diff --git a/server/src/ledgrab/api/auth.py b/server/src/ledgrab/api/auth.py
index ec2cc02..3d10745 100644
--- a/server/src/ledgrab/api/auth.py
+++ b/server/src/ledgrab/api/auth.py
@@ -11,14 +11,13 @@ from starlette.websockets import WebSocket, WebSocketDisconnect
 
 from ledgrab.config import get_config
 from ledgrab.utils import get_logger
+from ledgrab.utils.net_classify import is_loopback as _classify_is_loopback
 
 logger = get_logger(__name__)
 
 # Security scheme for Bearer token
 security = HTTPBearer(auto_error=False)
 
-_LOOPBACK_HOSTS = frozenset({"127.0.0.1", "::1", "localhost", "testclient"})
-
 
 def is_auth_enabled() -> bool:
     """Return True when at least one API key is configured."""
@@ -26,15 +25,15 @@ def is_auth_enabled() -> bool:
 
 
 def _is_loopback(host: str | None) -> bool:
-    """Return True when *host* is a loopback address."""
+    """Return True when *host* is a loopback address.
+
+    Delegates to :func:`ledgrab.utils.net_classify.is_loopback` so this
+    auth gate, the SSRF guard in ``safe_source``, and the LAN-default
+    inference in ``url_scheme`` share one classification source.
+    """
     if not host:
         return False
-    # Strip IPv6 brackets and zone IDs
-    h = host.strip().lower()
-    if h.startswith("[") and h.endswith("]"):
-        h = h[1:-1]
-    h = h.split("%", 1)[0]
-    return h in _LOOPBACK_HOSTS
+    return _classify_is_loopback(host)
 
 
 def verify_api_key(
@@ -142,6 +141,23 @@ def require_authenticated(label: str) -> None:
 WS_AUTH_CLOSE_CODE = 4401
 
 
+WS_ORIGIN_CLOSE_CODE = 4403
+"""Close code sent when a WebSocket request fails the Origin allowlist."""
+
+
+def _is_origin_allowed(origin: str | None, allowed: list[str]) -> bool:
+    """Return True when *origin* matches one of the configured CORS origins.
+
+    Non-browser clients (Python scripts, curl) don't send Origin — those are
+    allowed through; the Bearer-token check on the auth handshake is the
+    primary defence in that case. Browsers always set Origin, so this only
+    blocks cross-site WebSocket connection attempts (CSWSH).
+    """
+    if not origin:
+        return True
+    return origin in set(allowed or [])
+
+
 async def accept_and_authenticate_ws(websocket: WebSocket, timeout: float = 3.0) -> str | None:
     """Accept the WebSocket, then perform first-message auth handshake.
 
@@ -152,6 +168,23 @@ async def accept_and_authenticate_ws(websocket: WebSocket, timeout: float = 3.0)
     Returns the caller label on success, ``None`` on failure (connection
     already closed).
     """
+    # Reject cross-site WebSocket attempts before accepting — a browser-based
+    # attacker page cannot forge the Origin header, so an Origin mismatch is
+    # a strong signal even before the token check. Non-browser clients
+    # legitimately omit Origin; those fall through to the auth handshake.
+    config = get_config()
+    origin = websocket.headers.get("origin")
+    if not _is_origin_allowed(origin, config.server.cors_origins):
+        logger.warning(
+            "Rejected WebSocket from origin %r (not in cors_origins)",
+            origin,
+        )
+        try:
+            await websocket.close(code=WS_ORIGIN_CLOSE_CODE)
+        except Exception:
+            pass
+        return None
+
     await websocket.accept()
     label = await verify_ws_auth(websocket, timeout=timeout)
     if label is None:
diff --git a/server/src/ledgrab/api/dependencies.py b/server/src/ledgrab/api/dependencies.py
index 7ace5af..1718632 100644
--- a/server/src/ledgrab/api/dependencies.py
+++ b/server/src/ledgrab/api/dependencies.py
@@ -37,6 +37,7 @@ from ledgrab.storage.game_integration_store import GameIntegrationStore
 from ledgrab.core.game_integration.event_bus import GameEventBus
 from ledgrab.storage.mqtt_source_store import MQTTSourceStore
 from ledgrab.core.mqtt.mqtt_manager import MQTTManager
+from ledgrab.storage.http_endpoint_store import HTTPEndpointStore
 from ledgrab.storage.audio_processing_template_store import AudioProcessingTemplateStore
 from ledgrab.storage.pattern_template_store import PatternTemplateStore
 
@@ -165,6 +166,10 @@ def get_mqtt_manager() -> MQTTManager:
     return _get("mqtt_manager", "MQTT manager")
 
 
+def get_http_endpoint_store() -> HTTPEndpointStore:
+    return _get("http_endpoint_store", "HTTP endpoint store")
+
+
 def get_audio_processing_template_store() -> AudioProcessingTemplateStore:
     return _get("audio_processing_template_store", "Audio processing template store")
 
@@ -237,6 +242,7 @@ def init_dependencies(
     game_event_bus: GameEventBus | None = None,
     mqtt_store: MQTTSourceStore | None = None,
     mqtt_manager: MQTTManager | None = None,
+    http_endpoint_store: HTTPEndpointStore | None = None,
     audio_processing_template_store: AudioProcessingTemplateStore | None = None,
     pattern_template_store: PatternTemplateStore | None = None,
 ):
@@ -272,6 +278,7 @@ def init_dependencies(
             "game_event_bus": game_event_bus,
             "mqtt_store": mqtt_store,
             "mqtt_manager": mqtt_manager,
+            "http_endpoint_store": http_endpoint_store,
             "audio_processing_template_store": audio_processing_template_store,
             "pattern_template_store": pattern_template_store,
         }
diff --git a/server/src/ledgrab/api/routes/assets.py b/server/src/ledgrab/api/routes/assets.py
index 8cf6fed..70ec093 100644
--- a/server/src/ledgrab/api/routes/assets.py
+++ b/server/src/ledgrab/api/routes/assets.py
@@ -15,7 +15,7 @@ from ledgrab.api.schemas.assets import (
 from ledgrab.config import get_config
 from ledgrab.storage.asset_store import AssetStore
 from ledgrab.storage.base_store import EntityNotFoundError
-from ledgrab.utils import get_logger
+from ledgrab.utils import get_logger, read_upload_capped
 
 logger = get_logger(__name__)
 
