity>
         <service
             android:name=".media.PlaybackService"

composeApp/src/androidMain/kotlin/dev/krtirtho/spotube/MainActivity.kt

@@ -17,10 +17,12 @@
 
 package dev.krtirtho.spotube
 
+import android.content.Intent
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import dev.krtirtho.spotube.core.deeplink.ExternalUriHandler
 import dev.krtirtho.spotube.core.newpipe.NewPipeDownloader
 import dev.krtirtho.spotube.core.paths.Paths
 import io.github.vinceglb.filekit.FileKit
@@ -32,8 +34,14 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         FileKit.init(this)
         NewPipeDownloader.init(Paths(this))
+        intent?.dataString?.let(ExternalUriHandler::onNewUri)
         setContent {
             App()
         }
     }
+
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        intent.dataString?.let(ExternalUriHandler::onNewUri)
+    }
 }

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/App.kt

@@ -24,6 +24,7 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
 import dev.krtirtho.spotube.core.ui.base.LocalBaseUITheme
@@ -32,6 +33,8 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation3.ui.NavDisplay
+import dev.krtirtho.spotube.core.deeplink.ExternalUriHandler
+import dev.krtirtho.spotube.core.deeplink.JamDeepLinkService
 import dev.krtirtho.spotube.core.navigation.Navigator
 import dev.krtirtho.spotube.core.navigation.Routes
 import dev.krtirtho.spotube.core.navigation.TOP_LEVEL_ROUTES
@@ -103,6 +106,12 @@ fun App(
     val settingsRepository: SettingsRepository = koinInject<SettingsRepository>()
     val userSettings by settingsRepository.userSettings.collectAsStateWithLifecycle(initialValue = UserSettings())
 
+    val jamDeepLinks: JamDeepLinkService = koinInject()
+    DisposableEffect(Unit) {
+        ExternalUriHandler.listener = { uri -> jamDeepLinks.handleUri(uri) }
+        onDispose { ExternalUriHandler.listener = null }
+    }
+
     val navigationState = rememberNavigationState(
         startRoute = Routes.Home,
         topLevelRoutes = TOP_LEVEL_ROUTES

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/deeplink/ExternalUriHandler.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2026 Kingkor Roy Tirtho and Spotube Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package dev.krtirtho.spotube.core.deeplink
+
+/**
+ * Cross-platform receiver for URIs handed to the app by the operating system
+ * (deep links). Platform entry points (Android activity intents, desktop command
+ * line / open-URI handler, iOS `onOpenURL`) call [onNewUri]; the main composable
+ * installs a [listener] once composition starts.
+ *
+ * Follows the Compose Multiplatform deep linking docs pattern: URIs arriving
+ * before a listener is installed are cached and delivered as soon as one is set.
+ */
+object ExternalUriHandler {
+    private var cached: String? = null
+
+    var listener: ((uri: String) -> Unit)? = null
+        set(value) {
+            field = value
+            if (value != null) {
+                cached?.let(value::invoke)
+                cached = null
+            }
+        }
+
+    fun onNewUri(uri: String) {
+        if (uri.isBlank()) return
+        val currentListener = listener
+        if (currentListener != null) {
+            currentListener(uri)
+        } else {
+            cached = uri
+        }
+    }
+}

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/deeplink/JamDeepLinkService.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2026 Kingkor Roy Tirtho and Spotube Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package dev.krtirtho.spotube.core.deeplink
+
+import dev.krtirtho.spotube.core.jam.JamInviteCodec
+import dev.krtirtho.spotube.core.jam.JamInviteLink
+import dev.krtirtho.spotube.core.navigation.NavigationCommands
+import dev.krtirtho.spotube.core.navigation.Routes
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * Parses incoming `spotude://jam/...` deep links, exposes them to the Jam UI,
+ * and navigates to [Routes.Jam] so the user lands where the link is handled.
+ */
+class JamDeepLinkService(
+    private val navigationCommands: NavigationCommands,
+) {
+    private val _pendingLink = MutableStateFlow<JamInviteLink?>(null)
+    val pendingLink: StateFlow<JamInviteLink?> = _pendingLink.asStateFlow()
+
+    fun handleUri(uri: String) {
+        val link = JamInviteCodec.parse(uri) ?: return
+        _pendingLink.value = link
+        navigationCommands.navigateTo(Routes.Jam)
+    }
+
+    /** Consumes the currently pending link (if any). */
+    fun consume(): JamInviteLink? = _pendingLink.value.also { _pendingLink.value = null }
+
+    fun clear() {
+        _pendingLink.value = null
+    }
+}

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/di/Modules.kt

@@ -23,6 +23,7 @@ import dev.krtirtho.spotube.core.audioplayer.AudioPlayerQueueRepository
 import dev.krtirtho.spotube.core.audioplayer.DeviceAudioPlayerQueue
 import dev.krtirtho.spotube.core.audioplayer.QueueStateRepository
 import dev.krtirtho.spotube.core.db.Database
+import dev.krtirtho.spotube.core.deeplink.JamDeepLinkService
 import dev.krtirtho.spotube.core.discovery.DeviceDiscoveryService
 import dev.krtirtho.spotube.core.discord.DiscordRpcService
 import dev.krtirtho.spotube.core.jam.JamSessionService
@@ -219,6 +220,7 @@ val sharedModules = module {
         createdAtStart()
     }
     single { JamSessionService(get(), get()) }
+    singleOf(::JamDeepLinkService)
     singleOf(::AudioPlayerQueueRepository) { bind<QueueStateRepository>() }
     single<AudioPlayerQueue> {
         DeviceAudioPlayerQueue(get(), get(), get(), get(), get())

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/discovery/DeviceDiscoveryService.kt

@@ -23,6 +23,7 @@ import com.appstractive.dnssd.createNetService
 import com.appstractive.dnssd.discoverServices
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
+import kotlin.text.decodeToString
 
 data class DiscoveredDevice(
     val name: String,
@@ -54,7 +55,7 @@ class DeviceDiscoveryService {
                     type = event.service.type,
                     host = event.service.host,
                     port = event.service.port,
-                    deviceId = event.service.txt[TXT_DEVICE_ID]?.let { String(it) }.orEmpty(),
+                    deviceId = event.service.txt[TXT_DEVICE_ID]?.decodeToString().orEmpty(),
                 )
                 DiscoveryState.Discovered(device = device, resolve = event.resolve)
             }
@@ -65,7 +66,7 @@ class DeviceDiscoveryService {
                     type = event.service.type,
                     host = event.service.host,
                     port = event.service.port,
-                    deviceId = event.service.txt[TXT_DEVICE_ID]?.let { String(it) }.orEmpty(),
+                    deviceId = event.service.txt[TXT_DEVICE_ID]?.decodeToString().orEmpty(),
                 )
                 DiscoveryState.Resolved(device = device)
             }

