Add feature-usage tracking and dashboard charts

Instruments FeatureEvaluationService with System.Diagnostics.Metrics (Counter + IMeterFactory). Accumulates per-feature/day evaluation counts in-process, flushed every 30s to a new FeatureUsageDaily Postgres table via PostgreSQL ON CONFLICT upsert. Caches dashboard query results for 180s in IMemoryCache. New GET /api/v1/environments/{id}/usage endpoint returns top-10 features last day and 14-day per-day breakdown. Admin dashboard shows two ApexCharts bar charts: top features and evaluations by day with per-flag hover tooltip.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/admin/package-lock.json

@@ -12,10 +12,12 @@
         "@iconify-json/ri": "^1.2.0",
         "@iconify/vue": "^4.1.0",
         "@vueuse/core": "^11.0.0",
+        "apexcharts": "^5.15.0",
         "axios": "^1.15.0",
         "pinia": "^3.0.4",
         "vue": "^3.4.0",
         "vue-router": "^4.3.0",
+        "vue3-apexcharts": "^1.11.1",
         "vue3-perfect-scrollbar": "^2.0.0",
         "vuetify": "^3.7.5"
       },
@@ -4281,6 +4283,11 @@
         "node": ">= 8"
       }
     },
+    "node_modules/apexcharts": {
+      "version": "5.15.0",
+      "resolved": "https://registry.npmjs.org/apexcharts/-/apexcharts-5.15.0.tgz",
+      "integrity": "sha512-ATswoiZi8wynKcwqf0eyE0Is5mBQoDpxZN3PlSVy41OrD+9GMBp2kZQRjyGK+5/j0GFjHkuAd7GKOrt5VMoPrw=="
+    },
     "node_modules/argparse": {
       "version": "1.0.10",
       "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
@@ -11130,6 +11137,20 @@
       "integrity": "sha512-sGhTPMuXqZ1rVOk32RylztWkfXTRhuS7vgAKv0zjqk8gbsHkJ7xfFf+jbySxt7tWObEJwyKaHMikV/WGDiQm8g==",
       "license": "MIT"
     },
+    "node_modules/vue3-apexcharts": {
+      "version": "1.11.1",
+      "resolved": "https://registry.npmjs.org/vue3-apexcharts/-/vue3-apexcharts-1.11.1.tgz",
+      "integrity": "sha512-MbN3vg8bMG19wc0Lm1HkeQvODgLm56DgpIxtNUO0xpf/JCzYWVGE4jzXp2JISzy2s3Kul1yOxNQUYsLvKQ5L9g==",
+      "peerDependencies": {
+        "apexcharts": ">=5.10.0",
+        "vue": ">=3.0.0"
+      },
+      "peerDependenciesMeta": {
+        "apexcharts": {
+          "optional": false
+        }
+      }
+    },
     "node_modules/vue3-perfect-scrollbar": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/vue3-perfect-scrollbar/-/vue3-perfect-scrollbar-2.0.0.tgz",

src/admin/package.json

@@ -14,10 +14,12 @@
     "@iconify-json/ri": "^1.2.0",
     "@iconify/vue": "^4.1.0",
     "@vueuse/core": "^11.0.0",
+    "apexcharts": "^5.15.0",
     "axios": "^1.15.0",
     "pinia": "^3.0.4",
     "vue": "^3.4.0",
     "vue-router": "^4.3.0",
+    "vue3-apexcharts": "^1.11.1",
     "vue3-perfect-scrollbar": "^2.0.0",
     "vuetify": "^3.7.5"
   },

src/admin/src/api/usage.ts

@@ -0,0 +1,7 @@
+import apiClient from './client';
+import type { DashboardUsageResponse } from '@/types/api';
+
+export async function getUsageDashboard(environmentId: number, days = 14): Promise<DashboardUsageResponse> {
+  const { data } = await apiClient.get<DashboardUsageResponse>(`/v1/environments/${environmentId}/usage`, { params: { days } });
+  return data;
+}

src/admin/src/components/dashboard/DailyUsageChart.vue

@@ -0,0 +1,119 @@
+<template>
+  <apexchart type="bar" :options="chartOptions" :series="series" height="280" />
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue';
+import type { DailyUsage } from '@/types/api';
+
+const props = defineProps<{
+  data: DailyUsage[];
+}>();
+
+const series = computed(() => [
+  {
+    name: 'Evaluations',
+    data: props.data.map((d) => d.totalCount),
+  },
+]);
+
+function formatDate(iso: string): string {
+  const parts = iso.split('-');
+  return parts.length === 3 ? `${parts[1]}/${parts[2]}` : iso;
+}
+
+const chartOptions = computed(() => {
+  const dailyData = props.data;
+  return {
+    chart: {
+      type: 'bar',
+      toolbar: { show: false },
+      animations: { enabled: false },
+    },
+    plotOptions: {
+      bar: {
+        columnWidth: '55%',
+        borderRadius: 4,
+      },
+    },
+    dataLabels: { enabled: false },
+    xaxis: {
+      categories: dailyData.map((d) => d.date),
+      labels: {
+        style: { colors: '#8A8D93', fontSize: '12px' },
+        formatter: (val: string) => formatDate(val),
+      },
+      axisBorder: { show: false },
+      axisTicks: { show: false },
+    },
+    yaxis: {
+      labels: { style: { colors: '#8A8D93', fontSize: '12px' } },
+    },
+    colors: ['#8C57FF'],
+    grid: { borderColor: '#E0E0E0', strokeDashArray: 4 },
+    tooltip: {
+      custom: ({ dataPointIndex }: { dataPointIndex: number }) => {
+        const day = dailyData[dataPointIndex];
+        if (!day) return '';
+        const flagRows = day.features
+          .slice(0, 10)
+          .map(
+            (f) =>
+              `<div class="apex-day-tooltip__row"><span>${f.featureName}</span><strong>${f.count.toLocaleString()}</strong></div>`,
+          )
+          .join('');
+        const moreCount = day.features.length - 10;
+        const moreRow = moreCount > 0 ? `<div class="apex-day-tooltip__more">+${moreCount} more</div>` : '';
+        return `
+          <div class="apex-day-tooltip">
+            <div class="apex-day-tooltip__header">${day.date} &mdash; ${day.totalCount.toLocaleString()} total</div>
+            ${flagRows}${moreRow}
+          </div>`;
+      },
+    },
+  };
+});
+</script>
+
+<style>
+.apex-day-tooltip {
+  padding: 10px 14px;
+  font-family: inherit;
+  min-width: 200px;
+  max-width: 300px;
+  background: #fff;
+  border: 1px solid #e0e0e0;
+  border-radius: 6px;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
+}
+
+.apex-day-tooltip__header {
+  font-weight: 600;
+  margin-bottom: 8px;
+  font-size: 0.82rem;
+  color: #2e263d;
+  border-bottom: 1px solid #f0f0f0;
+  padding-bottom: 6px;
+}
+
+.apex-day-tooltip__row {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 16px;
+  font-size: 0.8rem;
+  padding: 2px 0;
+  color: #555;
+}
+
+.apex-day-tooltip__row strong {
+  color: #8c57ff;
+  font-weight: 600;
+}
+
+.apex-day-tooltip__more {
+  font-size: 0.75rem;
+  color: #9e9e9e;
+  margin-top: 4px;
+}
+</style>