@@ -93,10 +93,11 @@ async def upload_asset(
     config = get_config()
     max_size = getattr(getattr(config, "assets", None), "max_file_size_mb", 50) * 1024 * 1024
 
-    data = await file.read()
-    if len(data) > max_size:
+    try:
+        data = await read_upload_capped(file, max_size)
+    except ValueError:
         raise HTTPException(
-            status_code=400,
+            status_code=413,
             detail=f"File too large (max {max_size // (1024 * 1024)} MB)",
         )
 
diff --git a/server/src/ledgrab/api/routes/backup.py b/server/src/ledgrab/api/routes/backup.py
index 80639f8..678eefc 100644
--- a/server/src/ledgrab/api/routes/backup.py
+++ b/server/src/ledgrab/api/routes/backup.py
@@ -28,7 +28,7 @@ from ledgrab.config import get_config
 from ledgrab.core.backup.auto_backup import AutoBackupEngine
 from ledgrab.storage.asset_store import AssetStore
 from ledgrab.storage.database import Database, freeze_writes
-from ledgrab.utils import get_logger
+from ledgrab.utils import get_logger, read_upload_capped
 
 logger = get_logger(__name__)
 
@@ -133,9 +133,11 @@ async def restore_config(
     because restore replaces all configuration including secrets).
     """
     require_authenticated(auth)
-    raw = await file.read()
-    if len(raw) > 200 * 1024 * 1024:  # 200 MB limit (ZIP may contain assets)
-        raise HTTPException(status_code=400, detail="Backup file too large (max 200 MB)")
+    _MAX_BACKUP_BYTES = 200 * 1024 * 1024  # 200 MB (ZIP may contain assets)
+    try:
+        raw = await read_upload_capped(file, _MAX_BACKUP_BYTES)
+    except ValueError:
+        raise HTTPException(status_code=413, detail="Backup file too large (max 200 MB)")
 
     if len(raw) < 100:
         raise HTTPException(status_code=400, detail="File too small to be a valid backup")
diff --git a/server/src/ledgrab/api/routes/webhooks.py b/server/src/ledgrab/api/routes/webhooks.py
index bccd717..d12966e 100644
--- a/server/src/ledgrab/api/routes/webhooks.py
+++ b/server/src/ledgrab/api/routes/webhooks.py
@@ -30,6 +30,9 @@ _RATE_WINDOW = 60.0  # seconds
 _rate_hits: dict[str, list[float]] = defaultdict(list)
 
 
+_RATE_HITS_HARD_CAP = 1024
+
+
 def _check_rate_limit(client_ip: str) -> None:
     """Raise 429 if *client_ip* exceeded the webhook rate limit."""
     now = time.time()
@@ -44,11 +47,21 @@ def _check_rate_limit(client_ip: str) -> None:
         )
     _rate_hits[client_ip].append(now)
 
-    # Periodic cleanup: remove IPs with no recent hits to prevent unbounded growth
+    # Periodic cleanup: remove IPs with no recent hits to prevent unbounded growth.
     if len(_rate_hits) > 100:
         stale = [ip for ip, ts in _rate_hits.items() if not ts or ts[-1] < window_start]
         for ip in stale:
             del _rate_hits[ip]
+    # Hard cap as a final defence against an attacker spraying many distinct
+    # X-Forwarded-For values to drive memory growth past the soft cleanup
+    # threshold. Drop the oldest-touched IPs (by their latest timestamp).
+    if len(_rate_hits) > _RATE_HITS_HARD_CAP:
+        ordered = sorted(
+            _rate_hits.items(),
+            key=lambda kv: kv[1][-1] if kv[1] else 0.0,
+        )
+        for ip, _ in ordered[: len(ordered) - _RATE_HITS_HARD_CAP]:
+            _rate_hits.pop(ip, None)
 
 
 class WebhookPayload(BaseModel):
diff --git a/server/src/ledgrab/core/capture/screen_capture.py b/server/src/ledgrab/core/capture/screen_capture.py
index df3788c..6f45181 100644
--- a/server/src/ledgrab/core/capture/screen_capture.py
+++ b/server/src/ledgrab/core/capture/screen_capture.py
@@ -14,6 +14,12 @@ from ledgrab.utils import get_logger, get_monitor_names, get_monitor_refresh_rat
 
 logger = get_logger(__name__)
 
+# Reused random Generator for sampling. The legacy ``np.random.randint``
+# uses the module-level RandomState which is slightly slower per-call and
+# pulls in extra import-time work; a single Generator is faster and avoids
+# global-state surprises.
+_rng = np.random.default_rng()
+
 
 @dataclass
 class DisplayInfo:
@@ -326,7 +332,11 @@ def calculate_dominant_color(pixels: np.ndarray) -> tuple[int, int, int]:
 
     max_samples = 1000
     if n > max_samples:
-        indices = np.random.randint(0, n, max_samples)
+        # ``Generator.integers`` writes into a fresh buffer once per call;
+        # the legacy ``np.random.randint`` did the same plus extra
+        # bookkeeping. Random (not stride) sampling stays robust against
+        # periodic patterns in screen pixels.
+        indices = _rng.integers(0, n, size=max_samples)
         pixels_reshaped = pixels_reshaped[indices]
 
