diff --git a/backend/app/services/sse_manager.py b/backend/app/services/sse_manager.py
index ab15064..9007b1b 100644
--- a/backend/app/services/sse_manager.py
+++ b/backend/app/services/sse_manager.py
@@ -11,7 +11,7 @@ from typing import Optional
 
 import nats
 import structlog
-from nats.js.api import ConsumerConfig, DeliverPolicy, StreamConfig
+from nats.js.api import StreamConfig
 
 from app.config import settings
 
@@ -133,17 +133,12 @@ class SSEConnectionManager:
             last_event_id=last_event_id,
         )
 
-        # Build consumer config for replay support
-        if last_event_id is not None:
-            try:
-                start_seq = int(last_event_id) + 1
-                consumer_cfg = ConsumerConfig(
-                    deliver_policy=DeliverPolicy.BY_START_SEQUENCE, opt_start_seq=start_seq
-                )
-            except (ValueError, TypeError):
-                consumer_cfg = ConsumerConfig(deliver_policy=DeliverPolicy.NEW)
-        else:
-            consumer_cfg = ConsumerConfig(deliver_policy=DeliverPolicy.NEW)
+        # Use ordered consumers for SSE — ephemeral, no server-side state,
+        # no ack tracking.  They auto-clean on disconnect so stale consumers
+        # can't accumulate across API restarts or dropped browser connections.
+        #
+        # ordered_consumer=True implies DeliverPolicy.NEW unless last_event_id
+        # was provided (replay from sequence).
 
         # Subscribe to device events (DEVICE_EVENTS stream -- created by Go poller)
         for subject in _DEVICE_EVENT_SUBJECTS:
@@ -151,7 +146,7 @@ class SSEConnectionManager:
                 sub = await js.subscribe(
                     subject,
                     stream="DEVICE_EVENTS",
-                    config=consumer_cfg,
+                    ordered_consumer=True,
                 )
                 self._subscriptions.append(sub)
             except Exception as exc:
@@ -169,7 +164,7 @@ class SSEConnectionManager:
                 sub = await js.subscribe(
                     subject,
                     stream="ALERT_EVENTS",
-                    config=consumer_cfg,
+                    ordered_consumer=True,
                 )
                 self._subscriptions.append(sub)
             except Exception as exc:
@@ -183,7 +178,7 @@ class SSEConnectionManager:
                             )
                         )
                         sub = await js.subscribe(
-                            subject, stream="ALERT_EVENTS", config=consumer_cfg
+                            subject, stream="ALERT_EVENTS", ordered_consumer=True
                         )
                         self._subscriptions.append(sub)
                         logger.info("sse.stream_created_lazily", stream="ALERT_EVENTS")
@@ -208,7 +203,7 @@ class SSEConnectionManager:
                 sub = await js.subscribe(
                     subject,
                     stream="OPERATION_EVENTS",
-                    config=consumer_cfg,
+                    ordered_consumer=True,
                 )
                 self._subscriptions.append(sub)
             except Exception as exc:
@@ -222,7 +217,7 @@ class SSEConnectionManager:
                             )
                         )
                         sub = await js.subscribe(
-                            subject, stream="OPERATION_EVENTS", config=consumer_cfg
+                            subject, stream="OPERATION_EVENTS", ordered_consumer=True
                         )
                         self._subscriptions.append(sub)
                         logger.info("sse.stream_created_lazily", stream="OPERATION_EVENTS")