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/jam/JamInviteCodec.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2026 Kingkor Roy Tirtho and Spotube Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package dev.krtirtho.spotube.core.jam
+
+import io.ktor.http.decodeURLQueryComponent
+import io.ktor.http.encodeURLParameter
+
+/**
+ * SDP payloads exchanged between jam peers are wrapped into `spotube://` deep links
+ * so they can be shared through any messaging medium. The SDP blob is percent-encoded
+ * as a query parameter.
+ *
+ * Host invite  : `spotube://jam/invite?name=<host name>&sdp=<offer sdp>`
+ * Guest answer : `spotube://jam/answer?name=<guest name>&sdp=<answer sdp>`
+ */
+sealed interface JamInviteLink {
+    val peerName: String
+    val sdp: String
+
+    data class HostInvite(
+        override val peerName: String,
+        override val sdp: String,
+    ) : JamInviteLink
+
+    data class GuestAnswer(
+        override val peerName: String,
+        override val sdp: String,
+    ) : JamInviteLink
+}
+
+object JamInviteCodec {
+    const val SCHEME = "spotube"
+    const val INVITE_PATH = "jam/invite"
+    const val ANSWER_PATH = "jam/answer"
+
+    fun buildHostInvite(hostName: String, offerSdp: String): String =
+        buildLink(INVITE_PATH, hostName, offerSdp)
+
+    fun buildGuestAnswer(guestName: String, answerSdp: String): String =
+        buildLink(ANSWER_PATH, guestName, answerSdp)
+
+    private fun buildLink(path: String, peerName: String, sdp: String): String =
+        "$SCHEME://$path?name=${peerName.encodeURLParameter()}" +
+            "&sdp=${sdp.encodeURLParameter()}"
+
+    /**
+     * Parses a `spotude://jam/...` link. Returns null for foreign or malformed URIs.
+     * Parsing is done manually — generic URI parsers normalize unknown schemes in
+     * ways that mangle percent-encoded multi-line payloads.
+     */
+    fun parse(rawUri: String): JamInviteLink? {
+        val uri = rawUri.trim()
+        if (!uri.startsWith("$SCHEME://", ignoreCase = true)) return null
+
+        val withoutScheme = uri.substring(SCHEME.length + 3)
+        val queryStart = withoutScheme.indexOf('?')
+        if (queryStart < 0) return null
+
+        val path = withoutScheme.take(queryStart).trim('/').lowercase()
+        val params = withoutScheme.substring(queryStart + 1)
+            .split('&')
+            .mapNotNull { pair ->
+                val separator = pair.indexOf('=')
+                if (separator <= 0) return@mapNotNull null
+                pair.take(separator) to pair.substring(separator + 1)
+            }
+            .toMap()
+
+        val sdp = params["sdp"]?.decodeURLQueryComponent()?.takeIf { it.isNotBlank() }
+            ?: return null
+        val peerName = params["name"]?.decodeURLQueryComponent().orEmpty()
+
+        return when (path) {
+            INVITE_PATH -> JamInviteLink.HostInvite(peerName, sdp)
+            ANSWER_PATH -> JamInviteLink.GuestAnswer(peerName, sdp)
+            else -> null
+        }
+    }
+
+    /**
+     * Extracts an SDP payload from user input which may either be a full
+     * `spotube://` deep link or a raw SDP body pasted by hand.
+     */
+    fun extractSdp(rawInput: String): String? {
+        val input = rawInput.trim()
+        parse(input)?.let { return it.sdp }
+        // Heuristic for raw SDP: first line is the session description header
+        return if (input.startsWith("v=", ignoreCase = false)) input else null
+    }
+}

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/jam/JamSessionService.kt

@@ -23,6 +23,7 @@ import dev.krtirtho.spotube.core.di.injectLogger
 import dev.krtirtho.spotube.modules.settings.SettingsProvider
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.IO
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -38,6 +39,16 @@ import uniffi.compose_app.WebrtcEventHandler
 import uniffi.compose_app.WebrtcPeerConnection
 import uniffi.compose_app.createWebrtcPeerConnection
 
+/**
+ * An invite generated by the host for one guest slot. The [sdp] offer is shared
+ * via a deep link; once the guest's answer comes back, [JamSessionService.acceptAnswer]
+ * completes the handshake for that slot.
+ */
+data class JamInvite(
+    val id: String,
+    val sdp: String,
+)
+
 class JamSessionService(
     private val audioPlayer: AudioPlayerInterface,
     private val settingsProvider: SettingsProvider,
@@ -66,100 +77,109 @@ class JamSessionService(
     private val _incomingMessages = MutableSharedFlow<JamMessage>(extraBufferCapacity = 64)
     val incomingMessages = _incomingMessages.asSharedFlow()
 
-    private val scope = CoroutineScope(Dispatchers.IO + SupervisorJob())
-
     private val _incomingSuggestions = MutableSharedFlow<JamMessage>(extraBufferCapacity = 32)
     val incomingSuggestions = _incomingSuggestions.asSharedFlow()
 
