diff --git a/backend/app/api/deps.py b/backend/app/api/deps.py
index 4cdd8a94..f17858de 100644
--- a/backend/app/api/deps.py
+++ b/backend/app/api/deps.py
@@ -4,6 +4,7 @@ from fastapi import Depends, HTTPException, Request, status
 from fastapi.security import OAuth2PasswordBearer
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
+import sentry_sdk
 
 from app.core.database import get_db
 from app.core.security import decode_token
@@ -92,6 +93,9 @@ async def get_current_active_user(
                 detail="password_change_required"
             )
 
+    # Set Sentry user context for error attribution
+    sentry_sdk.set_user({"id": str(current_user.id), "email": current_user.email})
+
     # Lightweight trial expiry check
     if current_user.account_id:
         from app.models.subscription import Subscription
diff --git a/backend/app/main.py b/backend/app/main.py
index ccf3feb8..61e6a4e7 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -17,6 +17,8 @@ if settings.SENTRY_DSN:
         environment="development" if settings.DEBUG else "production",
         send_default_pii=True,
         traces_sample_rate=1.0 if settings.DEBUG else 0.2,
+        # Profiling — included in free plan
+        profiles_sample_rate=1.0 if settings.DEBUG else 0.2,
         # Filter out noisy health check transactions
         traces_sampler=lambda ctx: (
             0.0 if ctx.get("transaction_context", {}).get("name", "").startswith("GET /health") else None
diff --git a/frontend/src/components/common/ErrorBoundary.tsx b/frontend/src/components/common/ErrorBoundary.tsx
index e2f4a371..7d9b327d 100644
--- a/frontend/src/components/common/ErrorBoundary.tsx
+++ b/frontend/src/components/common/ErrorBoundary.tsx
@@ -1,60 +1,55 @@
-import { Component, type ReactNode } from 'react'
+import * as Sentry from '@sentry/react'
+import { type ReactNode } from 'react'
 import { Button } from '@/components/ui/Button'
 
+interface FallbackProps {
+  error: Error
+  resetError: () => void
+}
+
+function DefaultFallback({ error, resetError }: FallbackProps) {
+  return (
+    <div className="flex min-h-[400px] flex-col items-center justify-center p-8">
+      <div className="max-w-md text-center">
+        <h2 className="mb-2 text-xl font-semibold text-red-400">
+          Something went wrong
+        </h2>
+        <p className="mb-4 text-muted-foreground">
+          An unexpected error occurred. Please try refreshing the page.
+        </p>
+        <pre className="mb-4 overflow-auto rounded-xl bg-white/5 border border-border p-3 text-left text-xs text-red-400">
+          {error.message}
+        </pre>
+        <div className="flex justify-center gap-3">
+          <Button variant="secondary" onClick={resetError}>
+            Try Again
+          </Button>
+          <Button onClick={() => window.location.reload()}>
+            Refresh Page
+          </Button>
+        </div>
+      </div>
+    </div>
+  )
+}
+
 interface Props {
   children: ReactNode
   fallback?: ReactNode
 }
 
-interface State {
-  hasError: boolean
-  error: Error | null
-}
-
-export class ErrorBoundary extends Component<Props, State> {
-  constructor(props: Props) {
-    super(props)
-    this.state = { hasError: false, error: null }
-  }
-
-  static getDerivedStateFromError(error: Error): State {
-    return { hasError: true, error }
-  }
-
-  componentDidCatch(error: Error, errorInfo: React.ErrorInfo) {
-    console.error('ErrorBoundary caught an error:', error, errorInfo)
-  }
-
-  render() {
-    if (this.state.hasError) {
-      if (this.props.fallback) {
-        return this.props.fallback
-      }
-
-      return (
-        <div className="flex min-h-[400px] flex-col items-center justify-center p-8">
-          <div className="max-w-md text-center">
-            <h2 className="mb-2 text-xl font-semibold text-red-400">
-              Something went wrong
-            </h2>
-            <p className="mb-4 text-muted-foreground">
-              An unexpected error occurred. Please try refreshing the page.
-            </p>
-            {this.state.error && (
-              <pre className="mb-4 overflow-auto rounded-xl bg-white/5 border border-border p-3 text-left text-xs text-red-400">
-                {this.state.error.message}
-              </pre>
-            )}
-            <Button onClick={() => window.location.reload()}>
-              Refresh Page
-            </Button>
-          </div>
-        </div>
-      )
-    }
-
-    return this.props.children
-  }
+export function ErrorBoundary({ children, fallback }: Props) {
+  return (
+    <Sentry.ErrorBoundary
+      fallback={({ error, resetError }) => {
+        if (fallback) return fallback as React.ReactElement
+        return <DefaultFallback error={error as Error} resetError={resetError} />
+      }}
+      showDialog
+    >
+      {children}
+    </Sentry.ErrorBoundary>
+  )
 }
 