src/admin/src/components/dashboard/TopFeaturesChart.vue

@@ -0,0 +1,49 @@
+<template>
+  <apexchart type="bar" :options="chartOptions" :series="series" height="280" />
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue';
+import type { TopFeatureUsage } from '@/types/api';
+
+const props = defineProps<{
+  data: TopFeatureUsage[];
+}>();
+
+const series = computed(() => [
+  {
+    name: 'Evaluations',
+    data: props.data.map((f) => f.count),
+  },
+]);
+
+const chartOptions = computed(() => ({
+  chart: {
+    type: 'bar',
+    toolbar: { show: false },
+    animations: { enabled: false },
+  },
+  plotOptions: {
+    bar: {
+      horizontal: true,
+      borderRadius: 4,
+      dataLabels: { position: 'top' },
+    },
+  },
+  dataLabels: { enabled: false },
+  xaxis: {
+    categories: props.data.map((f) => f.featureName),
+    labels: { style: { colors: '#8A8D93', fontSize: '12px' } },
+    axisBorder: { show: false },
+    axisTicks: { show: false },
+  },
+  yaxis: {
+    labels: { style: { colors: '#8A8D93', fontSize: '12px' } },
+  },
+  colors: ['#8C57FF'],
+  grid: { borderColor: '#E0E0E0', strokeDashArray: 4, yaxis: { lines: { show: false } } },
+  tooltip: {
+    y: { formatter: (val: number) => `${val.toLocaleString()} evaluations` },
+  },
+}));
+</script>

src/admin/src/components/identities/IdentityDetail.vue

@@ -320,6 +320,7 @@ const props = defineProps<Props>();
 const emit = defineEmits<{
   'update:modelValue': [value: boolean];
   deleted: [identityId: number];
+  updated: [identity: IdentityResponse];
 }>();
 
 const contextStore = useContextStore();
@@ -420,6 +421,10 @@ watch(
   { immediate: true },
 );
 
+watch(activeTab, (tab) => {
+  if (tab === 'segments') loadSegmentsData();
+});
+
 async function onToggleOverride(override: FeatureStateResponse, enabled: boolean | null): Promise<void> {
   if (enabled === null || !props.identity) return;
   const envApiKey = contextStore.currentEnvironment?.apiKey;
@@ -489,6 +494,12 @@ async function onAddOverride(): Promise<void> {
   }
 }
 
+function emitTraitsUpdated(): void {
+  if (props.identity) {
+    emit('updated', { ...props.identity, traits: [...editedTraits.value] });
+  }
+}
+
 async function onSaveTrait(key: string, value: string): Promise<void> {
   if (!props.identity) return;
   const envApiKey = contextStore.currentEnvironment?.apiKey;
@@ -499,6 +510,7 @@ async function onSaveTrait(key: string, value: string): Promise<void> {
     await upsertIdentityTrait(envApiKey, props.identity.id, key, { value });
     const idx = editedTraits.value.findIndex((t: TraitResponse) => t.key === key);
     if (idx >= 0) editedTraits.value[idx] = { key, value };
+    emitTraitsUpdated();
   } catch {
     traitsError.value = 'Failed to save trait. Please try again.';
   } finally {
@@ -515,6 +527,7 @@ async function onDeleteTrait(key: string): Promise<void> {
   try {
     await deleteIdentityTrait(envApiKey, props.identity.id, key);
     editedTraits.value = editedTraits.value.filter((t: TraitResponse) => t.key !== key);
+    emitTraitsUpdated();
   } catch {
     traitsError.value = 'Failed to delete trait. Please try again.';
   } finally {
@@ -540,6 +553,7 @@ async function onAddTrait(): Promise<void> {
     }
     newTraitKey.value = '';
     newTraitValue.value = '';
+    emitTraitsUpdated();
   } catch {
     traitsError.value = 'Failed to add trait. Please try again.';
   } finally {

src/admin/src/main.ts

@@ -1,5 +1,6 @@
 import { createApp } from 'vue';
 import { createPinia } from 'pinia';
+import VueApexCharts from 'vue3-apexcharts';
 import App from './App.vue';
 
 // Styles
@@ -15,6 +16,7 @@ const pinia = createPinia();
 
 app.use(pinia);
 app.use(router);
+app.use(VueApexCharts);
 installVuetify(app);
 
 // Restore persisted auth and context state before the first route navigation

src/admin/src/types/api.ts

@@ -476,6 +476,25 @@ export interface FlagResponse {
   featureStateValue: string | null;
 }
 
+// ─── Feature Usage ─────────────────────────────────────────────────────────────
+
+export interface TopFeatureUsage {
+  featureId: number;
+  featureName: string;
+  count: number;
+}
+
+export interface DailyUsage {
+  date: string;
+  totalCount: number;
+  features: TopFeatureUsage[];
+}
+
+export interface DashboardUsageResponse {
+  topFeaturesLastDay: TopFeatureUsage[];
+  dailyUsage: DailyUsage[];
+}
+
 // ─── Errors ───────────────────────────────────────────────────────────────────
 
