diff --git a/src/app/features/room/RoomOutbox.actions.test.tsx b/src/app/features/room/RoomOutbox.actions.test.tsx
new file mode 100644
index 00000000..0dbd4f5d
--- /dev/null
+++ b/src/app/features/room/RoomOutbox.actions.test.tsx
@@ -0,0 +1,102 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { enqueueOutbox, failOutbox, loadOutbox } from '../../state/room/composerStore';
+import { RoomOutbox } from './RoomOutbox';
+
+// The component's hooks are held still (state is its initial value, effects do not run) so the element tree
+// it returns can be read and its click handlers called without a DOM.
+vi.mock('react', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('react')>();
+  const useState = (init: unknown) => [
+    typeof init === 'function' ? (init as () => unknown)() : init,
+    () => undefined,
+  ];
+  return {
+    ...actual,
+    default: { ...actual, useState, useEffect: () => undefined },
+    useState,
+    useEffect: () => undefined,
+  };
+});
+
+type El = { props?: { children?: unknown; onClick?: () => void } };
+const flatten = (node: unknown): El[] => {
+  if (Array.isArray(node)) return node.flatMap(flatten);
+  if (node && typeof node === 'object') {
+    const el = node as El;
+    return [el, ...flatten(el.props?.children)];
+  }
+  return [];
+};
+const textOf = (node: unknown): string => {
+  if (typeof node === 'string' || typeof node === 'number') return String(node);
+  if (Array.isArray(node)) return node.map(textOf).join('');
+  if (node && typeof node === 'object') return textOf((node as El).props?.children);
+  return '';
+};
+/** The onClick of the chip whose label is `label`. */
+const clickOf = (tree: unknown, label: string) => {
+  const chip = flatten(tree).find((e) => e.props?.onClick && textOf(e) === label);
+  if (!chip?.props?.onClick) throw new Error(`no ${label} chip`);
+  return chip.props.onClick;
+};
+
+describe('RoomOutbox actions', () => {
+  beforeEach(() => {
+    const m = new Map<string, string>();
+    vi.stubGlobal('localStorage', {
+      getItem: (k: string) => m.get(k) ?? null,
+      setItem: (k: string, v: string) => {
+        m.set(k, v);
+      },
+      removeItem: (k: string) => {
+        m.delete(k);
+      },
+    });
+    enqueueOutbox('@a:x', { txnId: 'keep', roomId: '!r:x', content: { body: 'stay' } });
+    enqueueOutbox('@a:x', { txnId: 'bad', roomId: '!r:x', content: { body: 'did not go' } });
+    failOutbox('@a:x', 'bad', 'ECONNRESET');
+  });
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  const mount = () => {
+    const mx = {
+      getUserId: () => '@a:x',
+      makeTxnId: () => 'txn-new',
+      getRoom: () => undefined,
+      sendEvent: vi.fn().mockResolvedValue({ event_id: '$e' }),
+    };
+    const tree = (RoomOutbox as unknown as (p: unknown) => unknown)({ mx, roomId: '!r:x' });
+    return { mx, tree };
+  };
+
+  it('Discard removes that message from the outbox and no other', () => {
+    const { mx, tree } = mount();
+    // both entries are shown; the failed one is the one with Discard
+    clickOf(tree, 'Discard')();
+    expect(loadOutbox('@a:x').map((e) => e.txnId)).toEqual(['keep']);
+    expect(mx.sendEvent).not.toHaveBeenCalled();
+  });
+
+  it('Resend sends that message again and does not discard it first', async () => {
+    const { mx, tree } = mount();
+    // the server has not answered yet: the resend is in flight
+    mx.sendEvent.mockReturnValue(
+      new Promise<never>(() => {
+        // never settles
+      })
+    );
+    clickOf(tree, 'Resend')();
+    await Promise.resolve();
+    expect(mx.sendEvent).toHaveBeenCalledTimes(1);
+    expect(mx.sendEvent).toHaveBeenCalledWith(
+      '!r:x',
+      'm.room.message',
+      { body: 'did not go' },
+      'bad'
+    );
+    // still in the outbox, pending again under the same id, until the server confirms it
+    expect(loadOutbox('@a:x').find((e) => e.txnId === 'bad')).toMatchObject({ status: 'pending' });
+  });
+});
diff --git a/src/app/features/room/RoomOutbox.render.test.tsx b/src/app/features/room/RoomOutbox.render.test.tsx
new file mode 100644
index 00000000..e4c258df
--- /dev/null
+++ b/src/app/features/room/RoomOutbox.render.test.tsx
@@ -0,0 +1,64 @@
+import React from 'react';
+import { renderToStaticMarkup } from 'react-dom/server';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { enqueueOutbox, failOutbox } from '../../state/room/composerStore';
+import { RoomOutbox } from './RoomOutbox';
+
+// What the person sees under the timeline for sends the server has not confirmed.