+    private val scope = CoroutineScope(Dispatchers.IO + SupervisorJob())
+
+    /** Host side: invites whose answers have not arrived yet. */
+    private val pendingInvites = mutableMapOf<String, WebrtcPeerConnection>()
+
+    /** Host side: guests whose handshake completed. Keyed by invite id. */
+    private val connectedGuests = mutableMapOf<String, WebrtcPeerConnection>()
+
+    /** Guest side: the single connection to the host. */
     private var hostConnection: WebrtcPeerConnection? = null
-    private val guestConnections = mutableMapOf<String, WebrtcPeerConnection>()
-    private val guestLabels = mutableMapOf<String, String>()
-
-    private val eventHandler = object : WebrtcEventHandler {
-        override fun onIceCandidate(candidate: String) {
-            // No-op in non-trickle mode: candidates are bundled into SDP
-        }
-
-        override fun onIceGatheringStateChange(state: String) {
-            log.d { "ICE gathering state: $state" }
-        }
-
-        override fun onConnectionStateChange(state: String) {
-            log.i { "Connection state: $state" }
-        }
-
-        override fun onDataChannelOpen(label: String) {
-            log.i { "Data channel '$label' open" }
-        }
-
-        override fun onDataChannelMessage(label: String, data: String) {
-            handleIncomingMessage(label, data)
-        }
-
-        override fun onDataChannelClose(label: String) {
-            log.i { "Data channel '$label' closed" }
-        }
-    }
 
     suspend fun createSession(): String {
         log.i { "Creating jam session" }
-        val settings = settingsProvider.settingsState.first()
-        val participantName = settings?.jamParticipantName?.ifBlank {
-            "Host-${randomShortId()}"
-        } ?: "Host"
+        val hostName = resolveParticipantName(defaultPrefix = "Host")
 
-        val pc = createWebrtcPeerConnection(
-            iceServers = listOf(
-                IceServerConfig(
-                    urls = listOf("stun:stun.l.google.com:19302"),
-                    username = "",
-                    credential = "",
-                )
-            ),
-            handler = eventHandler,
-        )
-
-        hostConnection = pc
         _role.value = JamRole.Host
         _localParticipantId.value = "host"
         _participants.value = listOf(
             JamParticipant(
                 id = "host",
-                displayName = participantName,
+                displayName = hostName,
                 isHost = true,
             )
         )
         _isActive.value = true
 
-        pc.createDataChannel("jam")
-        val offer = pc.createOffer()
-        log.i { "Generated SDP offer (length=${offer.length})" }
-        return offer
+        return generateInvite().sdp
     }
 
-    suspend fun acceptGuestAnswer(guestId: String, answer: String) {
-        val pc = guestConnections[guestId] ?: run {
-            log.w { "acceptGuestAnswer: no connection for $guestId" }
-            return
+    /**
+     * Generates a new invite (peer connection + SDP offer with bundled ICE candidates).
+     * Each invite admits exactly one guest.
+     */
+    suspend fun generateInvite(): JamInvite {
+        if (_role.value != JamRole.Host) {
+            error("generateInvite can only be called by the host")
         }
-        pc.setRemoteAnswer(answer)
-    }
-
-    suspend fun joinSession(offer: String): String {
-        log.i { "Joining jam session" }
-        val settings = settingsProvider.settingsState.first()
-        val participantName = settings?.jamParticipantName?.ifBlank {
-            "Guest-${randomShortId()}"
-        } ?: "Guest"
+        val inviteId = "guest-${randomShortId()}"
+        log.i { "Generating invite $inviteId" }
 
         val pc = createWebrtcPeerConnection(
-            iceServers = listOf(
-                IceServerConfig(
-                    urls = listOf("stun:stun.l.google.com:19302"),
-                    username = "",
-                    credential = "",
+            iceServers = listOf(defaultIceServer()),
+            handler = guestEventHandler(inviteId),
         )
-            ),
+
+        pc.createDataChannel(CHANNEL_LABEL)
+        val offer = pc.createOffer()
+        pendingInvites[inviteId] = pc
+        return JamInvite(id = inviteId, sdp = offer)
+    }
+
+    /**
+     * Completes a guest's handshake: applies their SDP answer to the peer connection
+     * created for [inviteId] and adds them to the participant list.
+     *
+     * When [inviteId] is null, the oldest still-pending invite is used — convenient
+     * when an answer deep link arrives out of band.
+     *
+     * @param answerSdp raw SDP answer body (not a deep link).
+     * @param peerName display name of the guest, taken from their answer link if available.
+     */
+    suspend fun acceptAnswer(inviteId: String?, answerSdp: String, peerName: String): Boolean {
+        if (_role.value != JamRole.Host) {
+            log.w { "acceptAnswer ignored: not hosting" }
+            return false
+        }
+        val resolvedId = inviteId ?: pendingInvites.keys.firstOrNull()
+        if (resolvedId == null) {
+            log.w { "acceptAnswer: no pending invite" }
+            return false
+        }
+        val pc = pendingInvites.remove(resolvedId)
+        if (pc == null) {
+            log.w { "acceptAnswer: no pending invite '$resolvedId'" }
+            return false
+        }
+        runCatching { pc.setRemoteAnswer(answerSdp) }
+            .onFailure { e ->
+                log.w(e) { "Failed to apply answer for $inviteId" }
+                scope.launch { runCatching { pc.shutdown() } }
+                return false
+            }
+        connectedGuests[resolvedId] = pc
+        _participants.update { current ->
+            current + JamParticipant(
+                id = resolvedId,
+                displayName = peerName.ifBlank { "Guest-${resolvedId.takeLast(4)}" },
+                isHost = false,
+            )
+        }
+        log.i { "Guest $resolvedId ($peerName) joined" }
+        return true
+    }
+
+    suspend fun joinSession(offerSdp: String): String {
+        log.i { "Joining jam session" }
+        val participantName = resolveParticipantName(defaultPrefix = "Guest")
+
+        val pc = createWebrtcPeerConnection(
+            iceServers = listOf(defaultIceServer()),
             handler = eventHandler,
         )
 
@@ -168,65 +188,31 @@ class JamSessionService(
         _localParticipantId.value = "guest"
         _isActive.value = true
 
-        pc.setRemoteOffer(offer)
-        pc.createDataChannel("jam")
+        // The data channel arrives in-band from the host's offer via on_data_channel;
+        // we only answer here.
+        pc.setRemoteOffer(offerSdp)
         val answer = pc.createAnswer()
         log.i { "Generated SDP answer (length=${answer.length})" }
         return answer
     }
 