 export interface ApiValidationError {

src/admin/src/views/DashboardView.vue

@@ -71,6 +71,61 @@
       </v-col>
     </v-row>
 
+    <!-- Usage charts (requires environment) -->
+    <template v-if="contextStore.currentEnvironment">
+      <v-row class="mb-4">
+        <!-- Top 10 features last day -->
+        <v-col cols="12" md="6">
+          <v-card rounded="lg" data-testid="top-features-chart-card">
+            <v-card-item class="pb-0">
+              <v-card-title class="text-body-1 font-weight-medium">Top Features (Last Day)</v-card-title>
+              <v-card-subtitle class="text-caption">Most evaluated flags in the last 24 hours</v-card-subtitle>
+            </v-card-item>
+            <v-card-text class="pt-2">
+              <div v-if="isLoadingUsage" class="d-flex align-center justify-center" style="height:280px">
+                <v-progress-circular indeterminate color="primary" />
+              </div>
+              <div v-else-if="usageError" class="d-flex align-center justify-center text-medium-emphasis" style="height:280px">
+                <span class="text-caption">Failed to load usage data</span>
+              </div>
+              <div v-else-if="!usageData || usageData.topFeaturesLastDay.length === 0" class="d-flex align-center justify-center text-medium-emphasis" style="height:280px">
+                <div class="text-center">
+                  <v-icon size="36" color="medium-emphasis" class="mb-2">ri-bar-chart-line</v-icon>
+                  <p class="text-caption">No evaluations recorded yet</p>
+                </div>
+              </div>
+              <TopFeaturesChart v-else :data="usageData.topFeaturesLastDay" />
+            </v-card-text>
+          </v-card>
+        </v-col>
+
+        <!-- Usage by day -->
+        <v-col cols="12" md="6">
+          <v-card rounded="lg" data-testid="daily-usage-chart-card">
+            <v-card-item class="pb-0">
+              <v-card-title class="text-body-1 font-weight-medium">Evaluations by Day</v-card-title>
+              <v-card-subtitle class="text-caption">Hover a bar to see per-flag counts · Last 14 days</v-card-subtitle>
+            </v-card-item>
+            <v-card-text class="pt-2">
+              <div v-if="isLoadingUsage" class="d-flex align-center justify-center" style="height:280px">
+                <v-progress-circular indeterminate color="primary" />
+              </div>
+              <div v-else-if="usageError" class="d-flex align-center justify-center text-medium-emphasis" style="height:280px">
+                <span class="text-caption">Failed to load usage data</span>
+              </div>
+              <div v-else-if="!usageData || usageData.dailyUsage.length === 0" class="d-flex align-center justify-center text-medium-emphasis" style="height:280px">
+                <div class="text-center">
+                  <v-icon size="36" color="medium-emphasis" class="mb-2">ri-bar-chart-2-line</v-icon>
+                  <p class="text-caption">No evaluations recorded yet</p>
+                </div>
+              </div>
+              <DailyUsageChart v-else :data="usageData.dailyUsage" />
+            </v-card-text>
+          </v-card>
+        </v-col>
+      </v-row>
+    </template>
+
     <!-- Quick-nav cards -->
     <v-row v-if="contextStore.currentProject">
       <v-col
@@ -124,10 +179,38 @@
 </template>
 
 <script setup lang="ts">
+import { ref, watch } from 'vue';
 import { useContextStore } from '@/stores/context';
+import { getUsageDashboard } from '@/api/usage';
+import TopFeaturesChart from '@/components/dashboard/TopFeaturesChart.vue';
+import DailyUsageChart from '@/components/dashboard/DailyUsageChart.vue';
+import type { DashboardUsageResponse } from '@/types/api';
 
 const contextStore = useContextStore();
 
+const usageData = ref<DashboardUsageResponse | null>(null);
+const isLoadingUsage = ref(false);
+const usageError = ref(false);
+
+async function loadUsage(): Promise<void> {
+  const envId = contextStore.currentEnvironment?.id;
+  if (!envId) {
+    usageData.value = null;
+    return;
+  }
+  isLoadingUsage.value = true;
+  usageError.value = false;
+  try {
+    usageData.value = await getUsageDashboard(envId);
+  } catch {
+    usageError.value = true;
+  } finally {
+    isLoadingUsage.value = false;
+  }
+}
+
+watch(() => contextStore.currentEnvironment, loadUsage, { immediate: true });
+
 const sections = [
   {
     label: 'Features',

src/admin/src/views/IdentitiesView.vue

@@ -91,6 +91,7 @@
       v-model="showDetail"
       :identity="selectedIdentity"
       @deleted="onIdentityDeleted"
+      @updated="onIdentityUpdated"
     />
 
     <!-- Create identity dialog -->
@@ -246,6 +247,12 @@ function onCreateDialogClosed(): void {
   createError.value = null;
 }
 
+function onIdentityUpdated(updated: IdentityResponse): void {
+  const idx = identities.value.findIndex((i) => i.id === updated.id);
+  if (idx >= 0) identities.value[idx] = updated;
+  selectedIdentity.value = updated;
+}
+
 function onIdentityDeleted(identityId: number): void {
   identities.value = identities.value.filter((i) => i.id !== identityId);
   showDetail.value = false;

src/api/MicCheck.Api/Data/Configurations/FeatureUsageDailyConfiguration.cs

@@ -0,0 +1,19 @@
+using MicCheck.Api.Features;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace MicCheck.Api.Data.Configurations;
+
+public class FeatureUsageDailyConfiguration : IEntityTypeConfiguration<FeatureUsageDaily>
+{
+    public void Configure(EntityTypeBuilder<FeatureUsageDaily> builder)
+    {
+        builder.HasKey(u => u.Id);
+        builder.Property(u => u.FeatureName).HasMaxLength(150).IsRequired();
+        builder.Property(u => u.UpdatedAt).IsRequired();
+        builder.Property(u => u.Count).IsRequired();
+
+        builder.HasIndex(u => new { u.EnvironmentId, u.FeatureId, u.UsageDate }).IsUnique();
+        builder.HasIndex(u => new { u.EnvironmentId, u.UsageDate });
+    }
+}

src/api/MicCheck.Api/Data/MicCheckDbContext.cs

@@ -37,6 +37,7 @@ public class MicCheckDbContext : DbContext
     public DbSet<User> Users => Set<User>();
     public DbSet<RefreshToken> RefreshTokens => Set<RefreshToken>();
     public DbSet<UserProjectPermission> UserProjectPermissions => Set<UserProjectPermission>();
+    public DbSet<FeatureUsageDaily> FeatureUsageDaily => Set<FeatureUsageDaily>();
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
         => modelBuilder.ApplyConfigurationsFromAssembly(typeof(MicCheckDbContext).Assembly);

src/api/MicCheck.Api/Features/FeatureEvaluationService.cs

@@ -8,7 +8,8 @@ namespace MicCheck.Api.Features;
 public class FeatureEvaluationService(
     MicCheckDbContext db,
     SegmentEvaluator segmentEvaluator,
-    FlagCache flagCache)
+    FlagCache flagCache,
+    FeatureUsageMetrics usageMetrics)
 {
     public async Task<IReadOnlyList<FeatureStateResult>> EvaluateForEnvironmentAsync(
         int environmentId, CancellationToken ct = default)
@@ -32,6 +33,10 @@ public class FeatureEvaluationService(
         ).ToListAsync(ct);
 
         flagCache.Set(environmentId, results);
+
+        foreach (var r in results)
+            usageMetrics.RecordEvaluation(environmentId, r.Feature.Id, r.Feature.Name);
+
         return results;
     }
 
@@ -134,6 +139,9 @@ public class FeatureEvaluationService(
             }
         }
 
