feat: implement NIP-B0 Web Bookmarking (kind 39701)

Add support for NIP-B0 web bookmarks with a complete protocol
implementation in Quartz and a full UI in Amethyst for adding,
editing, browsing, and deleting web bookmarks.

Quartz:
- WebBookmarkEvent (kind 39701) as an addressable event
- Tag builder/parser extensions for title, published_at, hashtags
- Registered in EventFactory

Amethyst:
- WebBookmarksScreen with FAB to add, and per-card edit/delete/open
- WebBookmarkEditDialog for add/edit with URL, title, description, tags
- WebBookmarkFeedFilter querying addressable notes by kind + pubkey
- Account.sendWebBookmark() and Account.deleteWebBookmark()
- LocalCache.consume() for WebBookmarkEvent
- Drawer navigation entry with Language icon
- Route.WebBookmarks and navigation registration

https://claude.ai/code/session_01UzfLJttwuJzovtb8HX5F9n

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -213,6 +213,7 @@ import com.vitorpamplona.quartz.nip98HttpAuth.HTTPAuthorizationEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.BaseVoiceEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceReplyEvent
+import com.vitorpamplona.quartz.nipB0WebBookmarks.WebBookmarkEvent
 import com.vitorpamplona.quartz.utils.DualCase
 import com.vitorpamplona.quartz.utils.Log
 import com.vitorpamplona.quartz.utils.containsAny
@@ -1006,6 +1007,31 @@ class Account(
         client.send(event, computeRelayListToBroadcast(event))
     }
 
+    suspend fun sendWebBookmark(
+        url: String,
+        title: String?,
+        description: String,
+        hashtags: List<String> = emptyList(),
+    ) {
+        if (!isWriteable()) return
+
+        val template = WebBookmarkEvent.build(url, title, description, tags = hashtags)
+        val signedEvent = signer.sign(template)
+
+        cache.justConsumeMyOwnEvent(signedEvent)
+        client.send(signedEvent, computeRelayListToBroadcast(signedEvent))
+    }
+
+    suspend fun deleteWebBookmark(event: WebBookmarkEvent) {
+        if (!isWriteable()) return
+
+        val template = DeletionEvent.build(listOf(event))
+        val signedEvent = signer.sign(template)
+
+        cache.justConsumeMyOwnEvent(signedEvent)
+        client.send(signedEvent, computeRelayListToBroadcast(signedEvent))
+    }
+
     fun sendMyPublicAndPrivateOutbox(event: Event?) {
         if (event == null) return
         cache.justConsumeMyOwnEvent(event)

amethyst/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt

@@ -206,6 +206,7 @@ import com.vitorpamplona.quartz.nip96FileStorage.config.FileServersEvent
 import com.vitorpamplona.quartz.nip99Classifieds.ClassifiedsEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceReplyEvent
+import com.vitorpamplona.quartz.nipB0WebBookmarks.WebBookmarkEvent
 import com.vitorpamplona.quartz.nipB7Blossom.BlossomServersEvent
 import com.vitorpamplona.quartz.nipC0CodeSnippets.CodeSnippetEvent
 import com.vitorpamplona.quartz.utils.DualCase
@@ -1433,6 +1434,12 @@ object LocalCache : ILocalCache, ICacheProvider {
         wasVerified: Boolean,
     ) = consumeBaseReplaceable(event, relay, wasVerified)
 
+    fun consume(
+        event: WebBookmarkEvent,
+        relay: NormalizedRelayUrl?,
+        wasVerified: Boolean,
+    ) = consumeBaseReplaceable(event, relay, wasVerified)
+
     private fun consume(
         event: CalendarDateSlotEvent,
         relay: NormalizedRelayUrl?,
@@ -3209,6 +3216,7 @@ object LocalCache : ILocalCache, ICacheProvider {
                 is VideoShortEvent -> consume(event, relay, wasVerified)
                 is VoiceEvent -> consume(event, relay, wasVerified)
                 is VoiceReplyEvent -> consume(event, relay, wasVerified)
+                is WebBookmarkEvent -> consume(event, relay, wasVerified)
                 is WikiNoteEvent -> consume(event, relay, wasVerified)
                 is PaymentTargetsEvent -> consume(event, relay, wasVerified)
                 else -> Log.w("Event Not Supported", "From ${relay?.url}: ${event.toJson()}").let { false }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/feeds/RememberForeverStates.kt

