diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fd8d94e..f3d5199 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,9 +32,11 @@ jobs:
           distribution: temurin
           java-version: 21
       - uses: gradle/actions/setup-gradle@v5
-      # Lint first: a lint failure should not cost a full APK build.
+      # Lint and tests first: neither should cost a full APK build.
       - name: Lint
         run: ./gradlew :app:lintDebug
+      - name: Unit tests
+        run: ./gradlew :app:testDebugUnitTest
       - name: Build debug APK
         run: ./gradlew :app:assembleDebug
       # Unsigned, but proves the R8/minify path before launch week does.
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 579b603..0bc7d7e 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -83,4 +83,9 @@ dependencies {
     implementation(libs.navigation3.ui)
     implementation(libs.kotlinx.serialization.json)
     implementation(libs.spoo.sdk)
+
+    testImplementation(libs.junit)
+    testImplementation(libs.kotlin.test)
+    testImplementation(libs.kotlinx.coroutines.test)
+    testImplementation(libs.turbine)
 }
diff --git a/app/src/main/kotlin/me/spoo/android/data/Links.kt b/app/src/main/kotlin/me/spoo/android/data/Links.kt
index 2a768a2..aa0168f 100644
--- a/app/src/main/kotlin/me/spoo/android/data/Links.kt
+++ b/app/src/main/kotlin/me/spoo/android/data/Links.kt
@@ -23,6 +23,8 @@ data class SpooLink(
     /** Whether known bots are kept from following the link. */
     val blockBots: Boolean = false,
     val createdAtMillis: Long? = null,
+    /** Most recent click, when the link has ever been clicked. */
+    val lastClickMillis: Long? = null,
 ) {
     val shortUrl: String get() = "spoo.me/$shortCode"
     val active: Boolean get() = status == LinkUiStatus.Active
@@ -30,7 +32,7 @@ data class SpooLink(
 }
 
 /** Sort order for the links list. */
-enum class LinkSort { Recent, Clicks }
+enum class LinkSort { Recent, Clicks, LastClick }
 
 /**
  * The server-side view of the links list. Search, sort and filters ride
@@ -111,6 +113,9 @@ data class EmojiChoice(
     val keywords: List<String> = emptyList(),
 )
 
+/** Why an alias can't be used, or [Free] when it can. */
+enum class AliasStatus { Free, Taken, Reserved, Invalid, Unknown }
+
 /** The accepted emoji catalogue plus the alias-length policy. */
 data class EmojiCatalog(
     val maxGraphemes: Int,
@@ -118,7 +123,17 @@ data class EmojiCatalog(
 )
 
 /** A dimension the stats screens can filter by. */
-enum class StatsDim { Country, Browser, Os, Referrer }
+enum class StatsDim(
+    /** Human label; the enum name alone reads UTMSOURCE. */
+    val display: String,
+) {
+    Country("Country"),
+    Browser("Browser"),
+    Os("OS"),
+    Referrer("Referrer"),
+    Device("Device"),
+    UtmSource("UTM source"),
+}
 
 /** The countable thing a stats query asks for. */
 enum class StatsMetric { Clicks, UniqueClicks }
@@ -143,6 +158,8 @@ data class LinkStats(
     val browsers: List<Slice>,
     val os: List<Slice>,
     val referrers: List<Slice>,
+    val devices: List<Slice> = emptyList(),
+    val utmSources: List<Slice> = emptyList(),
 ) {
     data class Slice(
         val label: String,
diff --git a/app/src/main/kotlin/me/spoo/android/data/LinksRepository.kt b/app/src/main/kotlin/me/spoo/android/data/LinksRepository.kt
index 3e37cd7..caa88ef 100644
--- a/app/src/main/kotlin/me/spoo/android/data/LinksRepository.kt
+++ b/app/src/main/kotlin/me/spoo/android/data/LinksRepository.kt
@@ -58,4 +58,7 @@ interface LinksRepository {
 
     /** The accepted emoji-alias catalogue; changes rarely, cached upstream. */
     suspend fun emojiCatalog(): EmojiCatalog
+
+    /** Whether [alias] can be claimed, and when not, why. */
+    suspend fun aliasStatus(alias: String): AliasStatus
 }
diff --git a/app/src/main/kotlin/me/spoo/android/data/MockLinksRepository.kt b/app/src/main/kotlin/me/spoo/android/data/MockLinksRepository.kt
index 27630b2..d542da6 100644
--- a/app/src/main/kotlin/me/spoo/android/data/MockLinksRepository.kt
+++ b/app/src/main/kotlin/me/spoo/android/data/MockLinksRepository.kt
@@ -113,6 +113,7 @@ class MockLinksRepository : LinksRepository {
                     when (query.sort) {
                         LinkSort.Recent -> list
                         LinkSort.Clicks -> list.sortedByDescending { it.totalClicks }
+                        LinkSort.LastClick -> list.sortedByDescending { it.lastClickMillis ?: Long.MIN_VALUE }
                     }
                 }
         _links.value = full.take(visible)
@@ -271,6 +272,19 @@ class MockLinksRepository : LinksRepository {
         return EmojiCatalog(maxGraphemes = 15, entries = MOCK_EMOJI)
     }
 
+    override suspend fun aliasStatus(alias: String): AliasStatus {
+        delay(250)
+        // Aliases are case-sensitive server-side; RESERVED_ALIASES stands in
+        // for the platform's reserved set so the copy path is demoable.
+        return when {
+            alias.lowercase() in RESERVED_ALIASES -> AliasStatus.Reserved
+            !alias.any(Char::isLetterOrDigit) && alias.isNotEmpty() -> AliasStatus.Free
+            alias.length < 3 && alias.all { it.code < 128 } -> AliasStatus.Invalid
+            all.value.any { it.shortCode == alias } -> AliasStatus.Taken
+            else -> AliasStatus.Free
+        }
+    }
+
     private val statsCache = mutableMapOf<String, LinkStats>()
 
     override fun cachedStats(
@@ -332,6 +346,8 @@ class MockLinksRepository : LinksRepository {
         share(REFERRERS, params.filters[StatsDim.Referrer])?.let { total *= it }
         share(BROWSERS, params.filters[StatsDim.Browser])?.let { total *= it }
         share(OSES, params.filters[StatsDim.Os])?.let { total *= it }
+        share(DEVICES, params.filters[StatsDim.Device])?.let { total *= it }
+        share(UTM_SOURCES, params.filters[StatsDim.UtmSource])?.let { total *= it }
 
         val points = days.coerceIn(7, 120)
         val weights =
@@ -365,6 +381,8 @@ class MockLinksRepository : LinksRepository {
             browsers = slices(BROWSERS, params.filters[StatsDim.Browser]),
             os = slices(OSES, params.filters[StatsDim.Os]),
             referrers = slices(REFERRERS, params.filters[StatsDim.Referrer]),
+            devices = slices(DEVICES, params.filters[StatsDim.Device]),
+            utmSources = slices(UTM_SOURCES, params.filters[StatsDim.UtmSource]),
         )
     }
 
@@ -390,6 +408,16 @@ class MockLinksRepository : LinksRepository {
         maxClicks = maxClicks,
         expireAtMillis = expiresInDays?.let { System.currentTimeMillis() + it * 86_400_000L },
         createdAtMillis = System.currentTimeMillis() - ageDays * 86_400_000L,
+        // Busier links were clicked more recently, always inside the
+        // link's own lifetime; deterministic per link.
+        lastClickMillis =
+            if (clicks == 0) {
+                null
+            } else {
+                val lifetime = ageDays.coerceAtLeast(1) * 86_400_000L
+                val idle = lifetime / (1 + clicks / 500).coerceAtMost(24)
+                System.currentTimeMillis() - (idle + id.hashCode().mod(6) * 3_600_000L).coerceAtMost(lifetime)
+            },
     )
 
     private companion object {
@@ -439,6 +467,24 @@ class MockLinksRepository : LinksRepository {
                 "Linux" to 0.09f,
             )
 