     # Quantize to 32 levels/channel (drop low 3 bits) and pack into uint32:
diff --git a/server/src/ledgrab/core/devices/discovery_watcher.py b/server/src/ledgrab/core/devices/discovery_watcher.py
index 394beca..782242e 100644
--- a/server/src/ledgrab/core/devices/discovery_watcher.py
+++ b/server/src/ledgrab/core/devices/discovery_watcher.py
@@ -85,6 +85,10 @@ class DiscoveryWatcher:
         self._wled_seen: Dict[str, _DiscoveredEntry] = {}
         # device-path -> entry. Only the serial poller mutates this.
         self._serial_seen: Dict[str, _DiscoveredEntry] = {}
+        # Strong references for fire-and-forget resolve tasks — without
+        # these, Python 3.11+ may GC the task mid-resolve and silently lose
+        # discovery events. Tasks remove themselves on completion.
+        self._resolve_tasks: "set[asyncio.Task]" = set()
 
     # --- lifecycle --------------------------------------------------------
 
@@ -155,12 +159,23 @@ class DiscoveryWatcher:
         if state_change in (ServiceStateChange.Added, ServiceStateChange.Updated):
             # Resolve in a task — async_request blocks the handler if awaited
             # synchronously and we don't want to stall mDNS dispatch.
-            asyncio.create_task(self._resolve_wled(service_type, name))
+            task = asyncio.create_task(self._resolve_wled(service_type, name))
+            self._resolve_tasks.add(task)
+            task.add_done_callback(self._on_resolve_done)
         elif state_change == ServiceStateChange.Removed:
             entry = self._wled_seen.pop(name, None)
             if entry is not None and not self._is_configured(entry.url):
                 self._emit("device_lost", entry)
 
+    def _on_resolve_done(self, task: "asyncio.Task") -> None:
+        """Release the strong task reference and log any resolve failure."""
+        self._resolve_tasks.discard(task)
+        if task.cancelled():
+            return
+        exc = task.exception()
+        if exc is not None:
+            logger.debug("Discovery watcher: resolve task raised: %s", exc)
+
     async def _resolve_wled(self, service_type: str, name: str) -> None:
         if self._aiozc is None:
             return
diff --git a/server/src/ledgrab/core/devices/wled_client.py b/server/src/ledgrab/core/devices/wled_client.py
index 4f6ec5a..cf4aa8b 100644
--- a/server/src/ledgrab/core/devices/wled_client.py
+++ b/server/src/ledgrab/core/devices/wled_client.py
@@ -453,8 +453,15 @@ class WLEDClient(LEDClient):
                 ],
             }
 
-            logger.debug(f"Sending {len(pixels)} LEDs via HTTP ({len(indexed_pixels)} values)")
-            logger.debug(f"Payload size: ~{len(str(payload))} bytes")
+            # ``str(payload)`` previously stringified the entire indexed
+            # array on every send to report a byte estimate; that was the
+            # hot path. Drop the size readout — the LED count + indexed
+            # value count is enough to interpret traffic and is O(1).
+            logger.debug(
+                "Sending %d LEDs via HTTP (%d indexed values)",
+                len(pixels),
+                len(indexed_pixels),
+            )
 
             await self._request("POST", "/json/state", json_data=payload)
             logger.debug("Successfully sent pixel colors via HTTP")
diff --git a/server/src/ledgrab/core/devices/wled_provider.py b/server/src/ledgrab/core/devices/wled_provider.py
index 039753b..144add3 100644
--- a/server/src/ledgrab/core/devices/wled_provider.py
+++ b/server/src/ledgrab/core/devices/wled_provider.py
@@ -98,11 +98,18 @@ class WLEDDeviceProvider(LEDDeviceProvider):
             dict with 'led_count' key.
 
         Raises:
+            ValueError: Unsupported scheme or invalid LED count.
             httpx.ConnectError: Device unreachable.
             httpx.TimeoutException: Connection timed out.
-            ValueError: Invalid LED count.
         """
         url = _normalize_url(url)
+        # Reject anything that isn't plain HTTP(S). url_scheme.infer_http_scheme
+        # passes non-HTTP schemes through untouched ("javascript:", "file:",
+        # "data:", etc.); without this guard those would reach httpx and
+        # surface as opaque transport errors at best, or be silently misused
+        # at worst.
+        if not url.lower().startswith(("http://", "https://")):
+            raise ValueError(f"WLED URL must use http:// or https:// scheme (got {url!r})")
         async with httpx.AsyncClient(timeout=5) as client:
             response = await client.get(_join(url, "/json/info"))
             response.raise_for_status()
diff --git a/server/src/ledgrab/core/mqtt/mqtt_runtime.py b/server/src/ledgrab/core/mqtt/mqtt_runtime.py
index 78f32b7..a9f4601 100644
--- a/server/src/ledgrab/core/mqtt/mqtt_runtime.py
+++ b/server/src/ledgrab/core/mqtt/mqtt_runtime.py
@@ -49,6 +49,32 @@ class MQTTRuntime:
         # Pending publishes queued while disconnected
         self._publish_queue: asyncio.Queue = asyncio.Queue(maxsize=1000)
 
+        # Strong references for fire-and-forget callback dispatch tasks.
+        # Python 3.11+ may GC bare ``asyncio.create_task(...)`` results mid-
+        # flight, so we hold each task until it completes and surface any
+        # exception via the done-callback.
+        self._dispatch_tasks: Set[asyncio.Task] = set()
+
+        # Compiled ``aiomqtt.Topic`` cache, keyed by the subscription pattern
+        # string. The previous dispatch loop re-parsed every pattern on
+        # every incoming message — on a chatty broker with many wildcards
+        # that adds up fast.
+        self._compiled_topics: Dict[str, aiomqtt.Topic] = {}
+
+    def _on_dispatch_done(self, task: asyncio.Task) -> None:
+        """Drop the strong reference and surface any callback exception."""
+        self._dispatch_tasks.discard(task)
+        if task.cancelled():
+            return
+        exc = task.exception()
+        if exc is not None:
+            logger.error(
+                "MQTT async callback raised (%s): %s",
+                self._source_id,
+                exc,
+                exc_info=exc,
+            )
+
     @property
     def is_connected(self) -> bool:
         return self._connected
@@ -84,6 +110,14 @@ class MQTTRuntime:
             logger.debug("MQTT runtime task cancelled: %s", self._source_id)
         self._task = None
         self._connected = False
+        # Cancel any in-flight async dispatch callbacks. Without this they
+        # would keep running past the runtime's logical end of life and
+        # could fire callbacks on a stopped subscriber.
+        for task in list(self._dispatch_tasks):
+            task.cancel()
+        if self._dispatch_tasks:
+            await asyncio.gather(*self._dispatch_tasks, return_exceptions=True)
+        self._dispatch_tasks.clear()
         logger.info("MQTT runtime stopped: %s", self._source_id)
 
     def update_config(self, source: MQTTSource) -> None:
@@ -167,13 +201,23 @@ class MQTTRuntime:
                     for topic in self._subscriptions:
                         await client.subscribe(topic)
 