 export default ErrorBoundary
diff --git a/frontend/src/components/common/RouteError.tsx b/frontend/src/components/common/RouteError.tsx
index 01931aea..45ba1d71 100644
--- a/frontend/src/components/common/RouteError.tsx
+++ b/frontend/src/components/common/RouteError.tsx
@@ -1,5 +1,6 @@
 import { useEffect } from 'react'
 import { useRouteError, isRouteErrorResponse, useNavigate } from 'react-router-dom'
+import * as Sentry from '@sentry/react'
 import { Button } from '@/components/ui/Button'
 
 function isChunkLoadError(error: unknown): boolean {
@@ -19,6 +20,13 @@ export function RouteError() {
   const error = useRouteError()
   const navigate = useNavigate()
 
+  // Report route errors to Sentry (skip chunk load errors — those are deploy artifacts)
+  useEffect(() => {
+    if (error && !isChunkLoadError(error)) {
+      Sentry.captureException(error)
+    }
+  }, [error])
+
   // Auto-reload once on chunk load failures (stale deploy)
   useEffect(() => {
     if (isChunkLoadError(error)) {
diff --git a/frontend/src/instrument.ts b/frontend/src/instrument.ts
index 0e484d23..7fed0cc9 100644
--- a/frontend/src/instrument.ts
+++ b/frontend/src/instrument.ts
@@ -10,6 +10,11 @@ Sentry.init({
       maskAllText: false,
       blockAllMedia: false,
     }),
+    // Crash feedback dialog — prompts users after unhandled errors
+    Sentry.feedbackIntegration({
+      autoInject: false,
+      colorScheme: "dark",
+    }),
   ],
 
   // Tracing — capture 100% in dev, 20% in production
@@ -19,7 +24,13 @@ Sentry.init({
     /^https:\/\/api\.resolutionflow\.com/,
   ],
 
-  // Session Replay — record 10% of sessions, 100% of error sessions
-  replaysSessionSampleRate: 0.1,
+  // Session Replay — conserve free-plan quota
+  // 1% of normal sessions, 100% of error sessions
+  replaysSessionSampleRate: import.meta.env.PROD ? 0.01 : 0.0,
   replaysOnErrorSampleRate: 1.0,
 });
+
+// TODO: Remove after verifying Sentry is receiving frontend events
+if (import.meta.env.PROD) {
+  Sentry.captureMessage("ResolutionFlow frontend Sentry verification", "info");
+}
diff --git a/frontend/src/store/authStore.ts b/frontend/src/store/authStore.ts
index a883f6d8..8ada3ccc 100644
--- a/frontend/src/store/authStore.ts
+++ b/frontend/src/store/authStore.ts
@@ -1,5 +1,6 @@
 import { create } from 'zustand'
 import { persist } from 'zustand/middleware'
+import * as Sentry from '@sentry/react'
 import type { User, Token, UserCreate, UserLogin, Account, SubscriptionDetails } from '@/types'
 import { authApi } from '@/api/auth'
 import { apiClient } from '@/api/client'
@@ -81,6 +82,7 @@ export const useAuthStore = create<AuthState>()(
           localStorage.removeItem('access_token')
           localStorage.removeItem('refresh_token')
           clearCachedQuota()
+          Sentry.setUser(null)
           set({ user: null, token: null, account: null, subscription: null, isAuthenticated: false, error: null })
         }
       },
@@ -104,6 +106,9 @@ export const useAuthStore = create<AuthState>()(
             throw reason
           }
 
+          // Set Sentry user context for error attribution
+          Sentry.setUser({ id: user.id, email: user.email })
+
           set({ user, account, subscription, isLoading: false })
         } catch (error: unknown) {
           const message = error instanceof Error ? error.message : 'Failed to fetch user'