+        foreach (var r in results)
+            usageMetrics.RecordEvaluation(environmentId, r.Feature.Id, r.Feature.Name);
+
         return results;
     }
 }

src/api/MicCheck.Api/Features/FeatureUsageBucketKey.cs

@@ -0,0 +1,3 @@
+namespace MicCheck.Api.Features;
+
+public record struct FeatureUsageBucketKey(int EnvironmentId, int FeatureId, string FeatureName, DateOnly UsageDate);

src/api/MicCheck.Api/Features/FeatureUsageController.cs

@@ -0,0 +1,32 @@
+using MicCheck.Api.Common.Security.Authorization;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.RateLimiting;
+using Microsoft.Extensions.Caching.Memory;
+
+namespace MicCheck.Api.Features;
+
+[ApiController]
+[Route("api/v1/environments/{environmentId}/usage")]
+[Authorize(Policy = AuthorizationPolicies.AdminApiAccess)]
+[EnableRateLimiting("AdminApi")]
+public class FeatureUsageController(FeatureUsageQueryService queryService, IMemoryCache cache) : ControllerBase
+{
+    [HttpGet]
+    public async Task<ActionResult<DashboardUsageResponse>> GetDashboardUsage(
+        int environmentId,
+        [FromQuery] int days = 14,
+        CancellationToken ct = default)
+    {
+        days = Math.Clamp(days, 1, 90);
+        var cacheKey = $"usage-dashboard:{environmentId}:{days}";
+
+        if (cache.TryGetValue(cacheKey, out DashboardUsageResponse? cached))
+            return Ok(cached);
+
+        var result = await queryService.GetDashboardUsageAsync(environmentId, days, ct);
+
+        cache.Set(cacheKey, result, TimeSpan.FromSeconds(180));
+        return Ok(result);
+    }
+}

src/api/MicCheck.Api/Features/FeatureUsageDaily.cs

@@ -0,0 +1,12 @@
+namespace MicCheck.Api.Features;
+
+public class FeatureUsageDaily
+{
+    public int Id { get; init; }
+    public int EnvironmentId { get; init; }
+    public int FeatureId { get; init; }
+    public required string FeatureName { get; set; }
+    public DateOnly UsageDate { get; init; }
+    public long Count { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+}

src/api/MicCheck.Api/Features/FeatureUsageFlushBackgroundService.cs

@@ -0,0 +1,60 @@
+using MicCheck.Api.Data;
+using Microsoft.EntityFrameworkCore;
+
+namespace MicCheck.Api.Features;
+
+public class FeatureUsageFlushBackgroundService(
+    FeatureUsageMetrics metrics,
+    IServiceScopeFactory scopeFactory,
+    ILogger<FeatureUsageFlushBackgroundService> logger) : BackgroundService
+{
+    private static readonly TimeSpan FlushInterval = TimeSpan.FromSeconds(30);
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        using var timer = new PeriodicTimer(FlushInterval);
+        while (await timer.WaitForNextTickAsync(stoppingToken))
+        {
+            await FlushAsync(stoppingToken);
+        }
+    }
+
+    public override async Task StopAsync(CancellationToken cancellationToken)
+    {
+        await base.StopAsync(cancellationToken);
+        await FlushAsync(CancellationToken.None);
+    }
+
+    private async Task FlushAsync(CancellationToken ct)
+    {
+        var deltas = metrics.DrainAccumulated();
+        if (deltas.Count == 0)
+            return;
+
+        var updatedAt = DateTimeOffset.UtcNow;
+
+        try
+        {
+            await using var scope = scopeFactory.CreateAsyncScope();
+            var db = scope.ServiceProvider.GetRequiredService<MicCheckDbContext>();
+
+            foreach (var (key, count) in deltas)
+            {
+                await db.Database.ExecuteSqlAsync(
+                    $"""
+                    INSERT INTO "FeatureUsageDaily" ("EnvironmentId", "FeatureId", "FeatureName", "UsageDate", "Count", "UpdatedAt")
+                    VALUES ({key.EnvironmentId}, {key.FeatureId}, {key.FeatureName}, {key.UsageDate}, {count}, {updatedAt})
+                    ON CONFLICT ("EnvironmentId", "FeatureId", "UsageDate")
+                    DO UPDATE SET "Count" = "FeatureUsageDaily"."Count" + EXCLUDED."Count",
+                                  "FeatureName" = EXCLUDED."FeatureName",
+                                  "UpdatedAt" = EXCLUDED."UpdatedAt"
+                    """,
+                    ct);
+            }
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to flush feature usage data ({BucketCount} buckets)", deltas.Count);
+        }
+    }
+}

src/api/MicCheck.Api/Features/FeatureUsageMetrics.cs

@@ -0,0 +1,35 @@
+using System.Collections.Concurrent;
+using System.Diagnostics.Metrics;
+
+namespace MicCheck.Api.Features;
+
+public class FeatureUsageMetrics : IDisposable
+{
+    private readonly Meter _meter;
+    private readonly Counter<long> _evaluationCounter;
+    private ConcurrentDictionary<FeatureUsageBucketKey, long> _accumulator = new();
+
+    public FeatureUsageMetrics(IMeterFactory meterFactory)
+    {
+        _meter = meterFactory.Create("MicCheck.FeatureUsage");
+        _evaluationCounter = _meter.CreateCounter<long>("miccheck.feature.evaluations", description: "Number of feature flag evaluations");
+    }
+
+    public void RecordEvaluation(int environmentId, int featureId, string featureName)
+    {
+        _evaluationCounter.Add(1,
+            new KeyValuePair<string, object?>("environment.id", environmentId),
+            new KeyValuePair<string, object?>("feature.id", featureId));
+
+        var key = new FeatureUsageBucketKey(environmentId, featureId, featureName, DateOnly.FromDateTime(DateTime.UtcNow));
+        _accumulator.AddOrUpdate(key, 1L, (_, existing) => existing + 1);
+    }
+
+    public IReadOnlyDictionary<FeatureUsageBucketKey, long> DrainAccumulated()
+    {
+        var drained = Interlocked.Exchange(ref _accumulator, new ConcurrentDictionary<FeatureUsageBucketKey, long>());
+        return drained;
+    }
+
+    public void Dispose() => _meter.Dispose();
+}

