diff --git a/desktop/src/components/browser/BrowserSurface.test.tsx b/desktop/src/components/browser/BrowserSurface.test.tsx
new file mode 100644
index 00000000..6e44289f
--- /dev/null
+++ b/desktop/src/components/browser/BrowserSurface.test.tsx
@@ -0,0 +1,45 @@
+import '@testing-library/jest-dom'
+import { fireEvent, render, screen } from '@testing-library/react'
+import { afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
+
+beforeAll(() => {
+  globalThis.ResizeObserver = class { observe() {} unobserve() {} disconnect() {} } as unknown as typeof ResizeObserver
+})
+
+const { bridge } = vi.hoisted(() => ({
+  bridge: { open: vi.fn(), navigate: vi.fn(), setBounds: vi.fn(), setVisible: vi.fn(), close: vi.fn() },
+}))
+vi.mock('../../lib/previewBridge', () => ({ previewBridge: bridge }))
+
+import { BrowserSurface } from './BrowserSurface'
+import { useBrowserPanelStore } from '../../stores/browserPanelStore'
+
+afterEach(() => {
+  Object.values(bridge).forEach((f) => f.mockReset())
+  useBrowserPanelStore.setState(useBrowserPanelStore.getInitialState(), true)
+})
+
+describe('BrowserSurface', () => {
+  it('opens the preview at the session url on mount when surface is open', () => {
+    useBrowserPanelStore.getState().open('s1', 'http://localhost:5173/')
+    render(<BrowserSurface sessionId="s1" />)
+    expect(bridge.open).toHaveBeenCalledWith('http://localhost:5173/', expect.objectContaining({ width: expect.any(Number) }))
+  })
+
+  it('navigating via address bar calls store + bridge', () => {
+    useBrowserPanelStore.getState().open('s1', 'http://localhost:5173/')
+    render(<BrowserSurface sessionId="s1" />)
+    const input = screen.getByRole('textbox')
+    fireEvent.change(input, { target: { value: 'http://localhost:3000/' } })
+    fireEvent.submit(input.closest('form')!)
+    expect(bridge.navigate).toHaveBeenCalledWith('http://localhost:3000/')
+    expect(useBrowserPanelStore.getState().bySession['s1']!.url).toBe('http://localhost:3000/')
+  })
+
+  it('hides the native webview on unmount', () => {
+    useBrowserPanelStore.getState().open('s1', 'http://localhost:5173/')
+    const { unmount } = render(<BrowserSurface sessionId="s1" />)
+    unmount()
+    expect(bridge.setVisible).toHaveBeenLastCalledWith(false)
+  })
+})
diff --git a/desktop/src/components/browser/BrowserSurface.tsx b/desktop/src/components/browser/BrowserSurface.tsx
new file mode 100644
index 00000000..f51d39aa
--- /dev/null
+++ b/desktop/src/components/browser/BrowserSurface.tsx
@@ -0,0 +1,54 @@
+import { useEffect, useLayoutEffect, useRef } from 'react'
+import { BrowserAddressBar } from './BrowserAddressBar'
+import { computeWebviewBounds } from './computeWebviewBounds'
+import { previewBridge } from '../../lib/previewBridge'
+import { useBrowserPanelStore } from '../../stores/browserPanelStore'
+
+export function BrowserSurface({ sessionId }: { sessionId: string }) {
+  const hostRef = useRef<HTMLDivElement>(null)
+  const session = useBrowserPanelStore((s) => s.bySession[sessionId])
+  const store = useBrowserPanelStore.getState()
+
+  const reportBounds = () => {
+    const el = hostRef.current
+    if (!el) return
+    previewBridge.setBounds(computeWebviewBounds(el.getBoundingClientRect()))
+  }
+
+  useLayoutEffect(() => {
+    const el = hostRef.current
+    if (!el || !session) return
+    previewBridge.open(session.url, computeWebviewBounds(el.getBoundingClientRect()))
+    previewBridge.setVisible(true)
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [sessionId])
+
+  useEffect(() => {
+    const el = hostRef.current
+    if (!el) return
+    const ro = new ResizeObserver(() => reportBounds())
+    ro.observe(el)
+    window.addEventListener('resize', reportBounds)
+    return () => { ro.disconnect(); window.removeEventListener('resize', reportBounds) }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [sessionId])
+
+  useEffect(() => () => { previewBridge.setVisible(false) }, [])
+
+  if (!session) return null
+
+  return (
+    <div className="flex h-full flex-col">
+      <BrowserAddressBar
+        url={session.url}
+        canGoBack={session.canGoBack}
+        canGoForward={session.canGoForward}
+        onNavigate={(url) => { store.navigate(sessionId, url); previewBridge.navigate(url) }}
+        onBack={() => { store.goBack(sessionId); previewBridge.navigate(useBrowserPanelStore.getState().bySession[sessionId]!.url) }}
+        onForward={() => { store.goForward(sessionId); previewBridge.navigate(useBrowserPanelStore.getState().bySession[sessionId]!.url) }}
+        onReload={() => previewBridge.navigate(session.url)}
+      />
+      <div ref={hostRef} className="flex-1" data-testid="preview-host" />
+    </div>
+  )
+}