What still works when the internet goes down
Three different outages, three different answers. Knowing which one you are having is most of the diagnosis.
Three outages, not one#
People say "the internet is down" for three different failures that have three different blast radii. Diagnose which one you have before anything else.
| Failure | What is still up | What stops |
|---|---|---|
| WAN down (ISP or modem) | Your LAN, Wi-Fi, all radios, every local hub | Cloud control, voice, remote access, notifications, cloud cameras |
| Router or AP down | Radios that do not need the LAN: Zigbee, Z-Wave and Thread meshes, bound remotes | Everything IP based, including local hub apps, Matter over Wi-Fi, and Thread device discovery from your phone |
| Vendor cloud down, your internet fine | Everything local, plus every other vendor | Just that vendor's devices, app and voice integration |
The middle row surprises people. Your router is a bigger single point of failure than your ISP, because Matter over Wi-Fi, Thread border router discovery over mDNS, and your hub's own app all ride on it. A Zigbee mesh does not care about your router at all, which is a genuine, underrated argument for keeping some devices on a non-IP radio.
The third row is the one that has been getting more common. Google's global outage on 18 August 2026 lasted about twelve hours and left Nest hubs unresponsive while everyone's internet worked perfectly.
By device class#
The rule underneath the whole table: a device keeps doing whatever it was already told to do, and stops doing anything that requires a new decision from a machine you cannot reach.
| Device class | With a local hub | Cloud Wi-Fi device | Why |
|---|---|---|---|
| Lights on Zigbee, Z-Wave or Thread | Full control, automations, bound remotes | n/a | The command never leaves the house |
| Matter over Wi-Fi lights and plugs | Full local control | n/a | Matter's control path is local by design |
| Cloud Wi-Fi bulbs and plugs | Only if your hub has a local integration | App fails, physical switch works | The app talks to the vendor, not to the bulb |
| Wall switches and dimmers | Full control, and the paddle always works | Paddle works, app does not | The load is wired through the switch |
| Motion, contact, leak, temperature sensors | Report normally and trigger local rules | Nothing reaches you | Reports go to whichever machine subscribed to them |
| Smart locks (Zigbee, Z-Wave, Thread) | Lock, unlock, codes, local automations | Keypad and key work, app does not | Credentials are stored on the lock |
| Thermostats | Local schedule and control | Schedule runs, app and geofencing do not | Schedules are stored on the device |
| Cameras with local recording or RTSP | Live view and recording on your NVR | Nothing | See below |
| Cloud cameras and doorbells | Nothing, unless the hub pulls a local stream | Nothing, including the chime app | See below |
| Garage door openers | Depends entirely on the controller | Nothing | MyQ is the well-known case |
| Robot vacuums | Start and stop through Matter, if supported | Button on the robot only | Maps and scheduling are cloud features |
| Voice assistants | Nothing on Alexa or Google. Siri fails too | Nothing | Speech recognition is a cloud service |
| Smoke and CO alarms | The alarm itself always sounds | The alarm sounds, the phone alert does not | The siren is a local safety function |
Two entries deserve their own explanation, because they are the ones people argue about.
Why a cloud camera has no local fallback#
It feels like it should work. The camera is on your Wi-Fi, your phone is on the same Wi-Fi, and they are two hops apart. Yet the app shows a spinner.
Three things are in the way, and each one is enough on its own. First, discovery and authorization: the app does not know the camera's local address and would not trust it if it did, because the session is authorized by the vendor's account service, which is unreachable. Second, session negotiation: modern camera streaming uses WebRTC or a similar scheme, and both ends need a signaling server to exchange connection details before a single frame moves. That server is in the vendor's cloud. Third, the recording path: on a subscription camera the encoder's job is to push video upstream, and there is often no local storage and no local streaming endpoint to fall back to at all.
The fix is not a setting. It is a purchase decision: a camera with onboard storage plus an RTSP, ONVIF or HomeKit Secure Video path, or a proper NVR. Cameras and doorbells covers what to look for. Matter 1.5 added camera support in November 2025, but as of September 2026 SmartThings is the only major controller shipping it, so it changes less than the headlines suggest.
Why a Zigbee bulb still answers its wall remote#
Because nothing in that path is a computer you can lose. A Zigbee binding writes the target directly into the remote's binding table, so pressing the button transmits a command addressed at the bulb over the 802.15.4 radio. The coordinator is not consulted and no rule is evaluated. Zigbee2MQTT's documentation says it outright: bindings work even when the coordinator and the automation software are down. Z-Wave associations behave the same way.
This is the single most robust arrangement available in a smart home, and it costs nothing but ten minutes of setup. It is also invisible in most consumer apps, which is why so few people have it.
By platform#
Where automations execute is a property of the platform, not of your devices. This is the Local Control Index, our scored comparison of the seven mainstream platforms against a rubric published at /methodology/.