@@ -56,6 +56,8 @@ object ScrollStateKeys {
     const val DISCOVER_CHATS = "DiscoverChatsFeed"
 
     const val SEARCH_SCREEN = "SearchFeed"
+
+    const val WEB_BOOKMARKS = "WebBookmarksFeed"
 }
 
 object PagerStateKeys {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/AppNavigation.kt

@@ -128,6 +128,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.wallet.WalletReceiveScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.wallet.WalletScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.wallet.WalletSendScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.wallet.WalletTransactionsScreen
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.webBookmarks.WebBookmarksScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedOff.AddAccountDialog
 import com.vitorpamplona.amethyst.ui.uriToRoute
 import com.vitorpamplona.quartz.nip01Core.core.Address
@@ -200,6 +201,7 @@ fun AppNavigation(
             composableFromEnd<Route.NamecoinSettings> { NamecoinSettingsScreen(Amethyst.instance.namecoinPrefs, nav) }
             composableFromEnd<Route.OtsSettings> { OtsSettingsScreen(Amethyst.instance.otsPrefs, Amethyst.instance.torPrefs.value, nav) }
             composableFromEnd<Route.Bookmarks> { BookmarkListScreen(accountViewModel, nav) }
+            composableFromEnd<Route.WebBookmarks> { WebBookmarksScreen(accountViewModel, nav) }
             composableFromEnd<Route.Drafts> { DraftListScreen(accountViewModel, nav) }
             composableFromEnd<Route.Settings> { SettingsScreen(accountViewModel, nav) }
             composableFromEnd<Route.UserSettings> { UserSettingsScreen(accountViewModel, nav) }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/drawer/DrawerContent.kt

@@ -51,6 +51,7 @@ import androidx.compose.material.icons.outlined.AccountBalanceWallet
 import androidx.compose.material.icons.outlined.CollectionsBookmark
 import androidx.compose.material.icons.outlined.Drafts
 import androidx.compose.material.icons.outlined.GroupAdd
+import androidx.compose.material.icons.outlined.Language
 import androidx.compose.material.icons.outlined.Settings
 import androidx.compose.material.icons.outlined.Sync
 import androidx.compose.material3.HorizontalDivider
@@ -458,6 +459,14 @@ fun ListContent(
             route = Route.BookmarkGroups,
         )
 
+        NavigationRow(
+            title = R.string.web_bookmarks,
+            icon = Icons.Outlined.Language,
+            tint = MaterialTheme.colorScheme.onBackground,
+            nav = nav,
+            route = Route.WebBookmarks,
+        )
+
         NavigationRow(
             title = R.string.drafts,
             icon = Icons.Outlined.Drafts,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/routes/Routes.kt

@@ -96,6 +96,8 @@ sealed class Route {
         )
     }
 
+    @Serializable object WebBookmarks : Route()
+
     @Serializable object Drafts : Route()
 
     @Serializable object AllSettings : Route()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/AccountFeedContentStates.kt

@@ -45,6 +45,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.notifications.NotificationS
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.notifications.OpenPollsState
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.notifications.dal.NotificationFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.video.dal.VideoFeedFilter
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.webBookmarks.dal.WebBookmarkFeedFilter
 import kotlinx.coroutines.CoroutineScope
 
 class AccountFeedContentStates(
@@ -76,6 +77,8 @@ class AccountFeedContentStates(
 
     val drafts = FeedContentState(DraftEventsFeedFilter(account), scope, LocalCache)
 
