diff --git a/src/__tests__/realtime.test.ts b/src/__tests__/realtime.test.ts
new file mode 100644
index 0000000..99987d9
--- /dev/null
+++ b/src/__tests__/realtime.test.ts
@@ -0,0 +1,105 @@
+import { describe, test, expect, vi, beforeEach } from "vitest"
+
+// Mock next/navigation
+const mockRefresh = vi.fn()
+vi.mock("next/navigation", () => ({
+  useRouter: () => ({
+    refresh: mockRefresh,
+  }),
+}))
+
+// Mock Supabase browser client
+const mockOn = vi.fn()
+const mockSubscribe = vi.fn()
+const mockRemoveChannel = vi.fn()
+const mockChannel = {
+  on: mockOn,
+  subscribe: mockSubscribe,
+}
+// Make .on() chainable
+mockOn.mockReturnValue(mockChannel)
+
+vi.mock("@/lib/supabase/client", () => ({
+  createClient: () => ({
+    channel: () => mockChannel,
+    removeChannel: mockRemoveChannel,
+  }),
+}))
+
+// Mock react
+const cleanupFns: (() => void)[] = []
+vi.mock("react", async () => {
+  const actual = await vi.importActual("react")
+  return {
+    ...actual,
+    useEffect: (fn: () => (() => void) | void) => {
+      const cleanup = fn()
+      if (cleanup) cleanupFns.push(cleanup)
+    },
+    useMemo: (fn: () => unknown) => fn(),
+  }
+})
+
+import { useRealtimeSubscription } from "@/hooks/useRealtimeSubscription"
+
+describe("useRealtimeSubscription", () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    cleanupFns.length = 0
+    mockOn.mockReturnValue(mockChannel)
+  })
+
+  test("subscribes to specified tables", () => {
+    useRealtimeSubscription([
+      { table: "checks" },
+      { table: "incidents" },
+    ])
+
+    expect(mockOn).toHaveBeenCalledTimes(2)
+    expect(mockOn).toHaveBeenCalledWith(
+      "postgres_changes",
+      expect.objectContaining({ table: "checks", event: "*", schema: "public" }),
+      expect.any(Function)
+    )
+    expect(mockOn).toHaveBeenCalledWith(
+      "postgres_changes",
+      expect.objectContaining({ table: "incidents", event: "*", schema: "public" }),
+      expect.any(Function)
+    )
+    expect(mockSubscribe).toHaveBeenCalledTimes(1)
+  })
+
+  test("subscribes with filter when provided", () => {
+    useRealtimeSubscription([
+      { table: "checks", filter: "site_id=eq.site-1" },
+    ])
+
+    expect(mockOn).toHaveBeenCalledWith(
+      "postgres_changes",
+      expect.objectContaining({
+        table: "checks",
+        filter: "site_id=eq.site-1",
+      }),
+      expect.any(Function)
+    )
+  })
+
+  test("calls router.refresh on change", () => {
+    useRealtimeSubscription([{ table: "checks" }])
+
+    // Get the callback passed to .on()
+    const callback = mockOn.mock.calls[0][2]
+    callback()
+
+    expect(mockRefresh).toHaveBeenCalledTimes(1)
+  })
+
+  test("removes channel on cleanup", () => {
+    useRealtimeSubscription([{ table: "checks" }])
+
+    expect(cleanupFns).toHaveLength(1)
+    cleanupFns[0]()
+
+    expect(mockRemoveChannel).toHaveBeenCalledWith(mockChannel)
+  })
+})
diff --git a/src/app/page.tsx b/src/app/page.tsx
index e6b3aa0..ae293ba 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -4,6 +4,7 @@ import type { Site, Check, Incident } from "@/lib/supabase/types"
 import { formatTimeAgo, formatDuration } from "@/lib/format"
 import AddSiteCard from "@/components/AddSiteCard"
 import EditSiteButton from "@/components/EditSiteButton"
+import RealtimeStatusPage from "@/components/RealtimeStatusPage"
 
 export const revalidate = 0
 