-                    # Drain pending publishes
+                    # Drain pending publishes. A single publish failing
+                    # (broker rejection, oversized message) must not lose
+                    # the rest of the queue — log and continue with the next.
                     while not self._publish_queue.empty():
                         try:
                             t, p, r, q = self._publish_queue.get_nowait()
-                            await client.publish(t, p, retain=r, qos=q)
-                        except Exception:
+                        except asyncio.QueueEmpty:
                             break
+                        try:
+                            await client.publish(t, p, retain=r, qos=q)
+                        except Exception as exc:
+                            logger.warning(
+                                "MQTT drain publish failed (%s -> %s): %s",
+                                self._source_id,
+                                t,
+                                exc,
+                            )
 
                     # Message receive loop
                     async for msg in client.messages:
@@ -183,13 +227,21 @@ class MQTTRuntime:
                         )
                         self._topic_cache[topic_str] = payload_str
 
-                        # Dispatch to callbacks
+                        # Dispatch to callbacks. Pattern objects are cached
+                        # per subscription string to avoid re-parsing them on
+                        # every received message.
                         for sub_topic, callbacks in self._subscriptions.items():
-                            if aiomqtt.Topic(sub_topic).matches(msg.topic):
+                            compiled = self._compiled_topics.get(sub_topic)
+                            if compiled is None:
+                                compiled = aiomqtt.Topic(sub_topic)
+                                self._compiled_topics[sub_topic] = compiled
+                            if compiled.matches(msg.topic):
                                 for cb in callbacks:
                                     try:
                                         if asyncio.iscoroutinefunction(cb):
-                                            asyncio.create_task(cb(topic_str, payload_str))
+                                            task = asyncio.create_task(cb(topic_str, payload_str))
+                                            self._dispatch_tasks.add(task)
+                                            task.add_done_callback(self._on_dispatch_done)
                                         else:
                                             cb(topic_str, payload_str)
                                     except Exception as e:
diff --git a/server/src/ledgrab/core/processing/mapped_stream.py b/server/src/ledgrab/core/processing/mapped_stream.py
index e219e61..9e29d10 100644
--- a/server/src/ledgrab/core/processing/mapped_stream.py
+++ b/server/src/ledgrab/core/processing/mapped_stream.py
@@ -2,6 +2,7 @@
 
 import threading
 import time
+from collections import OrderedDict
 from typing import Dict, List, Optional
 
 import numpy as np
@@ -11,6 +12,11 @@ from ledgrab.utils import get_logger
 
 logger = get_logger(__name__)
 
+# Cap the (src_len, dst_len) resize cache. Each entry holds two ``np.linspace``
+# arrays plus a per-zone ``uint8`` scratch buffer, which used to grow without
+# bound under hot reconfigure storms.
+_RESIZE_CACHE_MAX = 16
+
 
 class MappedColorStripStream(ColorStripStream):
     """Places multiple ColorStripStreams side-by-side at distinct LED ranges.
@@ -46,8 +52,11 @@ class MappedColorStripStream(ColorStripStream):
 
         # zone_index -> (source_id, consumer_id, stream)
         self._sub_streams: Dict[int, tuple] = {}
-        # (src_len, dst_len) -> (src_x, dst_x, buffer) cache for zone resizing
-        self._resize_cache: Dict[tuple, tuple] = {}
+        # (src_len, dst_len) -> (src_x, dst_x, buffer) cache for zone resizing.
+        # An ``OrderedDict`` with eviction keeps memory bounded if device
+        # configurations fluctuate at runtime (each unique pair adds two
+        # linspace arrays + a per-zone reusable uint8 buffer).
+        self._resize_cache: "OrderedDict[tuple, tuple]" = OrderedDict()
         self._sub_lock = threading.Lock()  # guards _sub_streams access across threads
 
     # ── ColorStripStream interface ──────────────────────────────
@@ -229,6 +238,14 @@ class MappedColorStripStream(ColorStripStream):
                                     np.empty((zone_len, 3), dtype=np.uint8),
                                 )
                                 self._resize_cache[rkey] = cached
+                                # Drop the least-recently-inserted entry once
+                                # we hit the cap. 16 entries comfortably covers
+                                # any realistic zone/source layout — pathological
+                                # reconfigure storms used to grow this forever.
+                                if len(self._resize_cache) > _RESIZE_CACHE_MAX:
+                                    self._resize_cache.popitem(last=False)
+                            else:
+                                self._resize_cache.move_to_end(rkey)
                             src_x, dst_x, resized = cached
                             for ch in range(3):
                                 np.copyto(
diff --git a/server/src/ledgrab/core/processing/processed_stream.py b/server/src/ledgrab/core/processing/processed_stream.py
index 6689e95..17e3e09 100644
--- a/server/src/ledgrab/core/processing/processed_stream.py
+++ b/server/src/ledgrab/core/processing/processed_stream.py
@@ -160,9 +160,11 @@ class ProcessedColorStripStream(ColorStripStream):
                 self._resolve_count = 0
                 self._resolve_filters()
 