+        val DEVICES =
+            listOf(
+                "mobile" to 0.58f,
+                "desktop" to 0.33f,
+                "tablet" to 0.07f,
+                "unknown" to 0.02f,
+            )
+        val UTM_SOURCES =
+            listOf(
+                "(none)" to 0.61f,
+                "newsletter" to 0.14f,
+                "twitter" to 0.11f,
+                "producthunt" to 0.08f,
+                "discord" to 0.06f,
+            )
+
+        val RESERVED_ALIASES = setOf("api", "login", "signup", "admin", "stats", "dashboard")
+
         // Offline stand-in for /api/v1/emoji-set: real groups, tiny slices.
         val MOCK_EMOJI =
             listOf(
diff --git a/app/src/main/kotlin/me/spoo/android/data/SdkLinksRepository.kt b/app/src/main/kotlin/me/spoo/android/data/SdkLinksRepository.kt
index 0f4b4c1..47601c6 100644
--- a/app/src/main/kotlin/me/spoo/android/data/SdkLinksRepository.kt
+++ b/app/src/main/kotlin/me/spoo/android/data/SdkLinksRepository.kt
@@ -9,6 +9,7 @@ import kotlinx.serialization.json.contentOrNull
 import kotlinx.serialization.json.jsonPrimitive
 import kotlinx.serialization.json.longOrNull
 import me.spoo.AccountStatsRequest
+import me.spoo.AliasIssue
 import me.spoo.AliasKind
 import me.spoo.AuthenticationException
 import me.spoo.Dimension
@@ -90,6 +91,7 @@ class SdkLinksRepository(
                 when (sort) {
                     LinkSort.Recent -> SortBy.CREATED_AT
                     LinkSort.Clicks -> SortBy.TOTAL_CLICKS
+                    LinkSort.LastClick -> SortBy.LAST_CLICK
                 },
             sortOrder = SortOrder.DESCENDING,
             // The typed status param only speaks active/inactive; expired and
@@ -231,6 +233,18 @@ class SdkLinksRepository(
     // changes; the set is public and near-static, so one fetch per process.
     private var cachedCatalog: EmojiCatalog? = null
 
+    override suspend fun aliasStatus(alias: String): AliasStatus =
+        withSession {
+            val check = clientProvider().links.checkAlias(alias)
+            when {
+                check.available -> AliasStatus.Free
+                check.reason == AliasIssue.TAKEN -> AliasStatus.Taken
+                check.reason == AliasIssue.RESERVED -> AliasStatus.Reserved
+                check.reason != null -> AliasStatus.Invalid
+                else -> AliasStatus.Unknown
+            }
+        }
+
     override suspend fun emojiCatalog(): EmojiCatalog {
         cachedCatalog?.let { return it }
         val set = clientProvider().emoji.set()
@@ -303,6 +317,8 @@ class SdkLinksRepository(
                     Dimension.BROWSER,
                     Dimension.OS,
                     Dimension.REFERRER,
+                    Dimension.DEVICE,
+                    Dimension.UTM_SOURCE,
                 ),
             metrics =
                 listOf(
@@ -318,6 +334,8 @@ class SdkLinksRepository(
                         StatsDim.Browser -> FilterDimension.BROWSER
                         StatsDim.Os -> FilterDimension.OS
                         StatsDim.Referrer -> FilterDimension.REFERRER
+                        StatsDim.Device -> FilterDimension.DEVICE
+                        StatsDim.UtmSource -> FilterDimension.UTM_SOURCE
                     } to values.toList()
                 },
         )
@@ -332,6 +350,8 @@ class SdkLinksRepository(
         browsers = slices("${metricKey}_by_browser", metricKey),
         os = slices("${metricKey}_by_os", metricKey),
         referrers = slices("${metricKey}_by_referrer", metricKey),
+        devices = slices("${metricKey}_by_device", metricKey),
+        utmSources = slices("${metricKey}_by_utm_source", metricKey),
     )
 
     private fun Map<String, List<JsonObject>>.slices(
@@ -380,6 +400,7 @@ class SdkLinksRepository(
             privateStats = privateStats ?: false,
             blockBots = blockBots ?: false,
             createdAtMillis = createdAt?.toEpochMilliseconds(),
+            lastClickMillis = lastClick?.toEpochMilliseconds(),
         )
 
     private fun Instant.toDayLabel(): String = SimpleDateFormat("MMM d", Locale.US).format(Date(toEpochMilliseconds()))
diff --git a/app/src/main/kotlin/me/spoo/android/data/SwitchingLinksRepository.kt b/app/src/main/kotlin/me/spoo/android/data/SwitchingLinksRepository.kt
index 5e4f9fe..6adc0e3 100644
--- a/app/src/main/kotlin/me/spoo/android/data/SwitchingLinksRepository.kt
+++ b/app/src/main/kotlin/me/spoo/android/data/SwitchingLinksRepository.kt
@@ -81,4 +81,6 @@ class SwitchingLinksRepository(
     ) = active.cachedStats(shortCode, params)
 
     override suspend fun emojiCatalog() = active.emojiCatalog()
+
+    override suspend fun aliasStatus(alias: String) = active.aliasStatus(alias)
 }
diff --git a/app/src/main/kotlin/me/spoo/android/ui/components/CreateLinkSheet.kt b/app/src/main/kotlin/me/spoo/android/ui/components/CreateLinkSheet.kt
index 5f8dd9c..767ad6a 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/components/CreateLinkSheet.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/components/CreateLinkSheet.kt
@@ -54,6 +54,7 @@ import androidx.compose.material3.TooltipDefaults
 import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.material3.rememberTooltipState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -64,6 +65,8 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalClipboardManager
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.text.input.PasswordVisualTransformation
@@ -73,6 +76,7 @@ import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import kotlinx.coroutines.launch
+import me.spoo.android.data.AliasStatus
 import me.spoo.android.data.CreateLinkRequest
 import me.spoo.android.data.EmojiCatalog
 import me.spoo.android.data.ErrorField
@@ -90,6 +94,8 @@ fun CreateLinkSheet(
     initialUrl: String?,
     state: CreateState,
     emojiCatalog: EmojiCatalog?,
+    aliasStatus: AliasStatus,
+    onAliasChanged: (String) -> Unit,
     onEmojiMode: () -> Unit,
     onSubmit: (CreateLinkRequest) -> Unit,
     onDismiss: () -> Unit,
@@ -134,6 +140,8 @@ fun CreateLinkSheet(
                         submitting = state is CreateState.Submitting,
                         error = (state as? CreateState.Failed)?.error,
                         emojiCatalog = emojiCatalog,
+                        aliasStatus = aliasStatus,
+                        onAliasChanged = onAliasChanged,
                         onEmojiMode = {
                             onEmojiMode()
                             // The picker deserves the room: pop the sheet open.
@@ -155,6 +163,8 @@ private fun FormPhase(
     submitting: Boolean,
     error: FriendlyError?,
     emojiCatalog: EmojiCatalog?,
+    aliasStatus: AliasStatus,
+    onAliasChanged: (String) -> Unit,
     onEmojiMode: () -> Unit,
     onSubmit: (CreateLinkRequest) -> Unit,
 ) {
@@ -175,6 +185,19 @@ private fun FormPhase(
     val emojiCount = emojiPicks.codePointCount(0, emojiPicks.length)
     val emojiMax = emojiCatalog?.maxGraphemes ?: Int.MAX_VALUE
 