src/api/MicCheck.Api/Features/FeatureUsageQueryService.cs

@@ -0,0 +1,42 @@
+using MicCheck.Api.Data;
+using Microsoft.EntityFrameworkCore;
+
+namespace MicCheck.Api.Features;
+
+public class FeatureUsageQueryService(MicCheckDbContext db)
+{
+    public async Task<DashboardUsageResponse> GetDashboardUsageAsync(int environmentId, int days, CancellationToken ct = default)
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        var windowStart = today.AddDays(-days);
+        var yesterday = today.AddDays(-1);
+
+        var rows = await db.FeatureUsageDaily
+            .Where(u => u.EnvironmentId == environmentId && u.UsageDate >= windowStart)
+            .ToListAsync(ct);
+
+        var topFeaturesLastDay = rows
+            .Where(u => u.UsageDate >= yesterday)
+            .GroupBy(u => new { u.FeatureId, u.FeatureName })
+            .Select(g => new TopFeatureUsage(g.Key.FeatureId, g.Key.FeatureName, g.Sum(u => u.Count)))
+            .OrderByDescending(t => t.Count)
+            .Take(10)
+            .ToList();
+
+        var dailyUsage = rows
+            .GroupBy(u => u.UsageDate)
+            .OrderBy(g => g.Key)
+            .Select(g =>
+            {
+                var features = g
+                    .GroupBy(u => new { u.FeatureId, u.FeatureName })
+                    .Select(fg => new TopFeatureUsage(fg.Key.FeatureId, fg.Key.FeatureName, fg.Sum(u => u.Count)))
+                    .OrderByDescending(f => f.Count)
+                    .ToList();
+                return new DailyUsage(g.Key, features.Sum(f => f.Count), features);
+            })
+            .ToList();
+
+        return new DashboardUsageResponse(topFeaturesLastDay, dailyUsage);
+    }
+}

src/api/MicCheck.Api/Features/FeatureUsageResponses.cs

@@ -0,0 +1,9 @@
+namespace MicCheck.Api.Features;
+
+public record TopFeatureUsage(int FeatureId, string FeatureName, long Count);
+
+public record DailyUsage(DateOnly Date, long TotalCount, IReadOnlyList<TopFeatureUsage> Features);
+
+public record DashboardUsageResponse(
+    IReadOnlyList<TopFeatureUsage> TopFeaturesLastDay,
+    IReadOnlyList<DailyUsage> DailyUsage);

src/api/MicCheck.Api/Identities/UpsertTraitRequest.cs

@@ -1,3 +1,3 @@
 namespace MicCheck.Api.Identities;
 
-public record UpsertTraitRequest(string Key, string Value);
+public record UpsertTraitRequest(string Value);