-            colors = None
-            if self._input_stream:
-                colors = self._input_stream.get_latest_colors()
+            # Bind to a local first — ``update_source()`` may swap or null
+            # out ``_input_stream`` between the check and the read on a
+            # different thread.
+            inp = self._input_stream
+            colors = inp.get_latest_colors() if inp is not None else None
 
             if colors is not None and self._filters:
                 for flt in self._filters:
diff --git a/server/src/ledgrab/core/processing/processor_manager.py b/server/src/ledgrab/core/processing/processor_manager.py
index d73bec0..773e99f 100644
--- a/server/src/ledgrab/core/processing/processor_manager.py
+++ b/server/src/ledgrab/core/processing/processor_manager.py
@@ -38,6 +38,7 @@ from ledgrab.storage.picture_source_store import PictureSourceStore
 from ledgrab.storage.postprocessing_template_store import PostprocessingTemplateStore
 from ledgrab.storage.template_store import TemplateStore
 from ledgrab.storage.value_source_store import ValueSourceStore
+from ledgrab.storage.http_endpoint_store import HTTPEndpointStore
 from ledgrab.storage.asset_store import AssetStore
 from ledgrab.core.processing.sync_clock_manager import SyncClockManager
 from ledgrab.core.weather.weather_manager import WeatherManager
@@ -74,6 +75,7 @@ class ProcessorDependencies:
     mqtt_manager: Optional[Any] = None  # MQTTManager
     game_event_bus: Optional[Any] = None  # GameEventBus
     audio_processing_template_store: Optional[Any] = None  # AudioProcessingTemplateStore
+    http_endpoint_store: Optional[HTTPEndpointStore] = None
 
 
 @dataclass
@@ -169,6 +171,7 @@ class ProcessorManager(AutoRestartMixin, DeviceHealthMixin, DeviceTestModeMixin)
                 event_bus=deps.game_event_bus,
                 audio_processing_template_store=deps.audio_processing_template_store,
                 sync_clock_manager=deps.sync_clock_manager,
+                http_endpoint_store=deps.http_endpoint_store,
             )
             if deps.value_source_store
             else None
diff --git a/server/src/ledgrab/core/processing/video_stream.py b/server/src/ledgrab/core/processing/video_stream.py
index c9b7100..b311c25 100644
--- a/server/src/ledgrab/core/processing/video_stream.py
+++ b/server/src/ledgrab/core/processing/video_stream.py
@@ -37,6 +37,33 @@ def is_youtube_url(url: str) -> bool:
     return any(p.search(url) for p in _YT_PATTERNS)
 
 
+# Network schemes accepted by ``cv2.VideoCapture``. ``file://`` is intentionally
+# excluded — local files are supported via plain path strings (no scheme), so
+# explicit ``file://`` requests can only be an attempt to coerce FFmpeg into
+# loading something the path-string code path would reject. ``concat:``,
+# ``gopher://``, ``crypto:``, etc. are not allowed.
+_ALLOWED_NETWORK_SCHEMES: tuple[str, ...] = ("http", "https", "rtsp", "rtsps")
+
+
+def _assert_video_url_allowed(url: str) -> None:
+    """Reject video URLs that use anything other than a vetted scheme.
+
+    OpenCV/FFmpeg supports many esoteric input protocols (``concat:``,
+    ``gopher://``, ``crypto:``, ``udp://``, ``async:``, …). Some can read
+    arbitrary host files or pivot to internal addresses when the caller
+    can influence the URL. Tighten the input to the schemes we actually
+    advertise. URLs without a scheme are accepted as local-file paths.
+    """
+    if "://" not in url:
+        return  # plain local path — OpenCV resolves against the working dir
+    scheme = url.split("://", 1)[0].lower()
+    if scheme not in _ALLOWED_NETWORK_SCHEMES:
+        raise RuntimeError(
+            f"Refusing to open video with unsupported scheme {scheme!r}; "
+            f"allowed: {', '.join(_ALLOWED_NETWORK_SCHEMES)} or a local file path."
+        )
+
+
 def resolve_youtube_url(url: str, resolution_limit: Optional[int] = None) -> str:
     """Resolve a YouTube URL to a direct stream URL using yt-dlp."""
     try:
@@ -185,10 +212,14 @@ class VideoCaptureLiveStream(LiveStream):
         if self._running:
             return
 
-        # Resolve YouTube URL if needed
+        # Resolve YouTube URL if needed. Validate AFTER resolution too, so a
+        # malicious yt-dlp result (or a redirect we don't expect) can't slip
+        # through with an unsupported scheme.
         actual_url = self._original_url
+        _assert_video_url_allowed(actual_url)
         if is_youtube_url(actual_url):
             actual_url = resolve_youtube_url(actual_url, self._resolution_limit)
+            _assert_video_url_allowed(actual_url)
         self._resolved_url = actual_url
 
         # Open capture
diff --git a/server/src/ledgrab/core/processing/wled_target_processor.py b/server/src/ledgrab/core/processing/wled_target_processor.py
index c3b5f41..4551fb1 100644
--- a/server/src/ledgrab/core/processing/wled_target_processor.py
+++ b/server/src/ledgrab/core/processing/wled_target_processor.py
@@ -224,7 +224,8 @@ class WledTargetProcessor(TargetProcessor):
 
         self._is_running = False
 
-        # Cancel task
+        # Cancel task. The cancellation is awaited above, so the prior
+        # 50 ms ``asyncio.sleep`` here was pure dead time on every stop().
         if self._task:
             self._task.cancel()
             try:
@@ -233,7 +234,6 @@ class WledTargetProcessor(TargetProcessor):
                 logger.debug("WLED target processor task cancelled")
                 pass
             self._task = None
-            await asyncio.sleep(0.05)
 
         # Restore device state (only if auto_shutdown is enabled)
         if self._led_client and self._device_state_before:
diff --git a/server/src/ledgrab/storage/mqtt_source.py b/server/src/ledgrab/storage/mqtt_source.py
index 0f5d4c4..ddfbec7 100644
--- a/server/src/ledgrab/storage/mqtt_source.py
+++ b/server/src/ledgrab/storage/mqtt_source.py
@@ -9,6 +9,8 @@ from dataclasses import dataclass, field
 from datetime import datetime, timezone
 from typing import List, Optional
 