+    // Live availability: report the effective alias upstream, debounced
+    // and checked in the view model; "taken" comes back as [aliasTaken].
+    val effectiveAlias = if (emojiAlias) emojiPicks else alias.trim()
+    LaunchedEffect(effectiveAlias) { onAliasChanged(effectiveAlias) }
+    val aliasBlocked = aliasStatus != AliasStatus.Free && aliasStatus != AliasStatus.Unknown
+    val aliasMessage =
+        when (aliasStatus) {
+            AliasStatus.Taken -> "Already taken"
+            AliasStatus.Reserved -> "Reserved by spoo.me"
+            AliasStatus.Invalid -> "Not a usable alias"
+            else -> null
+        }
+
     // Prevention first, server as backstop: local checks gate the button;
     // whatever still comes back lands on the field the server names.
     val urlOk = isLikelyUrl(url)
@@ -216,15 +239,40 @@ private fun FormPhase(
         // icon swaps back. In emoji mode the field is a read-only composed
         // display, so an invalid alias can't be typed.
         OutlinedTextField(
-            value = if (emojiAlias) emojiPicks.emojiPresentationAll() else alias,
+            // Emoji live in the prefix slot as Fluent artwork. The text slot
+            // carries a zero-width space when picks exist: an empty unfocused
+            // field hides its prefix and floats the label back down.
+            value =
+                when {
+                    !emojiAlias -> alias
+                    emojiPicks.isEmpty() -> ""
+                    else -> "\u200B"
+                },
             // The API's alias charset, enforced at the keyboard: no error to show.
             onValueChange = { if (!emojiAlias) alias = it.filter(::isAliasChar) },
             modifier = Modifier.fillMaxWidth(),
             readOnly = emojiAlias,
             label = { Text(if (emojiAlias) "Emoji alias" else "Alias") },
-            placeholder = { Text("Random if empty", maxLines = 1) },
-            prefix = { Text("spoo.me/") },
-            isError = error?.field == ErrorField.Alias,
+            placeholder =
+                if (emojiAlias && emojiPicks.isNotEmpty()) {
+                    null
+                } else {
+                    { Text("Random if empty", maxLines = 1) }
+                },
+            prefix = {
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    Text("spoo.me/")
+                    if (emojiAlias && emojiPicks.isNotEmpty()) {
+                        EmojiText(
+                            emojiPicks.emojiPresentationAll(),
+                            maxLines = 1,
+                            overflow = TextOverflow.Ellipsis,
+                            modifier = Modifier.semantics { contentDescription = "Alias $emojiPicks" },
+                        )
+                    }
+                }
+            },
+            isError = aliasBlocked || error?.field == ErrorField.Alias,
             trailingIcon = {
                 Row {
                     if (emojiAlias && emojiPicks.isNotEmpty()) {
@@ -241,7 +289,10 @@ private fun FormPhase(
                     IconButton(
                         onClick = {
                             emojiAlias = !emojiAlias
-                            if (emojiAlias) onEmojiMode()
+                            // Leaving emoji mode drops the picks: keeping them
+                            // hidden would submit a random code while the user
+                            // believes an alias is set.
+                            if (emojiAlias) onEmojiMode() else emojiPicks = ""
                         },
                         enabled = !submitting,
                     ) {
@@ -255,6 +306,7 @@ private fun FormPhase(
             supportingText =
                 when {
                     error?.field == ErrorField.Alias -> ({ Text(error.message) })
+                    aliasMessage != null -> ({ Text(aliasMessage) })
                     emojiAlias && emojiCatalog != null && emojiCount > 0 ->
                         ({ Text("$emojiCount/${emojiCatalog.maxGraphemes}") })
                     else -> null
@@ -410,7 +462,7 @@ private fun FormPhase(
                 )
             },
             modifier = Modifier.fillMaxWidth(),
-            enabled = !submitting && urlOk && passwordOk,
+            enabled = !submitting && urlOk && passwordOk && !aliasBlocked,
         ) {
             if (submitting) {
                 LoadingIndicator(modifier = Modifier.height(24.dp))
diff --git a/app/src/main/kotlin/me/spoo/android/ui/components/DimIcon.kt b/app/src/main/kotlin/me/spoo/android/ui/components/DimIcon.kt
index 10c52ba..4fdb05f 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/components/DimIcon.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/components/DimIcon.kt
@@ -5,7 +5,11 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.outlined.Computer
+import androidx.compose.material.icons.outlined.DeviceUnknown
 import androidx.compose.material.icons.outlined.Public
+import androidx.compose.material.icons.outlined.Smartphone
+import androidx.compose.material.icons.outlined.TabletAndroid
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
@@ -134,6 +138,26 @@ private val BRAND_DOMAINS =
         "chrome os" to "chromeos.google",
     )
 
+/** Device-type glyph: the values are a fixed vocabulary, so real icons. */
+@Composable
+fun DeviceIcon(
+    label: String,
+    modifier: Modifier = Modifier,
+    size: Dp = 20.dp,
+) {
+    Icon(
+        when (label.lowercase()) {
+            "mobile" -> Icons.Outlined.Smartphone
+            "tablet" -> Icons.Outlined.TabletAndroid
+            "desktop" -> Icons.Outlined.Computer
+            else -> Icons.Outlined.DeviceUnknown
+        },
+        contentDescription = label,
+        modifier = modifier.size(size),
+        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+    )
+}
+
 /** Neutral monogram circle for values with no natural artwork (browsers). */
 @Composable
 fun Monogram(
@@ -150,7 +174,7 @@ fun Monogram(
         contentAlignment = Alignment.Center,
     ) {
         Text(
-            label.firstOrNull()?.uppercase() ?: "?",
+            label.firstOrNull(Char::isLetterOrDigit)?.uppercase() ?: "?",
             style = MaterialTheme.typography.labelSmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
diff --git a/app/src/main/kotlin/me/spoo/android/ui/components/FluentEmoji.kt b/app/src/main/kotlin/me/spoo/android/ui/components/FluentEmoji.kt
index 69f946c..d195cbd 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/components/FluentEmoji.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/components/FluentEmoji.kt
@@ -42,6 +42,20 @@ fun FluentEmoji(
     )
 }
 