src/api/MicCheck.Api/Migrations/20260617194113_AddFeatureUsageDaily.Designer.cs

@@ -0,0 +1,979 @@
+// <auto-generated />
+using System;
+using MicCheck.Api.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace MicCheck.Api.Migrations
+{
+    [DbContext(typeof(MicCheckDbContext))]
+    [Migration("20260617194113_AddFeatureUsageDaily")]
+    partial class AddFeatureUsageDaily
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "10.0.5")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("FeatureTags", b =>
+                {
+                    b.Property<int>("FeatureId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("TagsId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("FeatureId", "TagsId");
+
+                    b.HasIndex("TagsId");
+
+                    b.ToTable("FeatureTags");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Audit.AuditLog", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("Action")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<int?>("ActorUserId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Changes")
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int?>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("OrganizationId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("ProjectId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ResourceId")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("ResourceType")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("OrganizationId", "CreatedAt");
+
+                    b.ToTable("AuditLogs");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Common.Security.ApiKeys.ApiKey", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset?>("ExpiresAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("IsActive")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Key")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("OrganizationId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Prefix")
+                        .IsRequired()
+                        .HasMaxLength(8)
+                        .HasColumnType("character varying(8)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Key")
+                        .IsUnique();
+
+                    b.HasIndex("OrganizationId");
+
+                    b.ToTable("ApiKeys");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Common.Security.Authorization.UserProjectPermission", b =>
+                {
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("ProjectId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsAdmin")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Permissions")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("UserId", "ProjectId");
+
+                    b.ToTable("UserProjectPermissions");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Environments.Environment", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("ApiKey")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("ProjectId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ApiKey")
+                        .IsUnique();
+
+                    b.HasIndex("ProjectId");
+
+                    b.ToTable("Environments");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.Feature", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("DefaultEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Description")
+                        .HasMaxLength(2000)
+                        .HasColumnType("character varying(2000)");
+
+                    b.Property<string>("InitialValue")
+                        .HasMaxLength(20000)
+                        .HasColumnType("character varying(20000)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(150)
+                        .HasColumnType("character varying(150)");
+
+                    b.Property<int>("ProjectId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ProjectId", "Name")
+                        .IsUnique();
+
+                    b.ToTable("Features");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.FeatureSegment", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<int>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("FeatureId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Priority")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SegmentId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("FeatureSegments");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.FeatureState", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("Enabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("FeatureId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("FeatureSegmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("IdentityId")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Value")
+                        .HasMaxLength(20000)
+                        .HasColumnType("character varying(20000)");
+
+                    b.Property<int>("Version")
+                        .IsConcurrencyToken()
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EnvironmentId");
+
+                    b.HasIndex("FeatureSegmentId")
+                        .IsUnique();
+
+                    b.HasIndex("IdentityId");
+
+                    b.HasIndex("FeatureId", "EnvironmentId", "IdentityId")
+                        .IsUnique();
+
+                    b.ToTable("FeatureStates");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.FeatureUsageDaily", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<long>("Count")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("FeatureId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("FeatureName")
+                        .IsRequired()
+                        .HasMaxLength(150)
+                        .HasColumnType("character varying(150)");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateOnly>("UsageDate")
+                        .HasColumnType("date");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EnvironmentId", "UsageDate");
+
+                    b.HasIndex("EnvironmentId", "FeatureId", "UsageDate")
+                        .IsUnique();
+
+                    b.ToTable("FeatureUsageDaily");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.Tag", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("Color")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<string>("Label")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("ProjectId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ProjectId");
+
+                    b.ToTable("Tags");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Identities.Identity", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Identifier")
+                        .IsRequired()
+                        .HasMaxLength(2000)
+                        .HasColumnType("character varying(2000)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EnvironmentId", "Identifier")
+                        .IsUnique();
+
+                    b.ToTable("Identities");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Identities.IdentityTrait", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<int>("IdentityId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Key")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<string>("Value")
+                        .IsRequired()
+                        .HasMaxLength(2000)
+                        .HasColumnType("character varying(2000)");
+
+                    b.Property<int>("ValueType")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("IdentityId", "Key")
+                        .IsUnique();
+
+                    b.ToTable("IdentityTraits");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Organizations.Organization", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("InviteToken")
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("InviteToken")
+                        .IsUnique()
+                        .HasFilter("\"InviteToken\" IS NOT NULL");
+
+                    b.ToTable("Organizations");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Organizations.OrganizationUser", b =>
+                {
+                    b.Property<int>("OrganizationId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsPrimary")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(false);
+
+                    b.Property<int>("Role")
+                        .HasColumnType("integer");
+
+                    b.HasKey("OrganizationId", "UserId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("OrganizationUsers");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Projects.Project", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("HideDisabledFlags")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("OrganizationId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("OrganizationId");
+
+                    b.ToTable("Projects");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.Segment", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("ProjectId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ProjectId");
+
+                    b.ToTable("Segments");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.SegmentCondition", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<int>("Operator")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Property")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<int>("RuleId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Value")
+                        .IsRequired()
+                        .HasMaxLength(1000)
+                        .HasColumnType("character varying(1000)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("RuleId");
+
+                    b.ToTable("SegmentConditions");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.SegmentRule", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<int?>("ParentRuleId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SegmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ParentRuleId");
+
+                    b.HasIndex("SegmentId");
+
+                    b.ToTable("SegmentRules");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Users.RefreshToken", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset>("ExpiresAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("IsRevoked")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Token")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Token")
+                        .IsUnique();
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("RefreshTokens");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Users.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.Property<string>("FirstName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<bool>("IsActive")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsTwoFactorEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<DateTimeOffset?>("LastLoginAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("LastName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email")
+                        .IsUnique();
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Webhooks.Webhook", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("Enabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<int?>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("OrganizationId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Scope")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Secret")
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<string>("Url")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EnvironmentId");
+
+                    b.ToTable("Webhooks");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Webhooks.WebhookDeliveryLog", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<int>("AttemptNumber")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset>("AttemptedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<TimeSpan>("Duration")
+                        .HasColumnType("interval");
+
+                    b.Property<string>("ErrorMessage")
+                        .HasColumnType("text");
+
+                    b.Property<string>("EventType")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("PayloadJson")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("ResponseBody")
+                        .HasColumnType("text");
+
+                    b.Property<int?>("ResponseStatusCode")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("Success")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("WebhookId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("WebhookId");
+
+                    b.ToTable("WebhookDeliveryLogs");
+                });
+
+            modelBuilder.Entity("FeatureTags", b =>
+                {
+                    b.HasOne("MicCheck.Api.Features.Feature", null)
+                        .WithMany()
+                        .HasForeignKey("FeatureId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MicCheck.Api.Features.Tag", null)
+                        .WithMany()
+                        .HasForeignKey("TagsId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Common.Security.ApiKeys.ApiKey", b =>
+                {
+                    b.HasOne("MicCheck.Api.Organizations.Organization", null)
+                        .WithMany("ApiKeys")
+                        .HasForeignKey("OrganizationId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Environments.Environment", b =>
+                {
+                    b.HasOne("MicCheck.Api.Projects.Project", null)
+                        .WithMany("Environments")
+                        .HasForeignKey("ProjectId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.Feature", b =>
+                {
+                    b.HasOne("MicCheck.Api.Projects.Project", null)
+                        .WithMany("Features")
+                        .HasForeignKey("ProjectId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.FeatureState", b =>
+                {
+                    b.HasOne("MicCheck.Api.Environments.Environment", null)
+                        .WithMany("FeatureStates")
+                        .HasForeignKey("EnvironmentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MicCheck.Api.Features.Feature", null)
+                        .WithMany("FeatureStates")
+                        .HasForeignKey("FeatureId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MicCheck.Api.Features.FeatureSegment", null)
+                        .WithOne("FeatureState")
+                        .HasForeignKey("MicCheck.Api.Features.FeatureState", "FeatureSegmentId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("MicCheck.Api.Identities.Identity", null)
+                        .WithMany("FeatureStateOverrides")
+                        .HasForeignKey("IdentityId")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.Tag", b =>
+                {
+                    b.HasOne("MicCheck.Api.Projects.Project", null)
+                        .WithMany()
+                        .HasForeignKey("ProjectId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Identities.IdentityTrait", b =>
+                {
+                    b.HasOne("MicCheck.Api.Identities.Identity", null)
+                        .WithMany("Traits")
+                        .HasForeignKey("IdentityId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Organizations.OrganizationUser", b =>
+                {
+                    b.HasOne("MicCheck.Api.Organizations.Organization", null)
+                        .WithMany("Members")
+                        .HasForeignKey("OrganizationId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MicCheck.Api.Users.User", "User")
+                        .WithMany("Organizations")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Projects.Project", b =>
+                {
+                    b.HasOne("MicCheck.Api.Organizations.Organization", null)
+                        .WithMany("Projects")
+                        .HasForeignKey("OrganizationId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.Segment", b =>
+                {
+                    b.HasOne("MicCheck.Api.Projects.Project", null)
+                        .WithMany("Segments")
+                        .HasForeignKey("ProjectId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.SegmentCondition", b =>
+                {
+                    b.HasOne("MicCheck.Api.Segments.SegmentRule", null)
+                        .WithMany("Conditions")
+                        .HasForeignKey("RuleId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.SegmentRule", b =>
+                {
+                    b.HasOne("MicCheck.Api.Segments.SegmentRule", null)
+                        .WithMany("ChildRules")
+                        .HasForeignKey("ParentRuleId")
+                        .OnDelete(DeleteBehavior.NoAction);
+
+                    b.HasOne("MicCheck.Api.Segments.Segment", null)
+                        .WithMany("Rules")
+                        .HasForeignKey("SegmentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Users.RefreshToken", b =>
+                {
+                    b.HasOne("MicCheck.Api.Users.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Environments.Environment", b =>
+                {
+                    b.Navigation("FeatureStates");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.Feature", b =>
+                {
+                    b.Navigation("FeatureStates");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Features.FeatureSegment", b =>
+                {
+                    b.Navigation("FeatureState");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Identities.Identity", b =>
+                {
+                    b.Navigation("FeatureStateOverrides");
+
+                    b.Navigation("Traits");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Organizations.Organization", b =>
+                {
+                    b.Navigation("ApiKeys");
+
+                    b.Navigation("Members");
+
+                    b.Navigation("Projects");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Projects.Project", b =>
+                {
+                    b.Navigation("Environments");
+
+                    b.Navigation("Features");
+
+                    b.Navigation("Segments");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.Segment", b =>
+                {
+                    b.Navigation("Rules");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Segments.SegmentRule", b =>
+                {
+                    b.Navigation("ChildRules");
+
+                    b.Navigation("Conditions");
+                });
+
+            modelBuilder.Entity("MicCheck.Api.Users.User", b =>
+                {
+                    b.Navigation("Organizations");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

src/api/MicCheck.Api/Migrations/20260617194113_AddFeatureUsageDaily.cs

@@ -0,0 +1,52 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace MicCheck.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddFeatureUsageDaily : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "FeatureUsageDaily",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    EnvironmentId = table.Column<int>(type: "integer", nullable: false),
+                    FeatureId = table.Column<int>(type: "integer", nullable: false),
+                    FeatureName = table.Column<string>(type: "character varying(150)", maxLength: 150, nullable: false),
+                    UsageDate = table.Column<DateOnly>(type: "date", nullable: false),
+                    Count = table.Column<long>(type: "bigint", nullable: false),
+                    UpdatedAt = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_FeatureUsageDaily", x => x.Id);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_FeatureUsageDaily_EnvironmentId_FeatureId_UsageDate",
+                table: "FeatureUsageDaily",
+                columns: new[] { "EnvironmentId", "FeatureId", "UsageDate" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_FeatureUsageDaily_EnvironmentId_UsageDate",
+                table: "FeatureUsageDaily",
+                columns: new[] { "EnvironmentId", "UsageDate" });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "FeatureUsageDaily");
+        }
+    }
+}

src/api/MicCheck.Api/Migrations/MicCheckDbContextModelSnapshot.cs

@@ -302,6 +302,44 @@ namespace MicCheck.Api.Migrations
                     b.ToTable("FeatureStates");
                 });
 