+from ledgrab.utils import secret_box
+
 
 def _parse_common(data: dict) -> dict:
     """Extract common fields from a dict, parsing timestamps."""
@@ -52,13 +54,16 @@ class MQTTSource:
     icon_color: str = ""
 
     def to_dict(self) -> dict:
+        # Always persist the broker password in encrypted envelope form. If
+        # the field already contains an envelope, ``encrypt()`` is a no-op.
+        stored_password = secret_box.encrypt(self.password) if self.password else ""
         d = {
             "id": self.id,
             "name": self.name,
             "broker_host": self.broker_host,
             "broker_port": self.broker_port,
             "username": self.username,
-            "password": self.password,
+            "password": stored_password,
             "client_id": self.client_id,
             "base_topic": self.base_topic,
             "description": self.description,
@@ -75,12 +80,17 @@ class MQTTSource:
     @staticmethod
     def from_dict(data: dict) -> "MQTTSource":
         common = _parse_common(data)
+        # Decrypt at load time so consumers see plaintext via ``.password``.
+        # Legacy plaintext rows pass through unchanged — the next save will
+        # write them back in encrypted form.
+        raw_password = data.get("password", "")
+        password = secret_box.decrypt(raw_password) if raw_password else ""
         return MQTTSource(
             **common,
             broker_host=data.get("broker_host", "localhost"),
             broker_port=int(data.get("broker_port", 1883)),
             username=data.get("username", ""),
-            password=data.get("password", ""),
+            password=password,
             client_id=data.get("client_id", "ledgrab"),
             base_topic=data.get("base_topic", "ledgrab"),
             icon=data.get("icon", ""),
diff --git a/server/src/ledgrab/storage/mqtt_source_store.py b/server/src/ledgrab/storage/mqtt_source_store.py
index fdabcac..2f6b3a3 100644
--- a/server/src/ledgrab/storage/mqtt_source_store.py
+++ b/server/src/ledgrab/storage/mqtt_source_store.py
@@ -7,7 +7,7 @@ from typing import List, Optional
 from ledgrab.storage.base_sqlite_store import BaseSqliteStore
 from ledgrab.storage.database import Database
 from ledgrab.storage.mqtt_source import MQTTSource
-from ledgrab.utils import get_logger
+from ledgrab.utils import get_logger, secret_box
 
 logger = get_logger(__name__)
 
@@ -20,6 +20,41 @@ class MQTTSourceStore(BaseSqliteStore[MQTTSource]):
 
     def __init__(self, db: Database):
         super().__init__(db, MQTTSource.from_dict)
+        self._migrate_plaintext_passwords()
+
+    def _migrate_plaintext_passwords(self) -> None:
+        """Encrypt any stored MQTT broker passwords still in plaintext at rest.
+
+        Mirrors the HA-token migration: inspect raw DB rows, re-save items
+        that lack the encryption envelope so the next persistence pass
+        writes them in encrypted form.
+        """
+        migrated = 0
+        try:
+            rows = self._db.load_all(self._table_name)
+        except Exception as exc:
+            logger.error("Could not inspect rows for MQTT password migration: %s", exc)
+            return
+        for row in rows:
+            sid = row.get("id")
+            raw_pw = row.get("password", "") or ""
+            if not sid or not raw_pw:
+                continue
+            if secret_box.is_encrypted(raw_pw):
+                continue
+            source = self._items.get(sid)
+            if source is None:
+                continue
+            try:
+                self._save_item(sid, source)
+                migrated += 1
+            except Exception as exc:
+                logger.error("Failed to migrate MQTT password for %s: %s", sid, exc)
+        if migrated:
+            logger.warning(
+                "MIGRATION: encrypted %d plaintext MQTT broker password(s) at rest.",
+                migrated,
+            )
 
     # Backward-compatible aliases
     get_all_sources = BaseSqliteStore.get_all
diff --git a/server/src/ledgrab/utils/__init__.py b/server/src/ledgrab/utils/__init__.py
index 42466a5..43b1b65 100644
--- a/server/src/ledgrab/utils/__init__.py
+++ b/server/src/ledgrab/utils/__init__.py
@@ -1,13 +1,15 @@
 """Utility functions and helpers."""
 
-from .file_ops import atomic_write_json
+from .file_ops import atomic_write_json, read_upload_capped
 from .logger import setup_logging, get_logger
 from .monitor_names import get_monitor_names, get_monitor_name, get_monitor_refresh_rates
 from .timer import high_resolution_timer
 from .log_broadcaster import broadcaster as log_broadcaster, install_broadcast_handler
+from .url_scheme import infer_http_scheme
 
 __all__ = [
     "atomic_write_json",
+    "read_upload_capped",
     "setup_logging",
     "get_logger",
     "get_monitor_names",
@@ -16,4 +18,5 @@ __all__ = [
     "high_resolution_timer",
     "log_broadcaster",
     "install_broadcast_handler",
+    "infer_http_scheme",
 ]
diff --git a/server/src/ledgrab/utils/file_ops.py b/server/src/ledgrab/utils/file_ops.py
index 0d7edf1..9e2cb8d 100644
--- a/server/src/ledgrab/utils/file_ops.py
+++ b/server/src/ledgrab/utils/file_ops.py
@@ -5,10 +5,40 @@ import logging
 import os
 import tempfile
 from pathlib import Path
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from fastapi import UploadFile
 
 logger = logging.getLogger(__name__)
 