+/**
+ * Whether a codepoint has bundled Fluent artwork. Deliberately narrow: a
+ * "not ASCII" test also catches the middle dot that separates every widget
+ * label, whose asset lookup then fails on every single render.
+ */
+internal fun isEmojiCodePoint(cp: Int): Boolean =
+    cp in 0x1F000..0x1FAFF ||
+        cp in 0x2600..0x27BF ||
+        cp in 0x2B00..0x2BFF ||
+        cp in 0x2190..0x21FF
+
+/** Variation selector 16: a presentation hint, never its own glyph. */
+internal const val VARIATION_SELECTOR_16 = 0xFE0F
+
 /**
  * Text whose emoji render as Fluent 3D inline images. Aliases are
  * emoji-only or ASCII-only (API rule), so anything non-ASCII here is an
@@ -57,7 +71,7 @@ fun EmojiText(
     overflow: TextOverflow = TextOverflow.Clip,
     softWrap: Boolean = true,
 ) {
-    if (text.all { it.code < 128 }) {
+    if (text.codePoints().noneMatch(::isEmojiCodePoint)) {
         Text(
             text,
             modifier = modifier,
@@ -77,7 +91,11 @@ fun EmojiText(
                 val cp = text.codePointAt(i)
                 val count = Character.charCount(cp)
                 val piece = text.substring(i, i + count)
-                if (cp < 128) {
+                if (cp == VARIATION_SELECTOR_16) {
+                    i += count
+                    continue
+                }
+                if (!isEmojiCodePoint(cp)) {
                     append(piece)
                 } else {
                     val id = cp.toString(16)
diff --git a/app/src/main/kotlin/me/spoo/android/ui/components/StatsContent.kt b/app/src/main/kotlin/me/spoo/android/ui/components/StatsContent.kt
index f444121..fc1fbbe 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/components/StatsContent.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/components/StatsContent.kt
@@ -233,6 +233,36 @@ fun StatsContent(
                     },
             )
         }
+        item(key = "devices") {
+            Breakdown(
+                title = "Devices",
+                slices = stats.devices,
+                activeValues = params.filters[StatsDim.Device].orEmpty(),
+                labelFor = { it.replaceFirstChar(Char::uppercase) },
+                icon = { DeviceIcon(it) },
+                onToggle =
+                    if (filterable) {
+                        { onParamsChange(params.toggling(StatsDim.Device, it)) }
+                    } else {
+                        null
+                    },
+            )
+        }
+        item(key = "utm-sources") {
+            Breakdown(
+                title = "UTM sources",
+                slices = stats.utmSources,
+                activeValues = params.filters[StatsDim.UtmSource].orEmpty(),
+                labelFor = { it },
+                icon = { Monogram(it) },
+                onToggle =
+                    if (filterable) {
+                        { onParamsChange(params.toggling(StatsDim.UtmSource, it)) }
+                    } else {
+                        null
+                    },
+            )
+        }
         item(key = "countries") {
             Breakdown(
                 title = "Countries",
diff --git a/app/src/main/kotlin/me/spoo/android/ui/screens/AnalyticsScreen.kt b/app/src/main/kotlin/me/spoo/android/ui/screens/AnalyticsScreen.kt
index 81bd2cf..eeb205f 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/screens/AnalyticsScreen.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/screens/AnalyticsScreen.kt
@@ -60,6 +60,7 @@ import me.spoo.android.data.StatsParams
 import me.spoo.android.ui.components.BottomFade
 import me.spoo.android.ui.components.BrandIcon
 import me.spoo.android.ui.components.CountryFlag
+import me.spoo.android.ui.components.DeviceIcon
 import me.spoo.android.ui.components.Favicon
 import me.spoo.android.ui.components.Monogram
 import me.spoo.android.ui.components.StatsContent
@@ -287,6 +288,24 @@ private fun FilterSheet(
                     if (value.contains('.')) Favicon(value, size = 18.dp) else Monogram(value, size = 18.dp)
                 },
             )
+            FilterGroup(
+                "Device",
+                stats?.devices,
+                StatsDim.Device,
+                params,
+                onParamsChange,
+                labelFor = { it.replaceFirstChar(Char::uppercase) },
+                icon = { DeviceIcon(it, size = 18.dp) },
+            )
+            FilterGroup(
+                "UTM source",
+                stats?.utmSources,
+                StatsDim.UtmSource,
+                params,
+                onParamsChange,
+                labelFor = { it },
+                icon = { Monogram(it, size = 18.dp) },
+            )
             Spacer(Modifier.height(sheetBottomPadding()))
         }
     }
diff --git a/app/src/main/kotlin/me/spoo/android/ui/screens/LinksScreen.kt b/app/src/main/kotlin/me/spoo/android/ui/screens/LinksScreen.kt
index 704b273..a206022 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/screens/LinksScreen.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/screens/LinksScreen.kt
@@ -176,6 +176,7 @@ fun LinksScreen(
     val sort by viewModel.sort.collectAsState()
     val createState by viewModel.createState.collectAsState()
     val emojiCatalog by viewModel.emojiCatalog.collectAsState()
+    val aliasStatus by viewModel.aliasStatus.collectAsState()
     val editState by viewModel.editState.collectAsState()
     val actionMessage by viewModel.actionMessage.collectAsState()
     val selection by viewModel.selection.collectAsState()
@@ -357,8 +358,13 @@ fun LinksScreen(
                                 ToggleButton(
                                     checked = sort == LinkSort.Clicks,
                                     onCheckedChange = { viewModel.sort.value = LinkSort.Clicks },
-                                    shapes = ButtonGroupDefaults.connectedTrailingButtonShapes(),
+                                    shapes = ButtonGroupDefaults.connectedMiddleButtonShapes(),
                                 ) { Text("Top clicks") }
+                                ToggleButton(
+                                    checked = sort == LinkSort.LastClick,
+                                    onCheckedChange = { viewModel.sort.value = LinkSort.LastClick },
+                                    shapes = ButtonGroupDefaults.connectedTrailingButtonShapes(),
+                                ) { Text("Active") }
                                 Spacer(Modifier.weight(1f))
                                 // Bare at rest; a secondaryContainer tint appears only
                                 // while a filter is active (state via affordance, no
@@ -514,6 +520,8 @@ fun LinksScreen(
                 initialUrl = sharedUrl,
                 state = createState,
                 emojiCatalog = emojiCatalog,
+                aliasStatus = aliasStatus,
+                onAliasChanged = { viewModel.aliasInput.value = it },
                 onEmojiMode = viewModel::ensureEmojiCatalog,
                 onSubmit = viewModel::create,
                 onDismiss = {
diff --git a/app/src/main/kotlin/me/spoo/android/ui/screens/links/LinksViewModel.kt b/app/src/main/kotlin/me/spoo/android/ui/screens/links/LinksViewModel.kt
index 57de85e..30429a6 100644
--- a/app/src/main/kotlin/me/spoo/android/ui/screens/links/LinksViewModel.kt
+++ b/app/src/main/kotlin/me/spoo/android/ui/screens/links/LinksViewModel.kt
@@ -3,6 +3,7 @@ package me.spoo.android.ui.screens.links
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -12,9 +13,11 @@ import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.debounce
 import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import me.spoo.android.SpooApp
+import me.spoo.android.data.AliasStatus
 import me.spoo.android.data.CreateLinkRequest
 import me.spoo.android.data.EmojiCatalog
 import me.spoo.android.data.FriendlyError
@@ -55,7 +58,7 @@ sealed interface EditState {
     ) : EditState
 }
 
-@OptIn(FlowPreview::class)
+@OptIn(FlowPreview::class, ExperimentalCoroutinesApi::class)
 class LinksViewModel(
     private val repository: LinksRepository = SpooApp.graph.linksRepository,
 ) : ViewModel() {
@@ -75,6 +78,25 @@ class LinksViewModel(
         }
     }
 
+    /** The alias currently typed in the create sheet, for live checking. */
+    val aliasInput = MutableStateFlow("")
+
+    /**
+     * Why [aliasInput] can't be used, or [AliasStatus.Free]. Prevention
+     * only: anything unknown passes and the server stays the backstop.
+     */
+    val aliasStatus: StateFlow<AliasStatus> =
+        aliasInput
+            .debounce(400)
+            .distinctUntilChanged()
+            .mapLatest { alias ->
+                if (alias.isBlank()) {
+                    AliasStatus.Free
+                } else {
+                    runCatching { repository.aliasStatus(alias) }.getOrDefault(AliasStatus.Unknown)
+                }
+            }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), AliasStatus.Free)
+
     /** Pull-to-refresh. */
     val refreshing = MutableStateFlow(false)
 