| Platform | Score /100 | Local app control on the LAN | Local automation execution | Survives a vendor shutdown | Why |
|---|---|---|---|---|---|
| Home Assistant | 100 | 20 / 20 | 20 / 20 | 15 / 15 | The reference implementation of local control. Cloud is an optional paid add-on for remote access and voice services, and everything works without it. |
| Hubitat Elevation | 87.5 | 20 / 20 | 20 / 20 | 15 / 15 | Rules run on the hub in milliseconds and survive an outage. Loses points only for having no local voice option and for requiring an account at registration. |
| Homey Pro | 62.5 | 10 / 20 | 20 / 20 | 7.5 / 15 | Automations are genuinely on-premise, but owners report the mobile app needing to reauthorize against the internet, which can lock you out mid-outage. Scored half on app control for that reason. |
| Apple Home | 60 | 20 / 20 | 20 / 20 | 7.5 / 15 | Automations run on the HomePod or Apple TV, so they survive an outage. Siri does not, there is no local API, and there is no way to export or back up your configuration. |
| Samsung SmartThings | 30 | 10 / 20 | 10 / 20 | 0 / 15 | Edge drivers execute on the hub, which is real local processing, but Samsung does not document which routines run locally during an outage. Scored half where the evidence is partial. |
| Google Home | 15 | 10 / 20 | 0 / 20 | 0 / 15 | Local Matter control covers lights, plugs and switches only. Routines and all voice remain cloud side, which the twelve hour outage in August 2026 demonstrated at scale. |
| Amazon Alexa | 5 | 0 / 20 | 0 / 20 | 0 / 15 | On-device voice processing was removed in March 2025 with no opt-out. Devices stay reachable at the protocol level, but nothing in the Alexa layer works without the internet. |
What that resolves to during an actual outage:
- Home Assistant: everything, including a fully local voice pipeline. The cloud subscription is only for remote access, bridging and backups.
- Hubitat: rules run on the hub in milliseconds and keep running. No local voice option.
- Homey Pro: Flows keep running locally, but owners report the mobile app periodically needing internet to reauthorize, so you may not be able to see or change anything while it is out.
- Apple Home: automations execute on the HomePod or Apple TV and survive. LAN control from an iPhone at home works. Siri, remote access, shared access and HomeKit Secure Video upload do not. Note that iPads are no longer supported as home hubs, so an iPad-only household has no automation during an outage.
- SmartThings: Edge drivers execute on the hub, which is real local processing, but Samsung does not document which Routines run locally. Treat partial as the honest answer.
- Google Home: local Matter control covers lights, plugs and switches only. Routines and all Gemini voice are cloud side.
- Alexa: devices stay reachable at the protocol level, but nothing in the Alexa layer works. Amazon removed on-device voice processing on 28 March 2025 with no opt-out, so even the wake word leads nowhere.
Run your own list through the outage audit to get this per device rather than per platform.
Designing for the outage you will actually have#
Most households do not need a bunker. They need four or five things to keep working and everything else to fail politely.
- Put the router, one AP and the hub on a UPS. A small unit covers the most common outage, which is a brief power blip rather than a day. Everything downstream of that is moot if the network is dark.
- Bind the lights people use in the dark. Bedside, hallway, top of the stairs.
- Keep the wall switches switching. A switch or dimmer beats a smart bulb anywhere a guest might reach for the wall.
- Buy locks that hold their credentials on the lock. A code that validates on the device works in an outage. A code validated in the cloud does not, and both designs are sold.
- Do not put anything with a physical consequence on rung four or five of the ladder in local vs cloud control: garage doors, gates, water valves, the only heat source in a cold house.
- Write down the manual override for each one. The key, the pull cord, the physical thermostat buttons. Tape the list inside a cupboard door.
Do smart lights work without Wi-Fi?
Zigbee, Z-Wave and Thread bulbs do not use your Wi-Fi at all, so they keep working with a local hub, and a bound wall remote keeps working even without the hub. Wi-Fi bulbs need your access point to be up. If the access point is up and only your internet is down, a Matter Wi-Fi bulb still responds locally, while a cloud-only Wi-Fi bulb usually does not.
Does Alexa work without internet?
No, in any meaningful sense. Speech recognition runs in Amazon's cloud, and the on-device processing option that three Echo models once had was removed on 28 March 2025 with no opt-out. An Echo acting as a Zigbee or Thread hub still passes traffic at the protocol level, but you cannot ask it to do anything. Siri and Gemini for Home are cloud services too.
Does Matter work without the internet?
Yes for control. A Matter controller and a Matter device share credentials in a fabric and talk over local IP on your own network, with no cloud in the path. What still needs the internet is anything outside the control path: voice, remote access, notifications, firmware updates, and sometimes initial commissioning through a vendor app. Your router still has to be running, and Google's Matter setup requires IPv6 on it.
Why did my Thread devices go unresponsive when only my internet dropped?
Almost always this is a coincidence of timing rather than a cause. Thread is entirely local and a border router keeps routing without an upstream connection. What usually happened is that the router rebooted or a mesh node reset, and your controller lost the mDNS advertisements it uses to find Thread devices. Start with your router and your controller's discovery, not with the ISP.
Will my smart lock still open in an outage?
The key works, and on any lock worth buying the keypad works too, because the codes are stored on the lock and validated by its own firmware. What stops is remote unlocking, notifications, and any auto-unlock that depends on a cloud presence service. Check before buying whether codes are stored locally or checked against a server, because both designs are sold.
Do my cameras record anything during an outage?
Only if they have local storage. A camera with a microSD card or an NVR keeps recording, and the footage is there when the link returns. A subscription camera that streams to the vendor loses that window entirely, and you usually cannot view it live on your own Wi-Fi either, because the app needs the vendor's authorization and signaling servers to open a session.
Is a hub worth buying just for outage resilience?
If you already own more than a handful of devices, yes, and it usually buys speed and privacy at the same time. The honest counterpoint is that a hub is one more box to maintain and back up. If most of what you own is already Wi-Fi and cloud-bound, a hub alone will not rescue it, and replacing a few key devices matters more.
What about power cuts rather than internet cuts?
Different problem, same discipline. Battery devices carry on, mains devices do not, and mesh networks lose their relays, so a Zigbee or Thread network can fragment even where a few devices still have power. A UPS on the router, one access point and the hub covers short cuts. For long ones, the only things that matter are the manual overrides.
Primary sources
Specification and vendor documentation we checked while writing this page. Where a claim depends on firmware behaviour rather than a published spec, the page says so inline.