+    val webBookmarks = FeedContentState(WebBookmarkFeedFilter(account), scope, LocalCache)
+
     suspend fun init() {
         notificationSummary.initializeSuspend()
     }
@@ -104,6 +107,8 @@ class AccountFeedContentStates(
         notificationSummary.invalidateInsertData(newNotes)
 
         drafts.updateFeedWith(newNotes)
+
+        webBookmarks.updateFeedWith(newNotes)
     }
 
     fun deleteNotes(newNotes: Set<Note>) {
@@ -130,6 +135,8 @@ class AccountFeedContentStates(
         notificationSummary.invalidateInsertData(newNotes)
 
         drafts.deleteFromFeed(newNotes)
+
+        webBookmarks.deleteFromFeed(newNotes)
     }
 
     fun destroy() {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/relays/RelayInformationScreen.kt

@@ -269,6 +269,7 @@ import com.vitorpamplona.quartz.nip98HttpAuth.HTTPAuthorizationEvent
 import com.vitorpamplona.quartz.nip99Classifieds.ClassifiedsEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceReplyEvent
+import com.vitorpamplona.quartz.nipB0WebBookmarks.WebBookmarkEvent
 import com.vitorpamplona.quartz.nipB7Blossom.BlossomAuthorizationEvent
 import com.vitorpamplona.quartz.nipB7Blossom.BlossomServersEvent
 import com.vitorpamplona.quartz.utils.TimeUtils
@@ -658,6 +659,7 @@ private fun kindDisplayName(kind: Int): Int =
         VideoShortEvent.KIND -> R.string.kind_shorts
         VoiceEvent.KIND -> R.string.kind_voice_msg
         VoiceReplyEvent.KIND -> R.string.kind_voice_reply
+        WebBookmarkEvent.KIND -> R.string.kind_web_bookmark
         WikiNoteEvent.KIND -> R.string.kind_wiki
         else -> -1
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/webBookmarks/WebBookmarksScreen.kt