@@ -146,6 +168,10 @@ class LinksViewModel(
 
     fun resetCreate() {
         _createState.value = CreateState.Idle
+        // A StateFlow conflates an identical value, so a surviving draft
+        // would never re-check its alias on reopen and could stay stuck
+        // on a stale "taken".
+        aliasInput.value = ""
     }
 
     private val _editState = MutableStateFlow<EditState>(EditState.Idle)
diff --git a/app/src/main/kotlin/me/spoo/android/widget/SpooWidget.kt b/app/src/main/kotlin/me/spoo/android/widget/SpooWidget.kt
index 055a77e..74ef573 100644
--- a/app/src/main/kotlin/me/spoo/android/widget/SpooWidget.kt
+++ b/app/src/main/kotlin/me/spoo/android/widget/SpooWidget.kt
@@ -2,6 +2,7 @@ package me.spoo.android.widget
 
 import android.content.Context
 import android.content.Intent
+import android.graphics.Bitmap
 import androidx.compose.runtime.remember
 import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.unit.dp
@@ -30,11 +31,13 @@ import androidx.glance.layout.Alignment
 import androidx.glance.layout.Box
 import androidx.glance.layout.Column
 import androidx.glance.layout.ContentScale
+import androidx.glance.layout.Row
 import androidx.glance.layout.Spacer
 import androidx.glance.layout.fillMaxSize
 import androidx.glance.layout.fillMaxWidth
 import androidx.glance.layout.height
 import androidx.glance.layout.padding
+import androidx.glance.layout.size
 import androidx.glance.material3.ColorProviders
 import androidx.glance.state.PreferencesGlanceStateDefinition
 import androidx.glance.text.FontFamily
@@ -44,6 +47,8 @@ import androidx.glance.text.TextStyle
 import kotlinx.coroutines.flow.first
 import me.spoo.android.MainActivity
 import me.spoo.android.SpooApp
+import me.spoo.android.ui.components.VARIATION_SELECTOR_16
+import me.spoo.android.ui.components.isEmojiCodePoint
 import me.spoo.android.ui.theme.spooColorScheme
 import java.text.NumberFormat
 
@@ -229,16 +234,7 @@ class SpooWidget : GlanceAppWidget() {
                             Alignment.Top
                         },
                 ) {
-                    Text(
-                        config.label,
-                        style =
-                            TextStyle(
-                                color = GlanceTheme.colors.onSurfaceVariant,
-                                fontSize = 11.sp,
-                                fontFamily = FontFamily.Monospace,
-                            ),
-                        maxLines = 1,
-                    )
+                    EmojiLabel(context, config.label)
                     Spacer(GlanceModifier.height(4.dp))
                     val label = NumberFormat.getIntegerInstance().format(data.total)
                     val compact = size.width.value < 220f || size.height.value < 100f
@@ -288,6 +284,72 @@ class SpooWidget : GlanceAppWidget() {
         }
     }
 
+    /**
+     * The mono micro-label, with emoji drawn from the bundled Fluent
+     * artwork: a Row can mix text runs with asset-backed images.
+     *
+     * Glance only ships generated layouts up to ten children, so a label
+     * that would need more falls back to one Text — the system font still
+     * draws the emoji, just not in Fluent.
+     */
+    @androidx.compose.runtime.Composable
+    private fun EmojiLabel(
+        context: Context,
+        label: String,
+    ) {
+        val style =
+            TextStyle(
+                color = GlanceTheme.colors.onSurfaceVariant,
+                fontSize = 11.sp,
+                fontFamily = FontFamily.Monospace,
+            )
+        // Segment first so the child count is known before emitting: a
+        // Row that overflows Glance's cap renders nothing at all.
+        val parts = mutableListOf<Pair<String, Bitmap?>>()
+        val run = StringBuilder()
+        var i = 0
+        while (i < label.length) {
+            val cp = label.codePointAt(i)
+            val count = Character.charCount(cp)
+            val piece = label.substring(i, i + count)
+            val art = if (isEmojiCodePoint(cp)) WidgetIconCache.emoji(context, cp) else null
+            if (art == null) {
+                if (cp != VARIATION_SELECTOR_16) run.append(piece)
+            } else {
+                if (run.isNotEmpty()) {
+                    parts += run.toString() to null
+                    run.clear()
+                }
+                parts += piece to art
+            }
+            i += count
+        }
+        if (run.isNotEmpty()) parts += run.toString() to null
+
+        if (parts.none { it.second != null } || parts.size > MAX_LABEL_CHILDREN) {
+            Text(label, style = style, maxLines = 1)
+            return
+        }
+        Row(verticalAlignment = Alignment.CenterVertically) {
+            parts.forEach { (text, art) ->
+                if (art == null) {
+                    Text(text, style = style, maxLines = 1)
+                } else {
+                    Image(
+                        provider = ImageProvider(art),
+                        contentDescription = text,
+                        modifier = GlanceModifier.size(13.dp),
+                    )
+                }
+            }
+        }
+    }
+
+    private companion object {
+        // Glance ships generated layouts for at most this many children.
+        const val MAX_LABEL_CHILDREN = 10
+    }
+
     @androidx.compose.runtime.Composable
     private fun SignedOutContent(context: Context) {
         Column(
diff --git a/app/src/main/kotlin/me/spoo/android/widget/WidgetConfig.kt b/app/src/main/kotlin/me/spoo/android/widget/WidgetConfig.kt
index d7d55c3..888f09f 100644
--- a/app/src/main/kotlin/me/spoo/android/widget/WidgetConfig.kt
+++ b/app/src/main/kotlin/me/spoo/android/widget/WidgetConfig.kt
@@ -73,7 +73,7 @@ data class WidgetConfig(
         get() =
             listOfNotNull(
                 scope?.let { "/$it" },
-                if (chart.timeChart) null else effectiveDimension.name.uppercase(),
+                if (chart.timeChart) null else effectiveDimension.display.uppercase(),
                 metricLabel,
                 rangeLabel,
                 if (filters.isNotEmpty()) "FILTERED" else null,
@@ -109,7 +109,9 @@ data class WidgetData(
     val series: List<Int>,
     val slices: List<LinkStats.Slice>,
 ) {
-    fun encodeSlices() = slices.joinToString("\n") { "${it.label}\t${it.count}" }
+    // Tab-separated, newline-delimited: a label carrying either would
+    // corrupt the record, so escape on the way in.
+    fun encodeSlices() = slices.joinToString("\n") { "${it.label.escapeSeparators()}\t${it.count}" }
 
     companion object {
         fun decodeSlices(raw: String?): List<LinkStats.Slice> =
@@ -117,8 +119,42 @@ data class WidgetData(
                 val tab = line.lastIndexOf('\t')
                 if (tab <= 0) return@mapNotNull null
                 val count = line.substring(tab + 1).toIntOrNull() ?: return@mapNotNull null
-                LinkStats.Slice(line.substring(0, tab), count)
+                LinkStats.Slice(line.substring(0, tab).unescapeSeparators(), count)
             }
+
+        private fun String.escapeSeparators() = replace("\\", "\\\\").replace("\n", "\\n").replace("\t", "\\t")
+
+        private fun String.unescapeSeparators(): String {
+            val out = StringBuilder(length)
+            var i = 0
+            while (i < length) {
+                val c = this[i]
+                if (c == '\\' && i + 1 < length) {
+                    when (this[i + 1]) {
+                        'n' -> {
+                            out.append('\n')
+                            i += 2
+                        }
+                        't' -> {
+                            out.append('\t')
+                            i += 2
+                        }
+                        '\\' -> {
+                            out.append('\\')
+                            i += 2
+                        }
+                        else -> {
+                            out.append(c)
+                            i++
+                        }
+                    }
+                } else {
+                    out.append(c)
+                    i++
+                }
+            }
+            return out.toString()
+        }
     }
 }
 