-    suspend fun hostAdmitGuest(guestOffer: String): String {
-        if (_role.value != JamRole.Host) {
-            error("hostAdmitGuest can only be called by the host")
-        }
-        val guestId = "guest-${guestConnections.size + 1}"
-        log.i { "Admitting guest $guestId" }
-
-        val handler = object : WebrtcEventHandler {
-            override fun onIceCandidate(candidate: String) {}
-            override fun onIceGatheringStateChange(state: String) {}
-            override fun onConnectionStateChange(state: String) {}
-            override fun onDataChannelOpen(label: String) {}
-            override fun onDataChannelMessage(label: String, data: String) {
-                handleIncomingMessage(label, data, guestId)
-            }
-            override fun onDataChannelClose(label: String) {}
-        }
-
-        val pc = createWebrtcPeerConnection(
-            iceServers = listOf(
-                IceServerConfig(
-                    urls = listOf("stun:stun.l.google.com:19302"),
-                    username = "",
-                    credential = "",
-                )
-            ),
-            handler = handler,
-        )
-        guestConnections[guestId] = pc
-        guestLabels[guestId] = "jam-$guestId"
-
-        pc.setRemoteOffer(guestOffer)
-        pc.createDataChannel("jam-${guestId}")
-        val answer = pc.createAnswer()
-        return answer
-    }
-
     suspend fun sendMessage(message: JamMessage, guestId: String? = null) {
-        val json = json.encodeToString(JamMessage.serializer(), message)
+        val payload = json.encodeToString(JamMessage.serializer(), message)
         when (_role.value) {
             JamRole.Host -> {
-                if (guestId != null) {
-                    guestConnections[guestId]?.sendData("jam-$guestId", json)
+                val targets = if (guestId != null) {
+                    listOfNotNull(connectedGuests[guestId])
                 } else {
-                    guestConnections.forEach { (id, pc) ->
-                        pc.sendData("jam-$id", json)
+                    connectedGuests.values.toList()
                 }
+                targets.forEach { pc ->
+                    runCatching { pc.sendData(CHANNEL_LABEL, payload) }
+                        .onFailure { e -> log.w(e) { "Failed to send to guest" } }
                 }
             }
 
             JamRole.Guest -> {
-                hostConnection?.sendData("jam", json)
+                hostConnection?.sendData(CHANNEL_LABEL, payload)
             }
 
             null -> log.w { "sendMessage called while no session is active" }
@@ -236,46 +222,13 @@ class JamSessionService(
     suspend fun leave() {
         log.i { "Leaving jam session" }
         runCatching { sendMessage(JamMessage.Leave()) }
-        hostConnection?.shutdown()
-        guestConnections.values.forEach { runCatching { it.shutdown() } }
-        hostConnection = null
-        guestConnections.clear()
-        guestLabels.clear()
+        shutdownAll()
         _role.value = null
         _participants.value = emptyList()
         _isActive.value = false
         _localParticipantId.value = null
     }
 
-    private fun handleIncomingMessage(label: String, data: String, fromGuestId: String? = null) {
-        try {
-            val message = json.decodeFromString(JamMessage.serializer(), data)
-            _incomingMessages.tryEmit(message)
-            when (message) {
-                is JamMessage.SuggestTrack, is JamMessage.SuggestPlaylist -> {
-                    _incomingSuggestions.tryEmit(message)
-                }
-
-                is JamMessage.Leave -> {
-                    if (_role.value == JamRole.Host && fromGuestId != null) {
-                        val leavingPc = guestConnections.remove(fromGuestId)
-                        guestLabels.remove(fromGuestId)
-                        scope.launch {
-                            runCatching { leavingPc?.shutdown() }
-                        }
-                        _participants.update { current ->
-                            current.filterNot { it.id == fromGuestId }
-                        }
-                    }
-                }
-
-                else -> Unit
-            }
-        } catch (e: Exception) {
-            log.w(e) { "Failed to parse jam message on $label" }
-        }
-    }
-
     suspend fun broadcastPlaybackCommand(command: PlaybackCmd) {
         if (_role.value != JamRole.Host) return
         sendMessage(JamMessage.PlaybackCommand(command))
@@ -300,8 +253,113 @@ class JamSessionService(
         if (_role.value != JamRole.Guest) return
         sendMessage(JamMessage.SuggestPlaylist(tracks))
     }
+
+    private fun defaultIceServer() = IceServerConfig(
+        urls = listOf("stun:stun.l.google.com:19302"),
+        username = "",
+        credential = "",
+    )
+
+    private suspend fun resolveParticipantName(defaultPrefix: String): String {
+        val settings = settingsProvider.settingsState.first()
+        return settings?.jamParticipantName?.ifBlank { "$defaultPrefix-${randomShortId()}" }
+            ?: "$defaultPrefix-${randomShortId()}"
+    }
+
+    /**
+     * Per-guest handler so messages received on a guest's connection can be
+     * attributed back to that guest (needed for kick-on-leave and targeted sends).
+     */
+    private fun guestEventHandler(guestId: String) = object : WebrtcEventHandler {
+        override fun onIceCandidate(candidate: String) {}
+
+        override fun onIceGatheringStateChange(state: String) {
+            log.d { "[$guestId] ICE gathering state: $state" }
+        }
+
+        override fun onConnectionStateChange(state: String) {
+            log.i { "[$guestId] Connection state: $state" }
+        }
+
+        override fun onDataChannelOpen(label: String) {
+            log.i { "[$guestId] Data channel '$label' open" }
+        }
+
+        override fun onDataChannelMessage(label: String, data: String) {
+            handleIncomingMessage(data, fromGuestId = guestId)
+        }
+
+        override fun onDataChannelClose(label: String) {
+            log.i { "[$guestId] Data channel closed" }
+        }
+    }
+
+    private val eventHandler = object : WebrtcEventHandler {
+        override fun onIceCandidate(candidate: String) {}
+
+        override fun onIceGatheringStateChange(state: String) {
+            log.d { "ICE gathering state: $state" }
+        }
+
+        override fun onConnectionStateChange(state: String) {
+            log.i { "Connection state: $state" }
+        }
+
+        override fun onDataChannelOpen(label: String) {
+            log.i { "Data channel '$label' open" }
+        }
+
+        override fun onDataChannelMessage(label: String, data: String) {
+            handleIncomingMessage(data, fromGuestId = null)
+        }
+
+        override fun onDataChannelClose(label: String) {
+            log.i { "Data channel closed" }
+        }
+    }
+
+    private fun handleIncomingMessage(data: String, fromGuestId: String?) {
+        try {
+            val message = json.decodeFromString(JamMessage.serializer(), data)
+            _incomingMessages.tryEmit(message)
+            when (message) {
+                is JamMessage.SuggestTrack, is JamMessage.SuggestPlaylist -> {
+                    _incomingSuggestions.tryEmit(message)
+                }
+
+                is JamMessage.Leave -> {
+                    if (_role.value == JamRole.Host && fromGuestId != null) {
+                        val leavingPc = connectedGuests.remove(fromGuestId)
+                        scope.launch {
+                            runCatching { leavingPc?.shutdown() }
+                        }
+                        _participants.update { current ->
+                            current.filterNot { it.id == fromGuestId }
+                        }
+                    } else if (_role.value == JamRole.Guest) {
+                        scope.launch { leave() }
+                    }
+                }
+
+                else -> Unit
+            }
+        } catch (e: Exception) {
+            log.w(e) { "Failed to parse jam message" }
+        }
+    }
+
+    private suspend fun shutdownAll() {
+        pendingInvites.values.forEach { runCatching { it.shutdown() } }
+        connectedGuests.values.forEach { runCatching { it.shutdown() } }
+        runCatching { hostConnection?.shutdown() }
+        pendingInvites.clear()
+        connectedGuests.clear()
+        hostConnection = null
+    }
 }
 