+            modelBuilder.Entity("MicCheck.Api.Features.FeatureUsageDaily", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<long>("Count")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("EnvironmentId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("FeatureId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("FeatureName")
+                        .IsRequired()
+                        .HasMaxLength(150)
+                        .HasColumnType("character varying(150)");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateOnly>("UsageDate")
+                        .HasColumnType("date");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EnvironmentId", "UsageDate");
+
+                    b.HasIndex("EnvironmentId", "FeatureId", "UsageDate")
+                        .IsUnique();
+
+                    b.ToTable("FeatureUsageDaily");
+                });
+
             modelBuilder.Entity("MicCheck.Api.Features.Tag", b =>
                 {
                     b.Property<int>("Id")

src/api/MicCheck.Api/Program.cs

@@ -109,6 +109,7 @@ try
     });
 
     builder.Services.AddMemoryCache();
+    builder.Services.AddMetrics();
 
     builder.Services.AddScoped<ITokenService, TokenService>();
     builder.Services.AddScoped<AuthService>();
@@ -138,6 +139,9 @@ try
     builder.Services.AddSingleton<WebhookQueue>();
     builder.Services.AddHostedService<WebhookBackgroundService>();
     builder.Services.AddHostedService<WebhookRetryBackgroundService>();
+    builder.Services.AddSingleton<FeatureUsageMetrics>();
+    builder.Services.AddScoped<FeatureUsageQueryService>();
+    builder.Services.AddHostedService<FeatureUsageFlushBackgroundService>();
     builder.Services.AddHttpClient("Webhooks", client =>
         client.DefaultRequestHeaders.Add("User-Agent", "MicCheck-Webhook/1.0"));
 

tests/api/MicCheck.Api.Tests.Unit/Features/FeatureEvaluationServiceTests.cs

@@ -1,9 +1,11 @@
+using System.Diagnostics.Metrics;
 using MicCheck.Api.Data;
 using MicCheck.Api.Features;
 using MicCheck.Api.Identities;
 using MicCheck.Api.Segments;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Caching.Memory;
+using Moq;
 using NUnit.Framework;
 using AppEnvironment = MicCheck.Api.Environments.Environment;
 
@@ -14,6 +16,7 @@ public class FeatureEvaluationServiceTests
 {
     private MicCheckDbContext _db = null!;
     private FeatureEvaluationService _service = null!;
+    private FeatureUsageMetrics _usageMetrics = null!;
     private const int EnvironmentId = 1;
     private const int ProjectId = 1;
 
@@ -25,14 +28,22 @@ public class FeatureEvaluationServiceTests
             .Options;
         _db = new MicCheckDbContext(options);
 
+        var meterFactory = new Mock<IMeterFactory>();
+        meterFactory.Setup(f => f.Create(It.IsAny<MeterOptions>())).Returns(new Meter("test"));
+        _usageMetrics = new FeatureUsageMetrics(meterFactory.Object);
+
         var cache = new FlagCache(new MemoryCache(new MemoryCacheOptions()));
-        _service = new FeatureEvaluationService(_db, new SegmentEvaluator(), cache);
+        _service = new FeatureEvaluationService(_db, new SegmentEvaluator(), cache, _usageMetrics);
 
         SeedBaseData();
     }
 
     [TearDown]
-    public void TearDown() => _db.Dispose();
+    public void TearDown()
+    {
+        _db.Dispose();
+        _usageMetrics.Dispose();
+    }
 
     private void SeedBaseData()
     {

tests/api/MicCheck.Api.Tests.Unit/Features/FeatureUsageMetricsTests.cs

@@ -0,0 +1,80 @@
+using System.Diagnostics.Metrics;
+using MicCheck.Api.Features;
+using Moq;
+using NUnit.Framework;
+
+namespace MicCheck.Api.Tests.Unit.Features;
+
+[TestFixture]
+public class FeatureUsageMetricsTests
+{
+    private FeatureUsageMetrics _metrics = null!;
+
+    [SetUp]
+    public void SetUp()
+    {
+        var meterFactory = new Mock<IMeterFactory>();
+        meterFactory.Setup(f => f.Create(It.IsAny<MeterOptions>())).Returns(new Meter("test"));
+        _metrics = new FeatureUsageMetrics(meterFactory.Object);
+    }
+
+    [TearDown]
+    public void TearDown() => _metrics.Dispose();
+
+    [Test]
+    public void WhenRecordingEvaluations_ThenAccumulatorIncrementsByFeatureAndEnvironment()
+    {
+        _metrics.RecordEvaluation(environmentId: 1, featureId: 10, featureName: "dark_mode");
+        _metrics.RecordEvaluation(environmentId: 1, featureId: 10, featureName: "dark_mode");
+        _metrics.RecordEvaluation(environmentId: 1, featureId: 20, featureName: "beta");
+        _metrics.RecordEvaluation(environmentId: 2, featureId: 10, featureName: "dark_mode");
+
+        var drained = _metrics.DrainAccumulated();
+
+        Assert.That(drained, Has.Count.EqualTo(3));
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        Assert.That(drained[new FeatureUsageBucketKey(1, 10, "dark_mode", today)], Is.EqualTo(2));
+        Assert.That(drained[new FeatureUsageBucketKey(1, 20, "beta", today)], Is.EqualTo(1));
+        Assert.That(drained[new FeatureUsageBucketKey(2, 10, "dark_mode", today)], Is.EqualTo(1));
+    }
+
+    [Test]
+    public void WhenDrainCalled_ThenAccumulatorIsResetToEmpty()
+    {
+        _metrics.RecordEvaluation(environmentId: 1, featureId: 10, featureName: "dark_mode");
+
+        _metrics.DrainAccumulated();
+        var secondDrain = _metrics.DrainAccumulated();
+
+        Assert.That(secondDrain, Is.Empty);
+    }
+
+    [Test]
+    public void WhenNothingRecorded_ThenDrainReturnsEmptyDictionary()
+    {
+        var drained = _metrics.DrainAccumulated();
+
+        Assert.That(drained, Is.Empty);
+    }
+
+    [Test]
+    public void WhenRecordingConcurrently_ThenCountsAreAccurateAndNoDataLost()
+    {
+        const int threads = 8;
+        const int recordsPerThread = 100;
+
+        var tasks = Enumerable.Range(0, threads).Select(_ =>
+            Task.Run(() =>
+            {
+                for (var i = 0; i < recordsPerThread; i++)
+                    _metrics.RecordEvaluation(environmentId: 1, featureId: 1, featureName: "concurrent_flag");
+            })).ToArray();
+
+        Task.WaitAll(tasks);
+
+        var drained = _metrics.DrainAccumulated();
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+
+        Assert.That(drained[new FeatureUsageBucketKey(1, 1, "concurrent_flag", today)], Is.EqualTo(threads * recordsPerThread));
+    }
+}