@@ -132,6 +168,8 @@ fun LinkStats.toWidgetData(config: WidgetConfig) =
                 StatsDim.Browser -> browsers
                 StatsDim.Os -> os
                 StatsDim.Referrer -> referrers
+                StatsDim.Device -> devices
+                StatsDim.UtmSource -> utmSources
             },
     )
 
diff --git a/app/src/main/kotlin/me/spoo/android/widget/WidgetConfigActivity.kt b/app/src/main/kotlin/me/spoo/android/widget/WidgetConfigActivity.kt
index 6e116b3..e9a759a 100644
--- a/app/src/main/kotlin/me/spoo/android/widget/WidgetConfigActivity.kt
+++ b/app/src/main/kotlin/me/spoo/android/widget/WidgetConfigActivity.kt
@@ -41,6 +41,7 @@ import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
 import androidx.compose.material3.FilterChip
 import androidx.compose.material3.Icon
 import androidx.compose.material3.LoadingIndicator
+import androidx.compose.material3.LocalTextStyle
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.MediumFlexibleTopAppBar
 import androidx.compose.material3.RadioButton
@@ -83,6 +84,8 @@ import me.spoo.android.data.StatsDim
 import me.spoo.android.data.StatsMetric
 import me.spoo.android.ui.components.BrandIcon
 import me.spoo.android.ui.components.CountryFlag
+import me.spoo.android.ui.components.DeviceIcon
+import me.spoo.android.ui.components.EmojiText
 import me.spoo.android.ui.components.Favicon
 import me.spoo.android.ui.components.Monogram
 import me.spoo.android.ui.components.countryDisplayName
@@ -321,7 +324,19 @@ private fun ConfigScreen(
                                 Triple<StatsDim, String, ImageVector?>(StatsDim.Browser, "Browser", null),
                                 Triple<StatsDim, String, ImageVector?>(StatsDim.Os, "OS", null),
                                 Triple<StatsDim, String, ImageVector?>(StatsDim.Referrer, "Referrer", null),
+                            ),
+                        selected = config.dimension,
+                        onSelect = { config = config.copy(dimension = it) },
+                    )
+                }
+                item { Spacer(Modifier.height(6.dp)) }
+                item {
+                    ToggleRow(
+                        options =
+                            listOf(
                                 Triple<StatsDim, String, ImageVector?>(StatsDim.Country, "Country", null),
+                                Triple<StatsDim, String, ImageVector?>(StatsDim.Device, "Device", null),
+                                Triple<StatsDim, String, ImageVector?>(StatsDim.UtmSource, "UTM source", null),
                             ),
                         selected = config.dimension,
                         onSelect = { config = config.copy(dimension = it) },
@@ -371,7 +386,7 @@ private fun ConfigScreen(
                 ) {
                     Favicon(host = faviconHost(link.originalUrl), size = 20.dp)
                     Spacer(Modifier.width(12.dp))
-                    Text(
+                    EmojiText(
                         "/${link.shortCode}",
                         style = MaterialTheme.typography.bodyLarge,
                         modifier = Modifier.weight(1f),
@@ -430,6 +445,28 @@ private fun ConfigScreen(
                     },
                 )
             }
+            item {
+                FilterGroup(
+                    "Device",
+                    stats?.devices,
+                    StatsDim.Device,
+                    config,
+                    onConfigChange = { config = it },
+                    labelFor = { it.replaceFirstChar(Char::uppercase) },
+                    icon = { DeviceIcon(it, size = 18.dp) },
+                )
+            }
+            item {
+                FilterGroup(
+                    "UTM source",
+                    stats?.utmSources,
+                    StatsDim.UtmSource,
+                    config,
+                    onConfigChange = { config = it },
+                    labelFor = { it },
+                    icon = { Monogram(it, size = 18.dp) },
+                )
+            }
             item { Spacer(Modifier.height(16.dp)) }
         }
     }
@@ -529,10 +566,9 @@ private fun WidgetPreview(
                         Arrangement.Top
                     },
             ) {
-                Text(
+                EmojiText(
                     config.label,
-                    fontSize = 11.sp,
-                    fontFamily = FontFamily.Monospace,
+                    style = LocalTextStyle.current.copy(fontSize = 11.sp, fontFamily = FontFamily.Monospace),
                     color = widgetScheme.onSurfaceVariant,
                     maxLines = 1,
                 )
diff --git a/app/src/main/kotlin/me/spoo/android/widget/WidgetIconCache.kt b/app/src/main/kotlin/me/spoo/android/widget/WidgetIconCache.kt
index 092b7b6..087eaef 100644
--- a/app/src/main/kotlin/me/spoo/android/widget/WidgetIconCache.kt
+++ b/app/src/main/kotlin/me/spoo/android/widget/WidgetIconCache.kt
@@ -21,6 +21,10 @@ import java.util.concurrent.ConcurrentHashMap
 object WidgetIconCache {
     private val memory = ConcurrentHashMap<String, Bitmap>()
 
+    // Fluent has no model for a handful of multi-codepoint emoji; remember
+    // the misses so a widget doesn't retry the asset on every render.
+    private val missingEmoji = ConcurrentHashMap.newKeySet<Int>()
+
     /** The favicon host behind a dimension value, null when none applies. */
     fun hostFor(
         dim: StatsDim,
@@ -30,6 +34,7 @@ object WidgetIconCache {
             StatsDim.Browser, StatsDim.Os -> brandDomain(label)
             StatsDim.Referrer -> label.takeIf { it.contains('.') }
             StatsDim.Country -> null // flags are emoji, no fetch needed
+            StatsDim.Device, StatsDim.UtmSource -> null // no favicon identity
         }
 
