diff --git a/nanobot/channels/matrix.py b/nanobot/channels/matrix.py
index 794cc51..f85aab5 100644
--- a/nanobot/channels/matrix.py
+++ b/nanobot/channels/matrix.py
@@ -43,7 +43,7 @@ TYPING_NOTICE_TIMEOUT_MS = 30_000
 # https://spec.matrix.org/v1.17/client-server-api/#typing-notifications
 # Keepalive interval must stay below TYPING_NOTICE_TIMEOUT_MS so the typing
 # indicator does not expire while the agent is still processing.
-TYPING_KEEPALIVE_INTERVAL_SECONDS = 20.0
+TYPING_KEEPALIVE_INTERVAL_MS = 20_000
 MATRIX_HTML_FORMAT = "org.matrix.custom.html"
 MATRIX_ATTACHMENT_MARKER_TEMPLATE = "[attachment: {}]"
 MATRIX_ATTACHMENT_TOO_LARGE_TEMPLATE = "[attachment: {} - too large]"
@@ -715,7 +715,7 @@ class MatrixChannel(BaseChannel):
         async def _typing_loop() -> None:
             try:
                 while self._running:
-                    await asyncio.sleep(TYPING_KEEPALIVE_INTERVAL_SECONDS)
+                    await asyncio.sleep(TYPING_KEEPALIVE_INTERVAL_MS / 1000)
                     await self._set_typing(room_id, True)
             except asyncio.CancelledError:
                 pass
diff --git a/tests/test_matrix_channel.py b/tests/test_matrix_channel.py
index f475aac..c6714c2 100644
--- a/tests/test_matrix_channel.py
+++ b/tests/test_matrix_channel.py
@@ -332,7 +332,7 @@ async def test_typing_keepalive_refreshes_periodically(monkeypatch) -> None:
     channel.client = client
     channel._running = True
 
-    monkeypatch.setattr(matrix_module, "TYPING_KEEPALIVE_INTERVAL_SECONDS", 0.01)
+    monkeypatch.setattr(matrix_module, "TYPING_KEEPALIVE_INTERVAL_MS", 10)
 
     await channel._start_typing_keepalive("!room:matrix.org")
     await asyncio.sleep(0.03)