+const text = (html: string) => html.replace(/<[^>]*>/g, ' ').replace(/\s+/g, ' ');
+
+describe('RoomOutbox as rendered', () => {
+  beforeEach(() => {
+    const m = new Map<string, string>();
+    vi.stubGlobal('localStorage', {
+      getItem: (k: string) => m.get(k) ?? null,
+      setItem: (k: string, v: string) => {
+        m.set(k, v);
+      },
+      removeItem: (k: string) => {
+        m.delete(k);
+      },
+    });
+  });
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  const mx = { getUserId: () => '@a:x' } as never;
+  const entry = (txnId: string, roomId: string, body: string) => ({
+    txnId,
+    roomId,
+    content: { body },
+  });
+
+  it('renders nothing when the room has no unconfirmed sends', () => {
+    enqueueOutbox('@a:x', entry('t1', '!other:x', 'elsewhere'));
+    expect(renderToStaticMarkup(<RoomOutbox mx={mx} roomId="!r:x" />)).toBe('');
+  });
+
+  it('shows a fresh send as Sending with its text and no Resend', () => {
+    enqueueOutbox('@a:x', entry('t1', '!r:x', 'on its way'), Date.now() + 1000);
+    const html = renderToStaticMarkup(<RoomOutbox mx={mx} roomId="!r:x" />);
+    expect(html).toContain('data-outbox-status="pending"');
+    expect(text(html)).toContain('Sending…');
+    expect(text(html)).toContain('on its way');
+    expect(text(html)).not.toContain('Resend');
+  });
+
+  it('shows a failed send with its error, Resend and Discard', () => {
+    enqueueOutbox('@a:x', entry('t2', '!r:x', 'did not go'));
+    failOutbox('@a:x', 't2', 'ECONNRESET');
+    const html = renderToStaticMarkup(<RoomOutbox mx={mx} roomId="!r:x" />);
+    expect(html).toContain('data-outbox-status="failed"');
+    expect(text(html)).toContain('Not sent: ECONNRESET');
+    expect(text(html)).toContain('Resend');
+    expect(text(html)).toContain('Discard');
+  });
+
+  it('shows a send left over from before this page load as interrupted, resendable', () => {
+    enqueueOutbox('@a:x', entry('t3', '!r:x', 'lost to a reload'), 5);
+    const html = renderToStaticMarkup(<RoomOutbox mx={mx} roomId="!r:x" />);
+    expect(text(html)).toContain('Interrupted by a reload');
+    expect(text(html)).toContain('Resend');
+  });
+});
diff --git a/src/app/features/room/RoomOutbox.test.ts b/src/app/features/room/RoomOutbox.test.ts
index 55597694..30d7c0bb 100644
--- a/src/app/features/room/RoomOutbox.test.ts
+++ b/src/app/features/room/RoomOutbox.test.ts
@@ -17,6 +17,11 @@ describe('outboxView', () => {
     });
   });
 
+  it('offers Resend to a pending send at 30 s and not a millisecond before', () => {
+    const at = (ms: number) => outboxView({ status: 'pending', ts: 100 }, 100 + ms, 0).canResend;
+    expect([at(29_999), at(30_000)]).toEqual([false, true]);
+  });
+
   it('an entry older than this page load reads as interrupted', () => {
     expect(outboxView({ status: 'pending', ts: 5 }, 6, 10).label).toMatch(/Interrupted/);
   });
diff --git a/src/client/stallRecovery.test.ts b/src/client/stallRecovery.test.ts
new file mode 100644
index 00000000..ae1e5217
--- /dev/null
+++ b/src/client/stallRecovery.test.ts
@@ -0,0 +1,148 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { PAGE_ID, loadOutbox } from '../app/state/room/composerStore';
+import { resendInterrupted, sendTracked } from '../app/state/room/outboxSend';
+import { RECOVER_RELOAD_MIN_GAP_MS, ownPendingAges, reloadToRecoverSync } from './initMatrix';
+import { SEND_STALL_MS, WATCHDOG_INTERVAL_MS, startWatchdog } from './watchdog';
+
+// The dead-connection story from the user's side: a send hangs, the page notices and reloads
+// itself once, and the message goes out again from the outbox under its own txn id.