@@ -0,0 +1,398 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.screen.loggedIn.webBookmarks
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Edit
+import androidx.compose.material.icons.filled.OpenInBrowser
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalUriHandler
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.commons.ui.feeds.FeedContentState
+import com.vitorpamplona.amethyst.commons.ui.feeds.FeedState
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.ui.feeds.RefresheableBox
+import com.vitorpamplona.amethyst.ui.feeds.RenderFeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.ScrollStateKeys
+import com.vitorpamplona.amethyst.ui.feeds.WatchLifecycleAndUpdateModel
+import com.vitorpamplona.amethyst.ui.layouts.DisappearingScaffold
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.topbars.ShorterTopAppBar
+import com.vitorpamplona.amethyst.ui.note.ArrowBackIcon
+import com.vitorpamplona.amethyst.ui.screen.SaveableFeedState
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.amethyst.ui.theme.DividerThickness
+import com.vitorpamplona.amethyst.ui.theme.FeedPadding
+import com.vitorpamplona.quartz.nipB0WebBookmarks.WebBookmarkEvent
+
+@Composable
+fun WebBookmarksScreen(
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    RenderWebBookmarksScreen(accountViewModel.feedStates.webBookmarks, accountViewModel, nav)
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun RenderWebBookmarksScreen(
+    feedState: FeedContentState,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    WatchLifecycleAndUpdateModel(feedState)
+
+    var showAddDialog by remember { mutableStateOf(false) }
+
+    if (showAddDialog) {
+        WebBookmarkEditDialog(
+            onDismiss = { showAddDialog = false },
+            onSave = { url, title, description, tags ->
+                accountViewModel.launchSigner {
+                    accountViewModel.account.sendWebBookmark(url, title, description, tags)
+                }
+                showAddDialog = false
+            },
+        )
+    }
+
+    DisappearingScaffold(
+        isInvertedLayout = false,
+        topBar = {
+            ShorterTopAppBar(
+                title = {
+                    Text(text = stringRes(id = R.string.web_bookmarks))
+                },
+                navigationIcon = {
+                    IconButton(onClick = nav::popBack) {
+                        ArrowBackIcon()
+                    }
+                },
+            )
+        },
+        floatingButton = {
+            FloatingActionButton(
+                onClick = { showAddDialog = true },
+            ) {
+                Icon(
+                    imageVector = Icons.Default.Add,
+                    contentDescription = stringResource(R.string.web_bookmark_add_title),
+                )
+            }
+        },
+        accountViewModel = accountViewModel,
+    ) {
+        Column(Modifier.padding(it).fillMaxHeight()) {
+            RefresheableBox(feedState) {
+                SaveableFeedState(feedState, ScrollStateKeys.WEB_BOOKMARKS) { listState ->
+                    RenderFeedContentState(
+                        feedContentState = feedState,
+                        accountViewModel = accountViewModel,
+                        listState = listState,
+                        nav = nav,
+                        routeForLastRead = null,
+                        onLoaded = { WebBookmarksFeedLoaded(it, listState, accountViewModel, nav) },
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun WebBookmarksFeedLoaded(
+    loaded: FeedState.Loaded,
+    listState: LazyListState,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val items by loaded.feed.collectAsStateWithLifecycle()
+
+    LazyColumn(
+        contentPadding = FeedPadding,
+        state = listState,
+    ) {
+        itemsIndexed(items.list, key = { _, item -> item.idHex }) { _, item ->
+            WebBookmarkCard(item, accountViewModel, nav)
+
+            HorizontalDivider(thickness = DividerThickness)
+        }
+    }
+}
+
+@Composable
+private fun WebBookmarkCard(
+    note: Note,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val event = note.event as? WebBookmarkEvent ?: return
+    val uriHandler = LocalUriHandler.current
+
+    var showEditDialog by remember { mutableStateOf(false) }
+    var showDeleteDialog by remember { mutableStateOf(false) }
+
+    if (showEditDialog) {
+        WebBookmarkEditDialog(
+            initialUrl = event.url(),
+            initialTitle = event.title() ?: "",
+            initialDescription = event.description(),
+            initialTags = event.hashtags().joinToString(", "),
+            onDismiss = { showEditDialog = false },
+            onSave = { url, title, description, tags ->
+                accountViewModel.launchSigner {
+                    accountViewModel.account.sendWebBookmark(url, title, description, tags)
+                }
+                showEditDialog = false
+            },
+        )
+    }
+
+    if (showDeleteDialog) {
+        AlertDialog(
+            onDismissRequest = { showDeleteDialog = false },
+            title = { Text(stringResource(R.string.web_bookmark_delete)) },
+            text = { Text(stringResource(R.string.web_bookmark_delete_confirm)) },
+            confirmButton = {
+                TextButton(onClick = {
+                    accountViewModel.launchSigner {
+                        accountViewModel.account.deleteWebBookmark(event)
+                    }
+                    showDeleteDialog = false
+                }) {
+                    Text(stringResource(R.string.yes))
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { showDeleteDialog = false }) {
+                    Text(stringResource(R.string.no))
+                }
+            },
+        )
+    }
+
+    Column(
+        modifier =
+            Modifier
+                .fillMaxWidth()
+                .clickable { uriHandler.openUri(event.url()) }
+                .padding(16.dp),
+    ) {
+        Row(
+            modifier = Modifier.fillMaxWidth(),
+            horizontalArrangement = Arrangement.SpaceBetween,
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Column(modifier = Modifier.weight(1f)) {
+                Text(
+                    text = event.title() ?: event.url(),
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.Bold,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+
+                Text(
+                    text = event.url(),
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.primary,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+