+private const val CHANNEL_LABEL = "jam"
+
 private fun <T> MutableStateFlow<T>.update(transform: (T) -> T) {
     value = transform(value)
 }

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/modules/jam/JamScreen.kt

@@ -19,12 +19,17 @@ package dev.krtirtho.spotube.modules.jam
 
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.text.selection.SelectionContainer
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Button
+import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.SegmentedButton
@@ -32,15 +37,20 @@ import androidx.compose.material3.SegmentedButtonDefaults
 import androidx.compose.material3.SingleChoiceSegmentedButtonRow
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalClipboardManager
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import dev.krtirtho.spotube.core.jam.JamRole
 import dev.krtirtho.spotube.core.navigation.NavigationCommands
 import dev.krtirtho.spotube.core.ui.component.ApplicationMainBar
 import org.koin.compose.viewmodel.koinViewModel
@@ -50,17 +60,7 @@ fun JamScreen(
     navigationCommands: NavigationCommands,
 ) {
     val viewModel = koinViewModel<JamViewModel>()
-    val isActive by viewModel.isActive.collectAsStateWithLifecycle()
-    val pendingOffer by viewModel.pendingHostOffer.collectAsStateWithLifecycle()
-    val pendingAnswer by viewModel.pendingGuestAnswer.collectAsStateWithLifecycle()
-    val error by viewModel.error.collectAsStateWithLifecycle()
-
-    LaunchedEffect(isActive) {
-        if (isActive && navigationCommands != null) {
-            // navigationCommands doesn't navigate here automatically;
-            // the session screen is the same screen so we just stay.
-        }
-    }
+    val state by viewModel.uiState.collectAsStateWithLifecycle()
 
     Scaffold(
         topBar = {
@@ -74,33 +74,54 @@ fun JamScreen(
             modifier = Modifier
                 .fillMaxSize()
                 .padding(innerPadding)
-                .padding(16.dp),
+                .padding(16.dp)
+                .verticalScroll(rememberScrollState()),
             verticalArrangement = Arrangement.spacedBy(16.dp),
         ) {
-            if (error != null) {
+            state.error?.let { error ->
+                ErrorBanner(text = error, onDismiss = viewModel::clearError)
+            }
+
+            when {
+                !state.isActive && state.incomingOfferSdp != null -> IncomingInviteView(
+                    hostName = state.incomingHostName.orEmpty(),
+                    onJoin = viewModel::joinWithIncomingInvite,
+                    onDismiss = viewModel::dismissIncomingInvite,
+                )
+
+                !state.isActive -> CreateOrJoinView(
+                    onCreate = viewModel::createSession,
+                    onJoin = viewModel::joinWithPasted,
+                )
+
+                state.role == JamRole.Host -> HostSessionView(
+                    state = state,
+                    onNewInvite = viewModel::generateNewInvite,
+                    onSubmitAnswer = viewModel::submitAnswerPasted,
+                    onShare = viewModel::share,
+                    onLeave = viewModel::leave,
+                )
+
+                else -> GuestSessionView(
+                    state = state,
+                    onShare = viewModel::share,
+                    onLeave = viewModel::leave,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun ErrorBanner(text: String, onDismiss: () -> Unit) {
+    Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
         Text(
-                    text = error ?: "",
+            text = text,
             color = MaterialTheme.colorScheme.error,
             style = MaterialTheme.typography.bodyMedium,
         )
-            }
-
-            if (pendingOffer == null && pendingAnswer == null) {
-                CreateOrJoinView(
-                    onCreate = { viewModel.createSession() },
-                    onJoin = { offer -> viewModel.joinSession(offer) },
-                )
-            } else if (pendingOffer != null) {
-                HostOfferView(
-                    offer = pendingOffer!!,
-                    onLeave = { viewModel.leave() },
-                )
-            } else if (pendingAnswer != null) {
-                GuestAnswerView(
-                    answer = pendingAnswer!!,
-                    onLeave = { viewModel.leave() },
-                )
-            }
+        OutlinedButton(onClick = onDismiss) {
+            Text("Dismiss")
         }
     }
 }
@@ -111,12 +132,12 @@ private fun CreateOrJoinView(
     onJoin: (String) -> Unit,
 ) {
     var tab by remember { mutableIntStateOf(0) }
-    var offer by remember { mutableStateOf("") }
+    var pasted by rememberSaveable { mutableStateOf("") }
 
     Column(verticalArrangement = Arrangement.spacedBy(16.dp)) {
         Text(
-            text = "Listen Together with friends",
-            style = MaterialTheme.typography.titleLarge,
+            text = "Listen together with friends over a peer-to-peer connection.",
+            style = MaterialTheme.typography.titleMedium,
         )
 