+const memoryStore = (m = new Map<string, string>()) => ({
+  getItem: (k: string) => m.get(k) ?? null,
+  setItem: (k: string, v: string) => {
+    m.set(k, v);
+  },
+  removeItem: (k: string) => {
+    m.delete(k);
+  },
+});
+
+const OUTBOX_KEY = 'ratatoskr.outbox.@a:x';
+
+describe('a send that hangs on a dead connection', () => {
+  let storage: Map<string, string>;
+  beforeEach(() => {
+    vi.useFakeTimers();
+    storage = new Map();
+    vi.stubGlobal('localStorage', memoryStore(storage));
+  });
+  afterEach(() => {
+    vi.useRealTimers();
+    vi.unstubAllGlobals();
+  });
+
+  // Every send gets its own txn id, as the SDK's makeTxnId gives; a client that hands out one
+  // constant id could not tell a resend of the right message from a resend of the wrong one.
+  const hungClient = () => {
+    let n = 0;
+    return {
+      getUserId: () => '@a:x',
+      makeTxnId: () => {
+        n += 1;
+        return `txn-${n}`;
+      },
+      sendEvent: vi.fn(
+        () =>
+          new Promise<never>(() => {
+            // never settles: the request is hung
+          })
+      ),
+      getRoom: () => undefined,
+    };
+  };
+  const watch = (env: { visible: boolean; online: boolean }) => {
+    const reload = vi.fn();
+    const session = memoryStore();
+    const stop = startWatchdog({
+      pendingAges: () => ownPendingAges('@a:x'),
+      isVisible: () => env.visible,
+      isOnline: () => env.online,
+      recover: () => reloadToRecoverSync(Date.now(), () => session, reload),
+    });
+    return { reload, stop };
+  };
+  const stalled = () => vi.advanceTimersByTime(SEND_STALL_MS + 2 * WATCHDOG_INTERVAL_MS);
+
+  it('is kept in the outbox, reloads the page once after the stall, and each message is resent under its own txn id', async () => {
+    const mx = hungClient();
+    const first = { msgtype: 'm.text', body: 'hello from a dead connection' };
+    const second = { msgtype: 'm.text', body: 'and a second one' };
+    const { reload, stop } = watch({ visible: true, online: true });
+
+    sendTracked(mx as never, '!r:x', first);
+    sendTracked(mx as never, '!q:x', second);
+    expect(loadOutbox('@a:x')).toMatchObject([
+      { txnId: 'txn-1', status: 'pending' },
+      { txnId: 'txn-2', status: 'pending' },
+    ]);
+
+    vi.advanceTimersByTime(SEND_STALL_MS - WATCHDOG_INTERVAL_MS);
+    expect(reload).not.toHaveBeenCalled();
+    vi.advanceTimersByTime(2 * WATCHDOG_INTERVAL_MS);
+    expect(reload).toHaveBeenCalledTimes(1);
+    // the stall persists across the reload guard window: no reload loop
+    vi.advanceTimersByTime(RECOVER_RELOAD_MIN_GAP_MS - 2 * WATCHDOG_INTERVAL_MS);
+    expect(reload).toHaveBeenCalledTimes(1);
+    stop();
+
+    // the reloaded page: the entries are older than the page, the network works again
+    const send = vi.fn().mockResolvedValue({ event_id: '$e' });
+    const reloaded = { ...mx, sendEvent: send };
+    await resendInterrupted(reloaded as never, Date.now() + 1);
+    expect(send).toHaveBeenCalledTimes(2);
+    expect(send).toHaveBeenCalledWith('!r:x', 'm.room.message', first, 'txn-1');
+    expect(send).toHaveBeenCalledWith('!q:x', 'm.room.message', second, 'txn-2');
+    expect(loadOutbox('@a:x')).toEqual([]);
+  });
+