     fun get(
@@ -72,4 +77,24 @@ object WidgetIconCache {
         context: Context,
         host: String,
     ) = File(context.cacheDir, "widget-icons/${host.replace('/', '_')}.png")
+
+    /**
+     * Bundled Fluent artwork for one emoji codepoint, null when Fluent has
+     * no single-codepoint model for it. Assets are tiny webps; decoding
+     * once per process is fine for label-sized use.
+     */
+    fun emoji(
+        context: Context,
+        codePoint: Int,
+    ): Bitmap? {
+        val key = "emoji/${codePoint.toString(16)}"
+        memory[key]?.let { return it }
+        if (codePoint in missingEmoji) return null
+        val bitmap =
+            runCatching {
+                context.assets.open("$key.webp").use(BitmapFactory::decodeStream)
+            }.getOrNull()
+        if (bitmap == null) missingEmoji += codePoint else memory[key] = bitmap
+        return bitmap
+    }
 }
diff --git a/app/src/test/kotlin/me/spoo/android/data/ErrorsTest.kt b/app/src/test/kotlin/me/spoo/android/data/ErrorsTest.kt
new file mode 100644
index 0000000..d2f3640
--- /dev/null
+++ b/app/src/test/kotlin/me/spoo/android/data/ErrorsTest.kt
@@ -0,0 +1,32 @@
+package me.spoo.android.data
+
+import me.spoo.SpooDecodeException
+import me.spoo.SpooIOException
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+
+// SDK exceptions with internal constructors (validation, rate limit, ...)
+// are exercised end to end against the live backend instead; these cover
+// the publicly constructible paths and the fallback contract.
+class ErrorsTest {
+    @Test
+    fun `io failures become a connectivity sentence`() {
+        val friendly = friendlyError(SpooIOException("timeout", null), "fallback")
+        assertEquals("Can't reach spoo.me. Check your connection and try again.", friendly.message)
+        assertNull(friendly.field)
+    }
+
+    @Test
+    fun `decode failures suggest updating the app`() {
+        val friendly = friendlyError(SpooDecodeException("bad json", null), "fallback")
+        assertEquals("Unexpected response from the server. Try updating the app.", friendly.message)
+    }
+
+    @Test
+    fun `unknown failures fall back verbatim`() {
+        val friendly = friendlyError(IllegalStateException("boom"), "Couldn't create the link.")
+        assertEquals("Couldn't create the link.", friendly.message)
+        assertNull(friendly.field)
+    }
+}
diff --git a/app/src/test/kotlin/me/spoo/android/data/MockLinksRepositoryTest.kt b/app/src/test/kotlin/me/spoo/android/data/MockLinksRepositoryTest.kt
new file mode 100644
index 0000000..8e0cae3
--- /dev/null
+++ b/app/src/test/kotlin/me/spoo/android/data/MockLinksRepositoryTest.kt
@@ -0,0 +1,127 @@
+package me.spoo.android.data
+
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+
+// The mock is the offline stand-in for the server list endpoint, so its
+// query engine has to honor the same contract: filter, search, sort,
+// then page.
+class MockLinksRepositoryTest {
+    @Test
+    fun `refresh resets to the first page and more exists`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery())
+            assertEquals(25, repo.links.value.size)
+            assertTrue(repo.hasMore.value)
+        }
+
+    @Test
+    fun `loadMore appends a page without duplicates`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery())
+            repo.loadMore()
+            val links = repo.links.value
+            assertEquals(50, links.size)
+            assertEquals(links.size, links.map { it.id }.distinct().size)
+        }
+
+    @Test
+    fun `click sort is descending by total clicks`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery(sort = LinkSort.Clicks))
+            val clicks = repo.links.value.map { it.totalClicks }
+            assertEquals(clicks.sortedDescending(), clicks)
+        }
+
+    @Test
+    fun `search narrows across the whole set, not the visible page`() =
+        runTest {
+            val repo = MockLinksRepository()
+            // Matches sit past the first page, so a search that filtered
+            // only the loaded page would return fewer of them.
+            repo.refresh(LinksQuery())
+            val firstPage = repo.links.value
+            val onPage = firstPage.count { it.originalUrl.contains("dev.to") }
+            repo.refresh(LinksQuery(search = "dev.to"))
+            val found = repo.links.value
+            assertTrue(found.size > onPage, "search saw only the loaded page")
+            assertTrue(found.all { it.originalUrl.contains("dev.to", ignoreCase = true) })
+        }
+
+    @Test
+    fun `password filter keeps only protected links`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery(filter = LinksFilter(passwordProtected = true)))
+            assertTrue(repo.links.value.isNotEmpty())
+            assertTrue(repo.links.value.all { it.hasPassword })
+        }
+
+    @Test
+    fun `last-click sort is descending, and every stamp is plausible`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery(sort = LinkSort.LastClick))
+            val links = repo.links.value
+            val stamps = links.mapNotNull { it.lastClickMillis }
+            assertEquals(stamps.sortedDescending(), stamps)
+            // A last click before the link existed, or in the future, is
+            // the kind of nonsense that only shows up in a demo.
+            val now = System.currentTimeMillis()
+            links.forEach { link ->
+                val clicked = link.lastClickMillis ?: return@forEach
+                assertTrue(clicked <= now, "${'$'}{link.shortCode} clicked in the future")
+                link.createdAtMillis?.let {
+                    assertTrue(clicked >= it, "${'$'}{link.shortCode} clicked before it existed")
+                }
+            }
+        }
+
+    @Test
+    fun `never-clicked links sort after clicked ones`() =
+        runTest {
+            val repo = MockLinksRepository()
+            val fresh = repo.create(CreateLinkRequest(url = "https://example.com", alias = "brand-new"))
+            assertEquals(null, fresh.lastClickMillis)
+            repo.refresh(LinksQuery(sort = LinkSort.LastClick))
+            // On whatever page is visible, a clicked link never follows an
+            // unclicked one.
+            val seen = repo.links.value.map { it.lastClickMillis }
+            val firstNull = seen.indexOfFirst { it == null }
+            if (firstNull >= 0) assertTrue(seen.drop(firstNull).all { it == null })
+        }
+
+    @Test
+    fun `alias status separates taken from reserved and invalid`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery())
+            val taken =
+                repo.links.value
+                    .first()
+                    .shortCode
+            // A blocked alias is not automatically a taken one: the copy
+            // under the field depends on telling these apart.
+            assertEquals(AliasStatus.Taken, repo.aliasStatus(taken))
+            assertEquals(AliasStatus.Reserved, repo.aliasStatus("api"))
+            assertEquals(AliasStatus.Invalid, repo.aliasStatus("hi"))
+            assertEquals(AliasStatus.Free, repo.aliasStatus("definitely-free-alias"))
+        }
+
+    @Test
+    fun `refresh after a filtered query with null reruns the same query`() =
+        runTest {
+            val repo = MockLinksRepository()
+            repo.refresh(LinksQuery(filter = LinksFilter(passwordProtected = true)))
+            val filtered = repo.links.value.size
+            repo.refresh(null)
+            assertEquals(filtered, repo.links.value.size)
+            assertTrue(repo.links.value.all { it.hasPassword })
+        }
+}
diff --git a/app/src/test/kotlin/me/spoo/android/ui/components/EmojiTest.kt b/app/src/test/kotlin/me/spoo/android/ui/components/EmojiTest.kt
new file mode 100644
index 0000000..9f4a81d
--- /dev/null
+++ b/app/src/test/kotlin/me/spoo/android/ui/components/EmojiTest.kt
@@ -0,0 +1,32 @@
+package me.spoo.android.ui.components
+
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+// Widget labels join with a middle dot, so "is this ASCII?" is the wrong
+// question to ask about a codepoint: it sends every separator down the
+// artwork path, where the asset lookup fails on every render.
+class EmojiTest {
+    @Test
+    fun `label separators are not treated as emoji`() {
+        assertFalse(isEmojiCodePoint('·'.code))
+        assertFalse(isEmojiCodePoint('/'.code))
+        assertFalse(isEmojiCodePoint('A'.code))
+        assertFalse(isEmojiCodePoint('9'.code))
+    }
+
+    @Test
+    fun `real emoji are detected`() {
+        assertTrue(isEmojiCodePoint("🎮".codePointAt(0)))
+        assertTrue(isEmojiCodePoint("🔥".codePointAt(0)))
+        assertTrue(isEmojiCodePoint("😎".codePointAt(0)))
+        assertTrue(isEmojiCodePoint("✨".codePointAt(0)))
+    }
+
+    @Test
+    fun `a plain widget label needs no artwork at all`() {
+        val label = "CLICKS · 30D"