         SingleChoiceSegmentedButtonRow(modifier = Modifier.fillMaxWidth()) {
@@ -135,8 +156,10 @@ private fun CreateOrJoinView(
         if (tab == 0) {
             Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
                 Text(
-                    text = "Create a new jam session. You'll be the host and can control playback. Share the SDP offer with your friends so they can join.",
+                    text = "Start a session as the host. You'll get a shareable invite link " +
+                        "to send to friends; when they accept, they appear here.",
                     style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
                 Button(onClick = onCreate) {
                     Text("Create Session")
@@ -145,22 +168,24 @@ private fun CreateOrJoinView(
         } else {
             Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
                 Text(
-                    text = "Paste the SDP offer from the host below. You'll get an SDP answer to send back.",
+                    text = "Paste the invite link the host shared with you.",
                     style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
                 OutlinedTextField(
-                    value = offer,
-                    onValueChange = { offer = it },
+                    value = pasted,
+                    onValueChange = { pasted = it },
                     modifier = Modifier.fillMaxWidth(),
-                    label = { Text("Host's SDP offer") },
-                    minLines = 3,
+                    label = { Text("Invite link") },
+                    placeholder = { Text("spotube://jam/invite?...") },
+                    minLines = 2,
                     maxLines = 6,
                 )
                 Button(
-                    onClick = { onJoin(offer.trim()) },
-                    enabled = offer.isNotBlank(),
+                    onClick = { onJoin(pasted) },
+                    enabled = pasted.isNotBlank(),
                 ) {
-                    Text("Generate Answer")
+                    Text("Join Session")
                 }
             }
         }
@@ -168,60 +193,196 @@ private fun CreateOrJoinView(
 }
 
 @Composable
-private fun HostOfferView(
-    offer: String,
-    onLeave: () -> Unit,
+private fun IncomingInviteView(
+    hostName: String,
+    onJoin: () -> Unit,
+    onDismiss: () -> Unit,
 ) {
     Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
         Text(
-            text = "Session created. Send this SDP offer to your friends:",
-            style = MaterialTheme.typography.bodyMedium,
+            text = "$hostName invited you to a jam session",
+            style = MaterialTheme.typography.titleMedium,
         )
-        SelectionContainer {
-            OutlinedTextField(
-                value = offer,
-                onValueChange = {},
-                readOnly = true,
-                modifier = Modifier.fillMaxWidth(),
-                label = { Text("SDP Offer (copy and send to guests)") },
-                minLines = 4,
-                maxLines = 10,
+        Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            Button(onClick = onJoin) {
+                Text("Join")
+            }
+            OutlinedButton(onClick = onDismiss) {
+                Text("Ignore")
+            }
+        }
+    }
+}
+
+@Composable
+private fun HostSessionView(
+    state: JamUiState,
+    onNewInvite: () -> Unit,
+    onSubmitAnswer: (String) -> Unit,
+    onShare: (String) -> Unit,
+    onLeave: () -> Unit,
+) {
+    val clipboard = LocalClipboardManager.current
+    var pastedAnswer by rememberSaveable { mutableStateOf("") }
+
+    Column(verticalArrangement = Arrangement.spacedBy(16.dp)) {
+        ParticipantsSection(state.participants)
+
+        HorizontalDivider()
+
+        Text(
+            text = "Invite someone",
+            style = MaterialTheme.typography.titleSmall,
+        )
+        val inviteLink = state.inviteLink
+        if (inviteLink != null) {
+            ShareableLinkBox(
+                label = "Invite link",
+                link = inviteLink,
+                onCopy = { clipboard.setText(AnnotatedString(inviteLink)) },
+                onShare = { onShare(inviteLink) },
             )
         }
+        OutlinedButton(onClick = onNewInvite) {
+            Text("Generate new invite")
+        }
+
+        HorizontalDivider()
+
         Text(
-            text = "When a guest responds with an SDP answer, use the JamSessionScreen to add them.",
+            text = "Accept a guest's answer",
+            style = MaterialTheme.typography.titleSmall,
+        )
+        Text(
+            text = "When your guest sends back their answer link, paste it below.",
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
-        Button(onClick = onLeave) {
-            Text("Leave Session")
+        OutlinedTextField(
+            value = pastedAnswer,
+            onValueChange = { pastedAnswer = it },
+            modifier = Modifier.fillMaxWidth(),
+            label = { Text("Answer link or SDP") },
+            minLines = 2,
+            maxLines = 6,
+        )
+        Button(
+            onClick = {
+                onSubmitAnswer(pastedAnswer)
+                pastedAnswer = ""
+            },
+            enabled = pastedAnswer.isNotBlank(),
+        ) {
+            Text("Accept Answer")
+        }
+
+        LeaveButton(onLeave)
+    }
+}
+
+@Composable
+private fun GuestSessionView(
+    state: JamUiState,
+    onShare: (String) -> Unit,
+    onLeave: () -> Unit,
+) {
+    val clipboard = LocalClipboardManager.current
+
+    Column(verticalArrangement = Arrangement.spacedBy(16.dp)) {
+        ParticipantsSection(state.participants)
+
+        val answerLink = state.answerLink
+        if (answerLink == null) {
+            Text(
+                text = "Connecting to the session...",
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        } else {
+            Text(
+                text = "Almost there! Send your answer back to the host:",
+                style = MaterialTheme.typography.titleSmall,
+            )
+            ShareableLinkBox(
+                label = "Answer link",
+                link = answerLink,
+                onCopy = { clipboard.setText(AnnotatedString(answerLink)) },
+                onShare = { onShare(answerLink) },
+            )
+        }
+
+        LeaveButton(onLeave)
+    }
+}
+
+@Composable
+private fun ParticipantsSection(participants: List<dev.krtirtho.spotube.core.jam.JamParticipant>) {
+    Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+        Text(
+            text = "Participants (${participants.size})",
+            style = MaterialTheme.typography.titleSmall,
+        )
+        participants.forEach { participant ->
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                Text(
+                    text = participant.displayName,
+                    style = MaterialTheme.typography.bodyLarge,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier.weight(1f),
+                )
+                if (participant.isHost) {
+                    Text(
+                        text = "Host",
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.primary,
+                    )
+                }
+            }
         }
     }
 }
 