+  it('resends under a fresh txn id when the SDK still holds an echo for the old one', async () => {
+    const mx = hungClient();
+    const content = { msgtype: 'm.text', body: 'echo still held' };
+    sendTracked(mx as never, '!r:x', content);
+    expect(loadOutbox('@a:x')).toMatchObject([{ txnId: 'txn-1' }]);
+
+    const send = vi.fn().mockResolvedValue({ event_id: '$e' });
+    const held = {
+      ...mx,
+      makeTxnId: () => 'txn-fresh',
+      sendEvent: send,
+      getRoom: () => ({ getEventForTxnId: (id: string) => (id === 'txn-1' ? {} : undefined) }),
+    };
+    await resendInterrupted(held as never, Date.now() + 1);
+    expect(send).toHaveBeenCalledTimes(1);
+    expect(send).toHaveBeenCalledWith('!r:x', 'm.room.message', content, 'txn-fresh');
+    expect(loadOutbox('@a:x')).toEqual([]);
+  });
+
+  it.each([
+    ['hidden', { visible: false, online: true }],
+    ['offline', { visible: true, online: false }],
+  ])('does not reload a stalled page while it is %s, and does once it is back', (_name, env) => {
+    const mx = hungClient();
+    const state = { ...env };
+    const { reload, stop } = watch(state);
+    sendTracked(mx as never, '!r:x', { body: 'x' });
+    stalled();
+    vi.advanceTimersByTime(10 * SEND_STALL_MS);
+    expect(reload).not.toHaveBeenCalled();
+    state.visible = true;
+    state.online = true;
+    vi.advanceTimersByTime(2 * WATCHDOG_INTERVAL_MS);
+    expect(reload).toHaveBeenCalledTimes(1);
+    stop();
+  });
+
+  it('does not reload for a send that belongs to another tab, or one that already failed', () => {
+    const mx = hungClient();
+    const { reload, stop } = watch({ visible: true, online: true });
+    sendTracked(mx as never, '!r:x', { body: 'theirs' });
+    sendTracked(mx as never, '!r:x', { body: 'failed' });
+    const entries = JSON.parse(storage.get(OUTBOX_KEY) as string);
+    entries[0].tab = `${PAGE_ID}-other`;
+    entries[1].status = 'failed';
+    storage.set(OUTBOX_KEY, JSON.stringify(entries));
+    stalled();
+    vi.advanceTimersByTime(10 * SEND_STALL_MS);
+    expect(reload).not.toHaveBeenCalled();
+    stop();
+  });
+});
diff --git a/src/client/startClient.test.ts b/src/client/startClient.test.ts
new file mode 100644
index 00000000..11b488e3
--- /dev/null
+++ b/src/client/startClient.test.ts
@@ -0,0 +1,115 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { enqueueOutbox } from '../app/state/room/composerStore';
+import { PAGE_START } from '../app/state/room/outboxSend';
+import { startClient } from './initMatrix';
+import { startResumeSync } from './resumeSync';
+import { startWatchdog } from './watchdog';
+
+vi.mock('./resumeSync', () => ({ startResumeSync: vi.fn() }));
+vi.mock('./watchdog', async (importOriginal) => ({
+  ...(await importOriginal<typeof import('./watchdog')>()),
+  startWatchdog: vi.fn(() => () => undefined),
+}));
+
+const memoryStore = (m = new Map<string, string>()) => ({
+  getItem: (k: string) => m.get(k) ?? null,
+  setItem: (k: string, v: string) => {
+    m.set(k, v);
+  },
+  removeItem: (k: string) => {
+    m.delete(k);
+  },
+});
+
+// startClient is the one place the dead-connection pieces are wired to the page: what the watchdog reads,
+// when it may fire, what it does, and what runs after the reload. These tests call it and exercise that wiring.