@@ -58,6 +59,7 @@ export default async function StatusPage() {
       className="max-w-[960px] mx-auto"
       style={{ padding: "36px 24px 80px" }}
     >
+      <RealtimeStatusPage />
       {incidents.length > 0 && (
         <section>
           <h2
diff --git a/src/components/RealtimeIncidentDetail.tsx b/src/components/RealtimeIncidentDetail.tsx
new file mode 100644
index 0000000..c1c3ef6
--- /dev/null
+++ b/src/components/RealtimeIncidentDetail.tsx
@@ -0,0 +1,22 @@
+"use client"
+
+import { useMemo } from "react"
+import { useRealtimeSubscription } from "@/hooks/useRealtimeSubscription"
+
+export default function RealtimeIncidentDetail({
+  siteId,
+  incidentId,
+}: {
+  siteId: string
+  incidentId: string
+}) {
+  const subscriptions = useMemo(
+    () => [
+      { table: "checks", filter: `site_id=eq.${siteId}` },
+      { table: "incidents", filter: `id=eq.${incidentId}` },
+    ],
+    [siteId, incidentId]
+  )
+  useRealtimeSubscription(subscriptions)
+  return null
+}
diff --git a/src/components/RealtimeSiteDetail.tsx b/src/components/RealtimeSiteDetail.tsx
new file mode 100644
index 0000000..e9f805b
--- /dev/null
+++ b/src/components/RealtimeSiteDetail.tsx
@@ -0,0 +1,16 @@
+"use client"
+
+import { useMemo } from "react"
+import { useRealtimeSubscription } from "@/hooks/useRealtimeSubscription"
+
+export default function RealtimeSiteDetail({ siteId }: { siteId: string }) {
+  const subscriptions = useMemo(
+    () => [
+      { table: "checks", filter: `site_id=eq.${siteId}` },
+      { table: "incidents", filter: `site_id=eq.${siteId}` },
+    ],
+    [siteId]
+  )
+  useRealtimeSubscription(subscriptions)
+  return null
+}
diff --git a/src/components/RealtimeStatusPage.tsx b/src/components/RealtimeStatusPage.tsx
new file mode 100644
index 0000000..b3fa42b
--- /dev/null
+++ b/src/components/RealtimeStatusPage.tsx
@@ -0,0 +1,17 @@
+"use client"
+
+import { useMemo } from "react"
+import { useRealtimeSubscription } from "@/hooks/useRealtimeSubscription"
+
+export default function RealtimeStatusPage() {
+  const subscriptions = useMemo(
+    () => [
+      { table: "checks" },
+      { table: "incidents" },
+      { table: "sites" },
+    ],
+    []
+  )
+  useRealtimeSubscription(subscriptions)
+  return null
+}
diff --git a/src/hooks/useRealtimeSubscription.ts b/src/hooks/useRealtimeSubscription.ts
new file mode 100644
index 0000000..83880d7
--- /dev/null
+++ b/src/hooks/useRealtimeSubscription.ts
@@ -0,0 +1,41 @@
+"use client"
+
+import { useEffect } from "react"
+import { useRouter } from "next/navigation"
+import { createClient } from "@/lib/supabase/client"
+
+type SubscriptionConfig = {
+  table: string
+  filter?: string
+}
+
+export function useRealtimeSubscription(subscriptions: SubscriptionConfig[]) {
+  const router = useRouter()
+
+  useEffect(() => {
+    const supabase = createClient()
+
+    const channel = supabase
+      .channel("realtime-updates")
+
+    for (const sub of subscriptions) {
+      const config: Record<string, string> = {
+        event: "*",
+        schema: "public",
+        table: sub.table,
+      }
+      if (sub.filter) {
+        config.filter = sub.filter
+      }
+      channel.on("postgres_changes" as never, config, () => {
+        router.refresh()
+      })
+    }
+
+    channel.subscribe()
+
+    return () => {
+      supabase.removeChannel(channel)
+    }
+  }, [router, subscriptions])
+}