tests/api/MicCheck.Api.Tests.Unit/Features/FeatureUsageQueryServiceTests.cs

@@ -0,0 +1,138 @@
+using MicCheck.Api.Data;
+using MicCheck.Api.Features;
+using Microsoft.EntityFrameworkCore;
+using NUnit.Framework;
+
+namespace MicCheck.Api.Tests.Unit.Features;
+
+[TestFixture]
+public class FeatureUsageQueryServiceTests
+{
+    private MicCheckDbContext _db = null!;
+    private FeatureUsageQueryService _service = null!;
+    private const int EnvironmentId = 1;
+
+    [SetUp]
+    public void SetUp()
+    {
+        var options = new DbContextOptionsBuilder<MicCheckDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .Options;
+        _db = new MicCheckDbContext(options);
+        _service = new FeatureUsageQueryService(_db);
+    }
+
+    [TearDown]
+    public void TearDown() => _db.Dispose();
+
+    private void SeedUsage(int environmentId, int featureId, string featureName, DateOnly date, long count)
+    {
+        _db.FeatureUsageDaily.Add(new FeatureUsageDaily
+        {
+            EnvironmentId = environmentId,
+            FeatureId = featureId,
+            FeatureName = featureName,
+            UsageDate = date,
+            Count = count,
+            UpdatedAt = DateTimeOffset.UtcNow
+        });
+        _db.SaveChanges();
+    }
+
+    [Test]
+    public async Task WhenNoUsageData_ThenEmptyCollectionsAreReturned()
+    {
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 14);
+
+        Assert.That(result.TopFeaturesLastDay, Is.Empty);
+        Assert.That(result.DailyUsage, Is.Empty);
+    }
+
+    [Test]
+    public async Task WhenMultipleFeaturesEvaluatedToday_ThenTopFeaturesLastDayOrdersByCountDescending()
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        SeedUsage(EnvironmentId, featureId: 1, "feature_a", today, count: 50);
+        SeedUsage(EnvironmentId, featureId: 2, "feature_b", today, count: 200);
+        SeedUsage(EnvironmentId, featureId: 3, "feature_c", today, count: 10);
+
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 1);
+
+        Assert.That(result.TopFeaturesLastDay, Has.Count.EqualTo(3));
+        Assert.That(result.TopFeaturesLastDay[0].FeatureName, Is.EqualTo("feature_b"));
+        Assert.That(result.TopFeaturesLastDay[0].Count, Is.EqualTo(200));
+        Assert.That(result.TopFeaturesLastDay[1].FeatureName, Is.EqualTo("feature_a"));
+        Assert.That(result.TopFeaturesLastDay[2].FeatureName, Is.EqualTo("feature_c"));
+    }
+
+    [Test]
+    public async Task WhenMoreThanTenFeatures_ThenTopFeaturesLastDayLimitsToTen()
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        for (var i = 1; i <= 15; i++)
+            SeedUsage(EnvironmentId, featureId: i, $"feature_{i}", today, count: i * 10L);
+
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 1);
+
+        Assert.That(result.TopFeaturesLastDay, Has.Count.EqualTo(10));
+    }
+
+    [Test]
+    public async Task WhenUsageSpansMultipleDays_ThenDailyUsageGroupsByDateAscending()
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        SeedUsage(EnvironmentId, featureId: 1, "flag", today.AddDays(-2), count: 30);
+        SeedUsage(EnvironmentId, featureId: 1, "flag", today.AddDays(-1), count: 50);
+        SeedUsage(EnvironmentId, featureId: 1, "flag", today, count: 20);
+
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 7);
+
+        Assert.That(result.DailyUsage, Has.Count.EqualTo(3));
+        Assert.That(result.DailyUsage[0].Date, Is.EqualTo(today.AddDays(-2)));
+        Assert.That(result.DailyUsage[0].TotalCount, Is.EqualTo(30));
+        Assert.That(result.DailyUsage[1].TotalCount, Is.EqualTo(50));
+        Assert.That(result.DailyUsage[2].TotalCount, Is.EqualTo(20));
+    }
+
+    [Test]
+    public async Task WhenHoveringADay_ThenDailyUsageIncludesPerFeatureBreakdownOrderedByCount()
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        SeedUsage(EnvironmentId, featureId: 1, "feature_a", today, count: 10);
+        SeedUsage(EnvironmentId, featureId: 2, "feature_b", today, count: 40);
+
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 1);
+
+        var day = result.DailyUsage.Single();
+        Assert.That(day.TotalCount, Is.EqualTo(50));
+        Assert.That(day.Features, Has.Count.EqualTo(2));
+        Assert.That(day.Features[0].FeatureName, Is.EqualTo("feature_b"));
+        Assert.That(day.Features[0].Count, Is.EqualTo(40));
+        Assert.That(day.Features[1].FeatureName, Is.EqualTo("feature_a"));
+    }
+
+    [Test]
+    public async Task WhenUsageExistsOutsideDaysWindow_ThenOldDataIsExcluded()
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        SeedUsage(EnvironmentId, featureId: 1, "flag", today.AddDays(-30), count: 999);
+        SeedUsage(EnvironmentId, featureId: 1, "flag", today.AddDays(-3), count: 5);
+
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 7);
+
+        Assert.That(result.DailyUsage, Has.Count.EqualTo(1));
+        Assert.That(result.DailyUsage[0].TotalCount, Is.EqualTo(5));
+    }
+
+    [Test]
+    public async Task WhenOtherEnvironmentHasUsage_ThenItIsNotIncludedInResults()
+    {
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        SeedUsage(environmentId: 99, featureId: 1, "flag", today, count: 100);
+
+        var result = await _service.GetDashboardUsageAsync(EnvironmentId, days: 7);
+
+        Assert.That(result.TopFeaturesLastDay, Is.Empty);
+        Assert.That(result.DailyUsage, Is.Empty);
+    }
+}