+describe('startClient wiring', () => {
+  let handlers: Array<(state: string) => void>;
+  let mx: Record<string, unknown> & {
+    sendEvent: ReturnType<typeof vi.fn>;
+    off: ReturnType<typeof vi.fn>;
+  };
+  beforeEach(() => {
+    vi.clearAllMocks();
+    handlers = [];
+    vi.stubGlobal('localStorage', memoryStore());
+    mx = {
+      startClient: vi.fn().mockResolvedValue(undefined),
+      getUserId: () => '@a:x',
+      makeTxnId: () => 'txn-new',
+      getRoom: () => undefined,
+      sendEvent: vi.fn().mockResolvedValue({ event_id: '$e' }),
+      on: (_ev: string, h: (state: string) => void) => {
+        handlers.push(h);
+      },
+      off: vi.fn(),
+    };
+  });
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  const watchdogOptions = () =>
+    (startWatchdog as unknown as ReturnType<typeof vi.fn>).mock.calls[0][0] as Parameters<
+      typeof startWatchdog
+    >[0];
+
+  it('starts sync, the resume nudge and the watchdog once per client', async () => {
+    await startClient(mx as never);
+    await startClient(mx as never);
+    expect(mx.startClient).toHaveBeenCalledTimes(2);
+    expect(startResumeSync).toHaveBeenCalledTimes(1);
+    expect(startResumeSync).toHaveBeenCalledWith(mx);
+    expect(startWatchdog).toHaveBeenCalledTimes(1);
+  });
+
+  it("feeds the watchdog this page's pending sends for this user", async () => {
+    await startClient(mx as never);
+    const { pendingAges } = watchdogOptions();
+    expect(pendingAges()).toEqual([]);
+    enqueueOutbox('@a:x', { txnId: 't', roomId: '!r:x', content: {} }, Date.now() - 7000);
+    enqueueOutbox('@b:x', { txnId: 'u', roomId: '!r:x', content: {} }, Date.now() - 1000);
+    const ages = pendingAges();
+    expect(ages).toHaveLength(1);
+    expect(ages[0]).toBeGreaterThanOrEqual(7000);
+  });
+
+  it('reads visibility and connectivity from the page', async () => {
+    const doc = { visibilityState: 'visible' };
+    const nav = { onLine: true };
+    vi.stubGlobal('document', doc);
+    vi.stubGlobal('navigator', nav);
+    await startClient(mx as never);
+    const { isVisible, isOnline } = watchdogOptions();
+    expect([isVisible(), isOnline()]).toEqual([true, true]);
+    doc.visibilityState = 'hidden';
+    nav.onLine = false;
+    expect([isVisible(), isOnline()]).toEqual([false, false]);
+  });
+
+  it('recovers by a guarded reload, at most once a minute', async () => {
+    const reload = vi.fn();
+    vi.stubGlobal('window', { location: { reload } });
+    vi.stubGlobal('sessionStorage', memoryStore());
+    await startClient(mx as never);
+    const { recover } = watchdogOptions();
+    recover();
+    recover();
+    expect(reload).toHaveBeenCalledTimes(1);
+  });
+
+  it('resends what a reload interrupted once sync is up, and only once', async () => {
+    enqueueOutbox(
+      '@a:x',
+      { txnId: 'old', roomId: '!r:x', content: { body: 'x' } },
+      PAGE_START - 5000
+    );
+    await startClient(mx as never);
+    expect(handlers).toHaveLength(1);
+    handlers[0]('CONNECTING');
+    expect(mx.sendEvent).not.toHaveBeenCalled();
+    handlers[0]('SYNCING');
+    expect(mx.off).toHaveBeenCalledWith('sync', handlers[0]);
+    expect(mx.sendEvent).toHaveBeenCalledWith('!r:x', 'm.room.message', { body: 'x' }, 'old');
+  });
+});