 @Composable
-private fun GuestAnswerView(
-    answer: String,
-    onLeave: () -> Unit,
+private fun ShareableLinkBox(
+    label: String,
+    link: String,
+    onCopy: () -> Unit,
+    onShare: () -> Unit,
 ) {
-    Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
-        Text(
-            text = "You've joined the session. Send this SDP answer back to the host:",
-            style = MaterialTheme.typography.bodyMedium,
-        )
+    val viewModel: JamViewModel = koinViewModel()
+    Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
         SelectionContainer {
             OutlinedTextField(
-                value = answer,
+                value = link,
                 onValueChange = {},
                 readOnly = true,
                 modifier = Modifier.fillMaxWidth(),
-                label = { Text("SDP Answer (copy and send to host)") },
-                minLines = 4,
-                maxLines = 10,
+                label = { Text(label) },
+                minLines = 2,
+                maxLines = 6,
             )
         }
-        Button(onClick = onLeave) {
-            Text("Leave Session")
+        Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            Button(onClick = onCopy) {
+                Text("Copy")
+            }
+            if (viewModel.supportsNativeShare) {
+                OutlinedButton(onClick = onShare) {
+                    Text("Share")
+                }
+            }
         }
     }
 }
+
+@Composable
+private fun LeaveButton(onLeave: () -> Unit) {
+    OutlinedButton(onClick = onLeave) {
+        Text("Leave Session")
+    }
+}

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/modules/jam/JamViewModel.kt

@@ -19,67 +19,205 @@ package dev.krtirtho.spotube.modules.jam
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import dev.krtirtho.spotube.core.audioplayer.AudioPlayerInterface
-import dev.krtirtho.spotube.core.jam.JamMessage
+import dev.krtirtho.spotube.PlatformType
+import dev.krtirtho.spotube.core.deeplink.JamDeepLinkService
+import dev.krtirtho.spotube.core.jam.JamInviteCodec
+import dev.krtirtho.spotube.core.jam.JamInviteLink
 import dev.krtirtho.spotube.core.jam.JamParticipant
 import dev.krtirtho.spotube.core.jam.JamRole
 import dev.krtirtho.spotube.core.jam.JamSessionService
+import dev.krtirtho.spotube.core.share.ShareService
+import dev.krtirtho.spotube.getPlatform
+import dev.krtirtho.spotube.modules.settings.SettingsProvider
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
-import org.koin.core.component.KoinComponent
-import org.koin.core.component.inject
 
-class JamViewModel : ViewModel(), KoinComponent {
-    private val jamSession: JamSessionService by inject()
-    private val audioPlayer: AudioPlayerInterface by inject()
+data class JamUiState(
+    val isActive: Boolean = false,
+    val role: JamRole? = null,
+    val participants: List<JamParticipant> = emptyList(),
+    /** Host: deep link containing this session's SDP offer, ready to share. */
+    val inviteLink: String? = null,
+    /** Guest: deep link containing our SDP answer, to send back to the host. */
+    val answerLink: String? = null,
+    /** Guest: offer received via deep link (or paste), waiting for confirmation. */
+    val incomingHostName: String? = null,
+    val incomingOfferSdp: String? = null,
+    val error: String? = null,
+)
 
-    val role: StateFlow<JamRole?> = jamSession.role
-    val participants: StateFlow<List<JamParticipant>> = jamSession.participants
-    val isActive: StateFlow<Boolean> = jamSession.isActive
+class JamViewModel(
+    private val jamSession: JamSessionService,
+    private val deepLinks: JamDeepLinkService,
+    private val shareService: ShareService,
+    private val settingsProvider: SettingsProvider,
+) : ViewModel() {
 
-    private val _pendingHostOffer = MutableStateFlow<String?>(null)
-    val pendingHostOffer: StateFlow<String?> = _pendingHostOffer.asStateFlow()
+    private val _uiState = MutableStateFlow(JamUiState())
+    val uiState: StateFlow<JamUiState> = _uiState.asStateFlow()
 
-    private val _pendingGuestAnswer = MutableStateFlow<String?>(null)
-    val pendingGuestAnswer: StateFlow<String?> = _pendingGuestAnswer.asStateFlow()
+    val supportsNativeShare: Boolean =
+        getPlatform().type == PlatformType.Android || getPlatform().type == PlatformType.IOS
 
-    private val _error = MutableStateFlow<String?>(null)
-    val error: StateFlow<String?> = _error.asStateFlow()
+    init {
+        viewModelScope.launch {
+            // Mirror live session state into the UI state.
+            jamSession.isActive.collect { active ->
+                _uiState.update {
+                    it.copy(
+                        isActive = active,
+                        role = jamSession.role.value,
+                        participants = jamSession.participants.value,
+                        inviteLink = if (!active) null else it.inviteLink,
+                        answerLink = if (!active) null else it.answerLink,
+                        incomingOfferSdp = if (!active) it.incomingOfferSdp else null,
+                        incomingHostName = if (!active) it.incomingHostName else null,
+                    )
+                }
+            }
+        }
+        viewModelScope.launch {
+            jamSession.participants.collect { participants ->
+                _uiState.update { it.copy(participants = participants) }
+            }
+        }
+        viewModelScope.launch {
+            deepLinks.pendingLink.collect { link ->
+                handleDeepLink(link)
+            }
+        }
+    }
 
     fun createSession() {
         viewModelScope.launch {
-            try {
+            runCatching {
                 val offer = jamSession.createSession()
-                _pendingHostOffer.value = offer
-            } catch (e: Exception) {
-                _error.value = "Failed to create session: ${e.message}"
+                JamInviteCodec.buildHostInvite(localName(), offer)
+            }.onSuccess { link ->
+                _uiState.update { it.copy(inviteLink = link, error = null) }
+            }.onFailure { e ->
+                _uiState.update { it.copy(error = "Failed to create session: ${e.message}") }
             }
         }
     }
 
-    fun joinSession(offer: String) {
+    fun generateNewInvite() {
         viewModelScope.launch {
-            try {
-                val answer = jamSession.joinSession(offer)
-                _pendingGuestAnswer.value = answer
-            } catch (e: Exception) {
-                _error.value = "Failed to join session: ${e.message}"
+            runCatching {
+                val invite = jamSession.generateInvite()
+                JamInviteCodec.buildHostInvite(localName(), invite.sdp)
+            }.onSuccess { link ->
+                _uiState.update { it.copy(inviteLink = link, error = null) }
+            }.onFailure { e ->
+                _uiState.update { it.copy(error = "Failed to generate invite: ${e.message}") }
             }
         }
     }
 