 
+_UPLOAD_CHUNK_SIZE = 1 * 1024 * 1024  # 1 MiB
+
+
+async def read_upload_capped(file: "UploadFile", max_size: int) -> bytes:
+    """Read an uploaded file in chunks, refusing to buffer past ``max_size``.
+
+    A plain ``await file.read()`` will allocate the entire upload body before
+    any size check runs, so a 1 GB upload still costs 1 GB of memory even
+    against a 50 MB limit. This helper streams the read and aborts as soon
+    as the accumulated size exceeds the cap.
+
+    Raises:
+        ValueError: When the upload exceeds *max_size*. The caller decides
+            how to translate the exception (typically HTTP 400/413).
+    """
+    buf = bytearray()
+    while True:
+        chunk = await file.read(_UPLOAD_CHUNK_SIZE)
+        if not chunk:
+            break
+        if len(buf) + len(chunk) > max_size:
+            raise ValueError(f"Upload exceeds maximum allowed size of {max_size} bytes")
+        buf.extend(chunk)
+    return bytes(buf)
+
+
 def atomic_write_json(file_path: Path, data: dict, indent: int = 2) -> None:
     """Write JSON data to file atomically via temp file + rename.
 
diff --git a/server/src/ledgrab/utils/safe_source.py b/server/src/ledgrab/utils/safe_source.py
index 8f4a012..2dfeef8 100644
--- a/server/src/ledgrab/utils/safe_source.py
+++ b/server/src/ledgrab/utils/safe_source.py
@@ -20,6 +20,8 @@ from urllib.parse import urlparse
 import httpx
 from fastapi import HTTPException
 
+from ledgrab.utils.net_classify import is_blocked_for_ssrf
+
 
 # Image file extensions considered safe to serve
 _IMAGE_EXTENSIONS = frozenset(
@@ -38,19 +40,13 @@ _IMAGE_EXTENSIONS = frozenset(
 
 
 def _is_blocked_ip(ip: str) -> bool:
-    """Return True when *ip* belongs to a category we refuse to fetch from."""
-    try:
-        addr = ipaddress.ip_address(ip)
-    except ValueError:
-        return True  # unparseable → block
-    return (
-        addr.is_private
-        or addr.is_loopback
-        or addr.is_link_local
-        or addr.is_reserved
-        or addr.is_multicast
-        or addr.is_unspecified
-    )
+    """Return True when *ip* belongs to a category we refuse to fetch from.
+
+    Thin wrapper preserved for the local test suite. The actual policy now
+    lives in :func:`ledgrab.utils.net_classify.is_blocked_for_ssrf` so it
+    can't drift away from the related ``url_scheme`` / ``auth`` modules.
+    """
+    return is_blocked_for_ssrf(ip)
 
 
 def _resolve_hostname(hostname: str) -> Iterable[str]:
@@ -67,6 +63,11 @@ def _resolve_hostname(hostname: str) -> Iterable[str]:
 def validate_image_url(url: str) -> None:
     """Validate that *url* is safe to fetch.
 
+    Strict SSRF policy — blocks all private / loopback / link-local /
+    reserved / multicast / unspecified IPs. Intended for fetches of
+    user-supplied URLs that should reach the *public* internet only
+    (image sources, weather APIs, etc.).
+
     Checks:
     - Scheme is http/https
     - Hostname is present
@@ -74,6 +75,25 @@ def validate_image_url(url: str) -> None:
     - DNS resolves to non-private, non-loopback, non-link-local, non-reserved,
       non-multicast addresses (SSRF protection)
     """
+    _validate_url(url, allow_private=False)
+
+
+def validate_polling_url(url: str) -> None:
+    """Validate that *url* is safe to poll from an automation trigger.
+
+    Relaxed SSRF policy — allows PRIVATE (LAN) IPs so users can target
+    devices on their own network (Plex on 192.168.x.x, Home Assistant
+    on 10.x.x.x). Still blocks LOOPBACK (protects the server's own
+    admin ports), LINK_LOCAL (blocks 169.254.169.254 cloud-metadata
+    services), MULTICAST, RESERVED, and UNSPECIFIED.
+
+    Use this instead of :func:`validate_image_url` for any user-configured
+    HTTP polling target.
+    """
+    _validate_url(url, allow_private=True)
+
+
+def _validate_url(url: str, *, allow_private: bool) -> None:
     parsed = urlparse(url)
     if parsed.scheme not in ("http", "https"):
         raise HTTPException(
@@ -93,17 +113,41 @@ def validate_image_url(url: str) -> None:
         ips = _resolve_hostname(hostname)
 
     for ip in ips:
-        if _is_blocked_ip(ip):
+        if _ip_is_blocked(ip, allow_private=allow_private):
+            policy = (
+                "loopback / link-local / reserved / multicast"
+                if allow_private
+                else "private / loopback / link-local / reserved / multicast"
+            )
             raise HTTPException(
                 status_code=400,
                 detail=(
                     f"Refusing to fetch URL: hostname {hostname!r} resolves to "
-                    f"blocked address {ip} (private / loopback / link-local / "
-                    "reserved / multicast)"
+                    f"blocked address {ip} ({policy})"
                 ),
             )
 
 
+def _ip_is_blocked(ip: str, *, allow_private: bool) -> bool:
+    """Block-list predicate parameterised by whether PRIVATE is permitted."""
+    from ledgrab.utils.net_classify import HostCategory, classify_ip
+
+    category = classify_ip(ip)
+    always_block = {
+        HostCategory.LOOPBACK,
+        HostCategory.LINK_LOCAL,
+        HostCategory.MULTICAST,
+        HostCategory.RESERVED,
+        HostCategory.UNSPECIFIED,
+        HostCategory.UNPARSEABLE,
+    }
+    if category in always_block:
+        return True
+    if not allow_private and category == HostCategory.PRIVATE:
+        return True
+    return False
+
+
 def validate_image_path(file_path: str | Path) -> Path:
     """Validate a local file path points to a real image file.
 