+            Row {
+                IconButton(onClick = { uriHandler.openUri(event.url()) }) {
+                    Icon(
+                        imageVector = Icons.Default.OpenInBrowser,
+                        contentDescription = stringResource(R.string.web_bookmark_open_url),
+                    )
+                }
+                IconButton(onClick = { showEditDialog = true }) {
+                    Icon(
+                        imageVector = Icons.Default.Edit,
+                        contentDescription = stringResource(R.string.web_bookmark_edit_title),
+                    )
+                }
+                IconButton(onClick = { showDeleteDialog = true }) {
+                    Icon(
+                        imageVector = Icons.Default.Delete,
+                        contentDescription = stringResource(R.string.web_bookmark_delete),
+                        tint = MaterialTheme.colorScheme.error,
+                    )
+                }
+            }
+        }
+
+        if (event.description().isNotBlank()) {
+            Spacer(modifier = Modifier.height(4.dp))
+            Text(
+                text = event.description(),
+                style = MaterialTheme.typography.bodyMedium,
+                maxLines = 3,
+                overflow = TextOverflow.Ellipsis,
+            )
+        }
+
+        val tags = event.hashtags()
+        if (tags.isNotEmpty()) {
+            Spacer(modifier = Modifier.height(4.dp))
+            Row {
+                tags.forEach { tag ->
+                    Text(
+                        text = "#$tag",
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.secondary,
+                        modifier = Modifier.padding(end = 8.dp),
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun WebBookmarkEditDialog(
+    initialUrl: String = "",
+    initialTitle: String = "",
+    initialDescription: String = "",
+    initialTags: String = "",
+    onDismiss: () -> Unit,
+    onSave: (url: String, title: String?, description: String, tags: List<String>) -> Unit,
+) {
+    var url by remember { mutableStateOf(initialUrl) }
+    var title by remember { mutableStateOf(initialTitle) }
+    var description by remember { mutableStateOf(initialDescription) }
+    var tags by remember { mutableStateOf(initialTags) }
+
+    val isEditing = initialUrl.isNotEmpty()
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = {
+            Text(
+                stringResource(
+                    if (isEditing) R.string.web_bookmark_edit_title else R.string.web_bookmark_add_title,
+                ),
+            )
+        },
+        text = {
+            Column {
+                OutlinedTextField(
+                    value = url,
+                    onValueChange = { url = it },
+                    label = { Text(stringResource(R.string.web_bookmark_url_label)) },
+                    placeholder = { Text(stringResource(R.string.web_bookmark_url_placeholder)) },
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth(),
+                )
+
+                Spacer(modifier = Modifier.height(8.dp))
+
+                OutlinedTextField(
+                    value = title,
+                    onValueChange = { title = it },
+                    label = { Text(stringResource(R.string.web_bookmark_title_label)) },
+                    placeholder = { Text(stringResource(R.string.web_bookmark_title_placeholder)) },
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth(),
+                )
+
+                Spacer(modifier = Modifier.height(8.dp))
+
+                OutlinedTextField(
+                    value = description,
+                    onValueChange = { description = it },
+                    label = { Text(stringResource(R.string.web_bookmark_description_label)) },
+                    placeholder = { Text(stringResource(R.string.web_bookmark_description_placeholder)) },
+                    maxLines = 3,
+                    modifier = Modifier.fillMaxWidth(),
+                )
+
+                Spacer(modifier = Modifier.height(8.dp))
+
+                OutlinedTextField(
+                    value = tags,
+                    onValueChange = { tags = it },
+                    label = { Text(stringResource(R.string.web_bookmark_tags_label)) },
+                    placeholder = { Text(stringResource(R.string.web_bookmark_tags_placeholder)) },
+                    singleLine = true,
+                    modifier = Modifier.fillMaxWidth(),
+                )
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    if (url.isNotBlank()) {
+                        val normalizedUrl = if (!url.startsWith("http")) "https://$url" else url
+                        val tagList = tags.split(",").map { it.trim() }.filter { it.isNotEmpty() }
+                        onSave(normalizedUrl, title.ifBlank { null }, description, tagList)
+                    }
+                },
+                enabled = url.isNotBlank(),
+            ) {
+                Text(stringResource(R.string.web_bookmark_save))
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text(stringResource(R.string.cancel))
+            }
+        },
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/webBookmarks/dal/WebBookmarkFeedFilter.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.screen.loggedIn.webBookmarks.dal
+
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.model.filterIntoSet
+import com.vitorpamplona.amethyst.ui.dal.AdditiveFeedFilter
+import com.vitorpamplona.amethyst.ui.dal.DefaultFeedOrder
+import com.vitorpamplona.quartz.nipB0WebBookmarks.WebBookmarkEvent
+
+class WebBookmarkFeedFilter(
+    val account: Account,
+) : AdditiveFeedFilter<Note>() {
+    override fun feedKey(): String = account.userProfile().pubkeyHex + "/webBookmarks"
+
+    override fun applyFilter(newItems: Set<Note>): Set<Note> =
+        newItems.filterTo(HashSet()) {
+            acceptableEvent(it)
+        }
+
+    override fun feed(): List<Note> {
+        val bookmarks =
+            LocalCache.addressables.filterIntoSet(WebBookmarkEvent.KIND, account.userProfile().pubkeyHex) { _, note ->
+                acceptableEvent(note)
+            }
+
+        return sort(bookmarks)
+    }
+
+    fun acceptableEvent(it: Note): Boolean {
+        val noteEvent = it.event
+        return noteEvent is WebBookmarkEvent && noteEvent.pubKey == account.userProfile().pubkeyHex
+    }
+
+    override fun sort(items: Set<Note>): List<Note> = items.sortedWith(DefaultFeedOrder)
+}