+        assertTrue(label.codePoints().noneMatch(::isEmojiCodePoint))
+    }
+}
diff --git a/app/src/test/kotlin/me/spoo/android/ui/components/ValidationTest.kt b/app/src/test/kotlin/me/spoo/android/ui/components/ValidationTest.kt
new file mode 100644
index 0000000..60093c8
--- /dev/null
+++ b/app/src/test/kotlin/me/spoo/android/ui/components/ValidationTest.kt
@@ -0,0 +1,69 @@
+package me.spoo.android.ui.components
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class ValidationTest {
+    @Test
+    fun `normalizeUrl prepends https when no scheme was typed`() {
+        assertEquals("https://example.com/promo", normalizeUrl("example.com/promo"))
+        assertEquals("https://spoo.me", normalizeUrl("  spoo.me  "))
+    }
+
+    @Test
+    fun `normalizeUrl leaves explicit schemes alone, typos included`() {
+        assertEquals("http://example.com", normalizeUrl("http://example.com"))
+        assertEquals("htp://example.com", normalizeUrl("htp://example.com"))
+        assertEquals("spoo://oauth/callback", normalizeUrl("spoo://oauth/callback"))
+    }
+
+    @Test
+    fun `normalizeUrl keeps empty input empty`() {
+        assertEquals("", normalizeUrl("   "))
+    }
+
+    @Test
+    fun `isLikelyUrl accepts hosts with a dot and localhost`() {
+        assertTrue(isLikelyUrl("example.com"))
+        assertTrue(isLikelyUrl("https://sub.domain.dev/path?q=1"))
+        assertTrue(isLikelyUrl("http://localhost:8000/x"))
+    }
+
+    @Test
+    fun `isLikelyUrl rejects non-urls`() {
+        assertFalse(isLikelyUrl(""))
+        assertFalse(isLikelyUrl("not a url"))
+        assertFalse(isLikelyUrl("hello"))
+        assertFalse(isLikelyUrl("htp://typo.example.com"))
+        assertFalse(isLikelyUrl("ftp://example.com"))
+    }
+
+    @Test
+    fun `password policy needs length, letter, digit, and @ or dot`() {
+        assertTrue(isAcceptablePassword("word.word.42"))
+        assertTrue(isAcceptablePassword("Str0ng@pass"))
+        assertFalse(isAcceptablePassword("short.1"))
+        assertFalse(isAcceptablePassword("no-digits.here"))
+        assertFalse(isAcceptablePassword("0123456789"))
+        assertFalse(isAcceptablePassword("letters4nddigits"))
+    }
+
+    @Test
+    fun `alias characters are alphanumerics, underscore, hyphen`() {
+        assertTrue("Fable-42_x".all(::isAliasChar))
+        assertFalse(isAliasChar(' '))
+        assertFalse(isAliasChar('/'))
+        assertFalse(isAliasChar('é'))
+    }
+
+    @Test
+    fun `suggested passwords always satisfy the policy`() {
+        repeat(200) {
+            val suggestion = suggestPassword()
+            assertTrue(isAcceptablePassword(suggestion), "rejected: $suggestion")
+            assertTrue(Regex("^[a-z]+\\.[a-z]+\\.[a-z]+\\.\\d{3}$").matches(suggestion), "shape: $suggestion")
+        }
+    }
+}
diff --git a/app/src/test/kotlin/me/spoo/android/widget/WidgetConfigTest.kt b/app/src/test/kotlin/me/spoo/android/widget/WidgetConfigTest.kt
new file mode 100644
index 0000000..5a70edc
--- /dev/null
+++ b/app/src/test/kotlin/me/spoo/android/widget/WidgetConfigTest.kt
@@ -0,0 +1,118 @@
+package me.spoo.android.widget
+
+import androidx.datastore.preferences.core.mutablePreferencesOf
+import me.spoo.android.data.StatsDim
+import me.spoo.android.data.StatsMetric
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class WidgetConfigTest {
+    @Test
+    fun `config round-trips through glance state`() {
+        val config =
+            WidgetConfig(
+                chart = WidgetChart.Treemap,
+                font = WidgetFont.Serif,
+                dimension = StatsDim.Referrer,
+                metric = StatsMetric.UniqueClicks,
+                scope = "mixtape",
+                filters = mapOf(StatsDim.Country to "DE", StatsDim.Browser to "Firefox"),
+                rangeDays = 90,
+            )
+        val prefs = mutablePreferencesOf()
+        prefs.writeWidgetConfig(config)
+        assertEquals(config, prefs.readWidgetConfig())
+    }
+
+    @Test
+    fun `all-time range survives the zero encoding`() {
+        val prefs = mutablePreferencesOf()
+        prefs.writeWidgetConfig(WidgetConfig(rangeDays = null))
+        assertEquals(null, prefs.readWidgetConfig().rangeDays)
+    }
+
+    @Test
+    fun `empty state falls back to defaults, not crashes`() {
+        assertEquals(WidgetConfig(), mutablePreferencesOf().readWidgetConfig())
+    }
+
+    @Test
+    fun `unknown enum names fall back instead of crashing`() {
+        val prefs = mutablePreferencesOf()
+        prefs.writeWidgetConfig(WidgetConfig())
+        prefs[WidgetKeys.STYLE] = "Outline"
+        prefs[WidgetKeys.FONT] = "ComicSans"
+        val read = prefs.readWidgetConfig()
+        assertEquals(WidgetChart.Wave, read.chart)
+        assertEquals(WidgetFont.Flex, read.font)
+    }
+
+    @Test
+    fun `saving a config drops the previous scope's cached data`() {
+        val prefs = mutablePreferencesOf()
+        prefs.writeWidgetData(WidgetData(total = 5, series = listOf(1, 2), slices = emptyList()))
+        prefs.writeWidgetConfig(WidgetConfig(scope = "other"))
+        assertEquals(0L, prefs.readWidgetData().total)
+        assertEquals(emptyList(), prefs.readWidgetData().series)
+    }
+
+    @Test
+    fun `label uses display names, so UTM source does not read UTMSOURCE`() {
+        val config = WidgetConfig(chart = WidgetChart.Treemap, dimension = StatsDim.UtmSource)
+        assertEquals("UTM SOURCE · CLICKS · 30D", config.label)
+        assertEquals(
+            "DEVICE · CLICKS · 30D",
+            WidgetConfig(chart = WidgetChart.Bubbles, dimension = StatsDim.Device).label,
+        )
+    }
+
+    @Test
+    fun `slices with tabs and newlines in labels round-trip`() {
+        val data =
+            WidgetData(
+                total = 3,
+                series = listOf(1, 1, 1),
+                slices =
+                    listOf(
+                        // The encoding is tab-separated, newline-delimited:
+                        // both separators have to survive inside a label.
+                        me.spoo.android.data.LinkStats
+                            .Slice("Samsung\tInternet", 2),
+                        me.spoo.android.data.LinkStats
+                            .Slice("multi\nline", 1),
+                    ),
+            )
+        val prefs = mutablePreferencesOf()
+        prefs.writeWidgetData(data)
+        assertEquals(data.slices, prefs.readWidgetData().slices)
+    }
+
+    @Test
+    fun `label carries scope, dimension, metric, range, and filter flag`() {
+        val config =
+            WidgetConfig(
+                chart = WidgetChart.Bubbles,
+                dimension = StatsDim.Browser,
+                metric = StatsMetric.Clicks,
+                scope = "mixtape",
+                filters = mapOf(StatsDim.Country to "DE"),
+                rangeDays = 7,
+            )
+        assertEquals("/mixtape · BROWSER · CLICKS · 7D · FILTERED", config.label)
+        assertEquals("CLICKS · 30D", WidgetConfig().label)
+    }
+
+    @Test
+    fun `picker shells prefill their chart`() {
+        assertEquals(WidgetChart.Bars, WidgetConfig.presetFor("x.BarsWidgetReceiver").chart)
+        assertEquals(WidgetChart.Number, WidgetConfig.presetFor("x.CountWidgetReceiver").chart)
+        assertEquals(null, WidgetConfig.presetFor("x.CountWidgetReceiver").rangeDays)
+        assertEquals(WidgetChart.Wave, WidgetConfig.presetFor(null).chart)
+    }
+
+    @Test
+    fun `map chart always breaks down by country`() {
+        val config = WidgetConfig(chart = WidgetChart.Map, dimension = StatsDim.Browser)
+        assertEquals(StatsDim.Country, config.effectiveDimension)
+    }
+}
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 268a066..2c7e4e2 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -10,6 +10,7 @@ coreKtx = "1.16.0"
 lifecycle = "2.9.2"
 kotlinxSerialization = "1.11.0"
 spooSdk = "0.1.0"
+coroutines = "1.10.2"
 
 [libraries]
 androidx-core-ktx = { module = "androidx.core:core-ktx", version.ref = "coreKtx" }
@@ -28,6 +29,10 @@ glance-appwidget = { module = "androidx.glance:glance-appwidget", version = "1.2
 glance-material3 = { module = "androidx.glance:glance-material3", version = "1.2.0-rc01" }
 work-runtime = { module = "androidx.work:work-runtime-ktx", version = "2.10.3" }
 compose-bom = { module = "androidx.compose:compose-bom", version.ref = "composeBom" }
+junit = { module = "junit:junit", version = "4.13.2" }
+kotlin-test = { module = "org.jetbrains.kotlin:kotlin-test-junit", version.ref = "kotlin" }
+kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "coroutines" }
+turbine = { module = "app.cash.turbine:turbine", version = "1.2.1" }
 compose-ui = { module = "androidx.compose.ui:ui" }
 compose-ui-tooling = { module = "androidx.compose.ui:ui-tooling" }
 compose-ui-tooling-preview = { module = "androidx.compose.ui:ui-tooling-preview" }