+    fun joinWithIncomingInvite() {
+        val sdp = _uiState.value.incomingOfferSdp ?: return
+        join(sdp)
+    }
+
+    fun joinWithPasted(input: String) {
+        val sdp = JamInviteCodec.extractSdp(input)
+        if (sdp == null) {
+            _uiState.update { it.copy(error = "That doesn't look like a valid jam invite.") }
+            return
+        }
+        join(sdp)
+    }
+
+    /**
+     * Host side: accepts an answer pasted as raw SDP or as a full `spotube://jam/answer` link.
+     */
+    fun submitAnswerPasted(input: String) {
+        when (val parsed = JamInviteCodec.parse(input.trim())) {
+            is JamInviteLink.GuestAnswer -> acceptAnswerInternal(parsed.sdp, parsed.peerName)
+            else -> {
+                val sdp = JamInviteCodec.extractSdp(input)
+                if (sdp == null) {
+                    _uiState.update { it.copy(error = "That doesn't look like a valid SDP answer.") }
+                } else {
+                    acceptAnswerInternal(sdp, "")
+                }
+            }
+        }
+    }
+
+    fun share(text: String) {
+        shareService.share(text, "Spotube Group Jam")
+    }
+
     fun leave() {
         viewModelScope.launch {
             jamSession.leave()
-            _pendingHostOffer.value = null
-            _pendingGuestAnswer.value = null
+            deepLinks.clear()
+            _uiState.update {
+                JamUiState(incomingOfferSdp = it.incomingOfferSdp, incomingHostName = it.incomingHostName)
+            }
         }
     }
 
     fun clearError() {
-        _error.value = null
+        _uiState.update { it.copy(error = null) }
     }
+
+    fun dismissIncomingInvite() {
+        deepLinks.clear()
+        _uiState.update { it.copy(incomingOfferSdp = null, incomingHostName = null) }
+    }
+
+    private fun join(offerSdp: String) {
+        viewModelScope.launch {
+            runCatching {
+                val answer = jamSession.joinSession(offerSdp)
+                JamInviteCodec.buildGuestAnswer(localName(), answer)
+            }.onSuccess { link ->
+                _uiState.update {
+                    it.copy(answerLink = link, incomingOfferSdp = null, incomingHostName = null, error = null)
+                }
+            }.onFailure { e ->
+                _uiState.update { it.copy(error = "Failed to join session: ${e.message}") }
+            }
+        }
+    }
+
+    private fun acceptAnswerInternal(answerSdp: String, peerName: String) {
+        viewModelScope.launch {
+            val accepted = runCatching { jamSession.acceptAnswer(null, answerSdp, peerName) }
+                .getOrDefault(false)
+            if (!accepted) {
+                _uiState.update { it.copy(error = "Couldn't accept that answer — no pending invite matched.") }
+            } else {
+                _uiState.update { it.copy(error = null) }
+            }
+        }
+    }
+
+    private suspend fun handleDeepLink(link: JamInviteLink?) {
+        when (link) {
+            is JamInviteLink.HostInvite -> {
+                if (!jamSession.isActive.value) {
+                    _uiState.update {
+                        it.copy(incomingHostName = link.peerName.ifBlank { "Someone" }, incomingOfferSdp = link.sdp)
+                    }
+                }
+            }
+
+            is JamInviteLink.GuestAnswer -> {
+                if (jamSession.role.value == JamRole.Host) {
+                    acceptAnswerInternal(link.sdp, link.peerName)
+                }
+            }
+
+            null -> Unit
+        }
+    }
+
+    private fun localName(): String =
+        settingsProvider.settingsState.value?.jamParticipantName.orEmpty()
 }

composeApp/src/jvmMain/kotlin/dev/krtirtho/spotube/main.kt

@@ -29,6 +29,7 @@ import androidx.compose.ui.window.rememberWindowState
 import com.sun.jna.Library
 import com.sun.jna.Native
 import dev.krtirtho.spotube.core.di.initKoin
+import dev.krtirtho.spotube.core.deeplink.ExternalUriHandler
 import dev.krtirtho.spotube.core.newpipe.NewPipeDownloader
 import dev.krtirtho.spotube.core.paths.Paths
 import dev.krtirtho.spotube.core.systemtray.SystemTray
@@ -81,9 +82,28 @@ private fun disableWebKitGpuCompositing() {
     LibC.INSTANCE.setenv("WEBKIT_DISABLE_DMABUF_RENDERER", "1", 1)
 }
 
+/**
+ * Routes `spotube://` deep links into [ExternalUriHandler].
+ * macOS delivers them through the open-URI handler; on Linux/Windows they arrive
+ * as command line arguments (scheme registration is handled by the distribution
+ * packaging, e.g. the `.desktop` file's `Exec %u`).
+ */
+private fun handleStartupDeepLinks(args: Array<String>) {
+    runCatching {
+        if (java.awt.Desktop.isDesktopSupported()) {
+            java.awt.Desktop.getDesktop().setOpenURIHandler { event ->
+                ExternalUriHandler.onNewUri(event.uri.toString())
+            }
+        }
+    }
+    args.firstOrNull { it.startsWith("spotube:", ignoreCase = true) }
+        ?.let(ExternalUriHandler::onNewUri)
+}
+
 @OptIn(ExperimentalComposeUiApi::class)
-fun main() {
+fun main(args: Array<String>) {
     disableWebKitGpuCompositing()
+    handleStartupDeepLinks(args)
     FileKit.init(appId = "dev.krtirtho.spotube")
     initKoin()
     NewPipeDownloader.init(KoinPathsProvider.paths)

iosApp/iosApp/Info.plist

@@ -4,6 +4,17 @@
 <dict>
 	<key>CADisableMinimumFrameDurationOnPhone</key>
 	<true/>
+	<key>CFBundleURLTypes</key>
+	<array>
+		<dict>
+			<key>CFBundleURLName</key>
+			<string>dev.krtirtho.spotube</string>
+			<key>CFBundleURLSchemes</key>
+			<array>
+				<string>spotube</string>
+			</array>
+		</dict>
+	</array>
     <key>NSLocalNetworkUsageDescription</key>
     <string>Required to discover local network devices</string>
     <key>NSBonjourServices</key>

iosApp/iosApp/iOSApp.swift

@@ -20,6 +20,9 @@ struct iOSApp: App {
     var body: some Scene {
         WindowGroup {
             ContentView()
+                .onOpenURL { url in
+                    ExternalUriHandler.shared.onNewUri(uri: url.absoluteString)
+                }
         }
     }
 }