amethyst/src/main/res/values/strings.xml

@@ -1818,6 +1818,7 @@
     <string name="kind_shorts">Shorts</string>
     <string name="kind_voice_msg">Voice Msg</string>
     <string name="kind_voice_reply">Voice Reply</string>
+    <string name="kind_web_bookmark">Web Bookmark</string>
     <string name="kind_wiki">Wiki</string>
     <string name="start_with_a_great_feed_by_following_the_same_people_as_someone_you_trust">Start with a great feed by following the same people as someone you trust.</string>
     <string name="import_follow_list">Import Follow List</string>
@@ -1936,4 +1937,20 @@
     <string name="event_sync_date_filter_all_time">All time</string>
     <string name="event_sync_date_filter_last_sync">Last sync: %1$s</string>
     <string name="event_sync_date_filter_since_last_sync">Since Last Sync</string>
+    <string name="web_bookmarks">Web Bookmarks</string>
+    <string name="web_bookmarks_empty">No web bookmarks yet. Tap + to add one.</string>
+    <string name="web_bookmark_add_title">Add Web Bookmark</string>
+    <string name="web_bookmark_edit_title">Edit Web Bookmark</string>
+    <string name="web_bookmark_url_label">URL</string>
+    <string name="web_bookmark_url_placeholder">https://example.com</string>
+    <string name="web_bookmark_title_label">Title</string>
+    <string name="web_bookmark_title_placeholder">Bookmark title</string>
+    <string name="web_bookmark_description_label">Description</string>
+    <string name="web_bookmark_description_placeholder">A short description</string>
+    <string name="web_bookmark_tags_label">Tags (comma-separated)</string>
+    <string name="web_bookmark_tags_placeholder">nostr, tech, blog</string>
+    <string name="web_bookmark_save">Save</string>
+    <string name="web_bookmark_delete">Delete</string>
+    <string name="web_bookmark_delete_confirm">Delete this web bookmark?</string>
+    <string name="web_bookmark_open_url">Open URL</string>
 </resources>