@@ -165,3 +209,88 @@ async def safe_fetch(
             response.raise_for_status()
             return response
     raise HTTPException(status_code=400, detail=f"Too many redirects (max {max_hops})")
+
+
+# ---------------------------------------------------------------------------
+# Bounded safe request — for polling-style fetches that need streaming
+# + size cap + arbitrary method/headers. Used by the HTTP poll runtime.
+# ---------------------------------------------------------------------------
+
+
+# Hard cap to avoid OOM from polled endpoints returning huge bodies.
+# 1 MiB covers every realistic JSON status endpoint by orders of magnitude.
+_MAX_RESPONSE_BYTES = 1 * 1024 * 1024
+
+
+async def safe_request_bounded(
+    method: str,
+    url: str,
+    *,
+    headers: dict[str, str] | None = None,
+    timeout: float = 10.0,
+    max_bytes: int = _MAX_RESPONSE_BYTES,
+    allow_private: bool = True,
+) -> tuple[int, bytes, str | None]:
+    """Make a single HTTP request with SSRF validation and a body-size cap.
+
+    Validates the URL up-front (scheme + IP-block) and streams the response
+    body, aborting as soon as ``max_bytes`` is exceeded so a malicious or
+    misconfigured endpoint can't OOM the server.
+
+    ``allow_private`` selects the SSRF policy: ``True`` (default — for HTTP
+    polling against user-owned LAN devices) routes through
+    :func:`validate_polling_url`; ``False`` routes through
+    :func:`validate_image_url`'s strict public-only policy.
+
+    Note on DNS rebinding: this validates the URL hostname's resolved IPs
+    once, then httpx independently re-resolves to make the actual request.
+    The window between the two resolutions is short but not zero. True
+    IP-pinning (rewriting the URL to the literal IP + Host header) is a
+    project-wide concern that would also need to update ``safe_fetch`` and
+    every other outbound caller; tracked as a follow-up.
+
+    Returns:
+        ``(status_code, body_bytes, error_message)``. ``error_message`` is
+        ``None`` on success; on transport failure ``status_code`` is 0 and
+        ``body_bytes`` is empty.
+
+    Raises:
+        HTTPException: when the URL fails validation (4xx-style error
+        intended for callers that surface this directly to the user).
+    """
+    if allow_private:
+        validate_polling_url(url)
+    else:
+        validate_image_url(url)
+    method = method.upper()
+    headers = dict(headers or {})
+
+    try:
+        async with httpx.AsyncClient(timeout=timeout, follow_redirects=False) as client:
+            async with client.stream(method, url, headers=headers) as response:
+                chunks: list[bytes] = []
+                total = 0
+                truncated = False
+                async for chunk in response.aiter_bytes():
+                    if total + len(chunk) > max_bytes:
+                        chunks.append(chunk[: max_bytes - total])
+                        total = max_bytes
+                        truncated = True
+                        break
+                    chunks.append(chunk)
+                    total += len(chunk)
+                body = b"".join(chunks)
+                # Truncation is NOT an error — the partial body is returned
+                # for the caller to use (e.g. evaluate a JSON path against the
+                # first 1 MiB). Callers that care can detect it by comparing
+                # ``len(body) == max_bytes``. We only flag actual transport
+                # failures in the error slot.
+                _ = truncated
+                return response.status_code, body, None
+    except httpx.RequestError as exc:
+        # Never include `exc` repr in the message — some httpx errors include
+        # request URL + headers, which could leak auth tokens supplied by the
+        # caller. Type name is sufficient diagnostic.
+        return 0, b"", f"Request failed: {type(exc).__name__}"
+    except Exception as exc:
+        return 0, b"", f"Unexpected error: {type(exc).__name__}"
diff --git a/server/tests/e2e/test_backup_flow.py b/server/tests/e2e/test_backup_flow.py
index 31f7c51..ada889d 100644
--- a/server/tests/e2e/test_backup_flow.py
+++ b/server/tests/e2e/test_backup_flow.py
@@ -12,22 +12,28 @@ class TestBackupRestoreFlow:
     """A user backs up their configuration and restores it."""
 
     def _create_device(self, client, name="Backup Device") -> str:
-        resp = client.post("/api/v1/devices", json={
-            "name": name,
-            "url": "mock://backup",
-            "device_type": "mock",
-            "led_count": 30,
-        })
+        resp = client.post(
+            "/api/v1/devices",
+            json={
+                "name": name,
+                "url": "mock://backup",
+                "device_type": "mock",
+                "led_count": 30,
+            },
+        )
         assert resp.status_code == 201
         return resp.json()["id"]
 
     def _create_css(self, client, name="Backup CSS") -> str:
-        resp = client.post("/api/v1/color-strip-sources", json={
-            "name": name,
-            "source_type": "static",
-            "color": [255, 0, 0],
-            "led_count": 30,
-        })
+        resp = client.post(
+            "/api/v1/color-strip-sources",
+            json={
+                "name": name,
+                "source_type": "single_color",
+                "color": [255, 0, 0],
+                "led_count": 30,
+            },
+        )
         assert resp.status_code == 201
         return resp.json()["id"]
 
diff --git a/server/tests/test_api.py b/server/tests/test_api.py
index 3926f0e..91d0d5e 100644
--- a/server/tests/test_api.py
+++ b/server/tests/test_api.py
@@ -78,15 +78,27 @@ def test_get_displays(client):
 
 
 def test_openapi_docs(client):
-    """Test OpenAPI documentation is available."""
-    response = client.get("/openapi.json")
+    """Test OpenAPI documentation is available to authenticated clients."""
+    response = client.get("/openapi.json", headers=AUTH_HEADERS)
     assert response.status_code == 200
     data = response.json()
     assert data["info"]["version"] == __version__
 
 
 def test_swagger_ui(client):
-    """Test Swagger UI is available."""
-    response = client.get("/docs")
+    """Test Swagger UI is available to authenticated clients."""
+    response = client.get("/docs", headers=AUTH_HEADERS)
     assert response.status_code == 200
     assert "text/html" in response.headers["content-type"]
+
+
+def test_openapi_docs_requires_auth(client):
+    """OpenAPI surface must NOT be reachable without auth (info disclosure)."""
+    response = client.get("/openapi.json")
+    assert response.status_code == 401
+
+
+def test_swagger_ui_requires_auth(client):
+    """Swagger UI must NOT be reachable without auth."""
+    response = client.get("/docs")
+    assert response.status_code == 401