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nipB0WebBookmarks/TagArrayBuilderExt.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nipB0WebBookmarks
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip23LongContent.tags.PublishedAtTag
+import com.vitorpamplona.quartz.nip23LongContent.tags.TitleTag
+
+fun TagArrayBuilder<WebBookmarkEvent>.title(title: String) = addUnique(TitleTag.assemble(title))
+
+fun TagArrayBuilder<WebBookmarkEvent>.publishedAt(timestamp: Long) = addUnique(PublishedAtTag.assemble(timestamp))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nipB0WebBookmarks/TagArrayExt.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nipB0WebBookmarks
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip01Core.tags.hashtags.hashtags
+import com.vitorpamplona.quartz.nip23LongContent.tags.PublishedAtTag
+import com.vitorpamplona.quartz.nip23LongContent.tags.TitleTag
+
+fun TagArray.webBookmarkTitle() = firstNotNullOfOrNull(TitleTag::parse)
+
+fun TagArray.webBookmarkPublishedAt() = firstNotNullOfOrNull(PublishedAtTag::parse)
+
+fun TagArray.webBookmarkHashtags() = hashtags()

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nipB0WebBookmarks/WebBookmarkEvent.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nipB0WebBookmarks
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
+import com.vitorpamplona.quartz.nip01Core.tags.hashtags.hashtags
+import com.vitorpamplona.quartz.nip22Comments.RootScope
+import com.vitorpamplona.quartz.nip23LongContent.tags.PublishedAtTag
+import com.vitorpamplona.quartz.nip23LongContent.tags.TitleTag
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class WebBookmarkEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: TagArray,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig),
+    RootScope {
+    fun url(): String {
+        val dTagValue = dTag()
+        return if (dTagValue.isNotEmpty()) "https://$dTagValue" else ""
+    }
+
+    fun title() = tags.firstNotNullOfOrNull(TitleTag::parse)
+
+    fun publishedAt() = tags.firstNotNullOfOrNull(PublishedAtTag::parse)
+
+    fun hashtags() = tags.hashtags()
+
+    fun description() = content
+
+    companion object {
+        const val KIND = 39701
+        const val ALT_DESCRIPTION = "Web Bookmark"
+
+        fun urlToDTag(url: String): String =
+            url
+                .removePrefix("https://")
+                .removePrefix("http://")
+                .trimEnd('/')
+
+        fun build(
+            url: String,
+            bookmarkTitle: String?,
+            description: String,
+            tags: List<String> = emptyList(),
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<WebBookmarkEvent>.() -> Unit = {},
+        ) = eventTemplate<WebBookmarkEvent>(KIND, description, createdAt) {
+            dTag(urlToDTag(url))
+            alt(ALT_DESCRIPTION)
+            bookmarkTitle?.let { title(it) }
+            publishedAt(createdAt)
+            hashtags(tags)
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt

@@ -156,6 +156,7 @@ import com.vitorpamplona.quartz.nip98HttpAuth.HTTPAuthorizationEvent
 import com.vitorpamplona.quartz.nip99Classifieds.ClassifiedsEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.VoiceReplyEvent
+import com.vitorpamplona.quartz.nipB0WebBookmarks.WebBookmarkEvent
 import com.vitorpamplona.quartz.nipB7Blossom.BlossomAuthorizationEvent
 import com.vitorpamplona.quartz.nipB7Blossom.BlossomServersEvent
 import com.vitorpamplona.quartz.nipC0CodeSnippets.CodeSnippetEvent
@@ -321,6 +322,7 @@ class EventFactory {
                 VideoShortEvent.KIND -> VideoShortEvent(id, pubKey, createdAt, tags, content, sig)
                 VoiceEvent.KIND -> VoiceEvent(id, pubKey, createdAt, tags, content, sig)
                 VoiceReplyEvent.KIND -> VoiceReplyEvent(id, pubKey, createdAt, tags, content, sig)
+                WebBookmarkEvent.KIND -> WebBookmarkEvent(id, pubKey, createdAt, tags, content, sig)
                 WikiNoteEvent.KIND -> WikiNoteEvent(id, pubKey, createdAt, tags, content, sig)
                 else -> factories[kind]?.build(id, pubKey, createdAt, tags, content, sig) ?: Event(id, pubKey, createdAt, kind, tags, content, sig)
             } as T