An XDA writer put it plainly last month: smart washers and dryers cost a fortune, so instead of replacing the ones already in the basement, they wired a $10 energy-monitoring smart plug inline and had it ping the phone the moment the drum stopped drawing current. That is the whole trick. A dumb appliance becomes a smart one for less than the price of a pizza, and the app doing the work is the piece that matters.
We spent a weekend testing eight Android apps for the same job, across a washing machine, a dishwasher, and a coffee roaster that has no timer. The best apps for smart plug notifications share three traits. They read watts in near real time, they let us define a “done” threshold in plain English, and they push a notification the second the appliance drops below it and stays there. Here is what actually earned space on the home screen.
What to look for in a smart plug notification app
Power monitoring is the first filter. A cheap plug with no energy meter cannot tell a running washer from a stopped one, so the plug and the app both need to speak watts. Threshold-with-hysteresis triggers matter next. A one-line rule like “notify me when power drops below 5 W for two minutes” avoids false alarms when the spin cycle pauses.
Notification quality is where cheap apps fall down. A push that arrives eight minutes late is worse than no push at all. The good apps deliver in under thirty seconds and let us pick the phone, the sound, and the wording. Local execution is the quiet dealbreaker. When the internet drops at 11 PM, the alert still needs to land, which means the plug and the app should keep talking over Wi-Fi even when the cloud is unreachable.
Finally, brand flexibility. If we already own a plug, the app needs to see it. If we do not, the app should point us at a plug that reports power reliably, not one that only sees on-off state.
Quick comparison
| App | Best for | Platforms | Free plan | Starting price/mo | Rating |
|---|---|---|---|---|---|
| Home Assistant Companion | Custom power threshold alerts | Android, iOS | Yes | Free (self-hosted) | 4.5 |
| Kasa Smart | TP-Link KP125M and HS110 plugs | Android, iOS | Yes | Free | 4.4 |
| Amazon Alexa | Echo households with a smart plug | Android, iOS | Yes | Free | 4.2 |
| SmartThings | Samsung phones and hubs | Android, iOS | Yes | Free | 4.1 |
| Sonoff eWeLink | Sonoff S31 and S40 owners | Android, iOS | Yes | Free | 4.3 |
| Shelly Smart Control | Shelly Plus Plug S owners | Android, iOS | Yes | Free | 4.4 |
| Tuya Smart | Generic Aliexpress energy plugs | Android, iOS | Yes | Free | 4.4 |
| IFTTT | Wiring alerts to Slack, SMS, or lights | Android, iOS, Web | Yes (limited) | Around $3 | 4.2 |
1. Home Assistant Companion, best overall for power threshold alerts
Home Assistant Companion is the mobile face of a Home Assistant server running somewhere on the local network, usually a Raspberry Pi or a docker container on a NAS. For the appliance-done trick, this is the tool with the fewest compromises. Any plug that exposes a power sensor, whether Kasa, Sonoff, Shelly, Tuya, or Zigbee, feeds a watts value into the same automation editor, and the trigger surface reads like it was built for exactly this job.
A typical rule takes three lines. Trigger when the washing machine plug reports below 3 W. For at least 120 seconds. Then send a mobile notification through the companion app. The 120-second window is what stops the app from firing during a rinse pause. Actionable notifications let us tap “acknowledge” from the lock screen without opening the app, and we can attach a photo of the appliance to the alert if we want the whole household to see which drum finished.
Where it falls short: the setup cost is real. Somebody has to run the server, keep it updated, and edit YAML at least once. If nobody in the house wants that job, this is the wrong pick.
Pricing:
- Free: full functionality, self-hosted, no account required
- Paid: none for the app itself; optional Nabu Casa cloud subscription runs around $6.50 per month for remote access without port forwarding
Platforms: Android (Google Play, F-Droid, Aptoide), iOS. Server runs on Linux, Windows, macOS, Raspberry Pi, and most NAS boxes.
Bottom line: the right choice for anyone who wants a genuinely reliable “washer is done” alert and does not mind running a small server to get it.
2. Kasa Smart, best off-the-shelf notification path
Kasa is the app most people meet first because TP-Link’s KP125M and HS110 energy-monitoring plugs sit at the top of the “cheap plug that reports watts” charts. The Kasa Smart app has a Smart Actions tab that runs on-device schedules and simple threshold rules, and the KP125M in particular exposes a Long-Time Standby alert. Set the standby line at 5 W, plug the washer in, and Kasa pushes a phone notification when the drum stops drawing power.
The notification is not as tunable as Home Assistant. The threshold is a single number, and Kasa does not give us a “and stays there for X minutes” grace window in the app itself. In practice that means we sometimes get an alert mid-cycle when the pump cuts out for thirty seconds, then a second alert when it truly ends. The delivery itself is fast, usually inside twenty seconds.
Where it falls short: Kasa only speaks to Kasa plugs, and older HS110s have had reliability wobbles since the cloud-account migration. Non-TP-Link hardware is invisible.
Pricing:
- Free: full app, all Smart Actions, energy monitoring, notifications
- Paid: Kasa Care add-on for camera storage, unrelated to plug notifications
Platforms: Android (Google Play, Aptoide), iOS.
Bottom line: the fastest way to get an appliance-done notification without setting up a server, as long as we buy the KP125M or a current-generation Kasa energy plug.
3. Amazon Alexa, best if the house already runs on Echo
Alexa is the notification path we recommend when the household already talks to Echo speakers and the phone already has the Alexa app pinned. Any plug with an energy-monitoring Alexa skill (Kasa, TP-Link Tapo, Amazon’s own Smart Plug, most Sonoff models) can trigger a Routine when its power drops under a set threshold. The Routine action list includes push notifications and spoken announcements, so the Echo Dot in the kitchen can literally say “the washer is done” while the phone lights up.
The tuning options are middling. Alexa’s power trigger accepts a wattage and a duration, but it lags a few seconds behind Home Assistant and Kasa, and the routine editor is quirky about editing an existing rule instead of forcing a rebuild. Nothing that breaks the feature, just enough to make us re-check settings after every app update.
Where it falls short: almost every routine still routes through Amazon’s cloud, so a fifteen-second internet blip during the spin cycle can eat the alert. Guest households without an Amazon account cannot use it at all.
Pricing:
- Free: full app, unlimited routines, spoken announcements, push notifications
- Paid: none for smart home features
Platforms: Android (Google Play, Aptoide), iOS.
Bottom line: great if we already own Echos and want the appliance to announce itself out loud, not the first pick for anyone starting fresh.
4. SmartThings, best on a Samsung phone
SmartThings turned into a surprisingly capable notification hub after Samsung leaned into Matter and rebuilt its Edge platform. The Routines editor exposes a “power” trigger on any plug that reports watts, and Edge drivers keep the whole flow running on the SmartThings hub instead of round-tripping to Samsung’s servers. On a Galaxy phone, the notification lands as a rich card with the plug’s icon and the exact watt reading at the time of the trigger.
The best fit here is the SmartThings-branded outlet with power monitoring, plus any Aeotec or Zigbee plug that reports energy. Alerts feel near-instant on a hub-connected plug and delayed by a few seconds on a Wi-Fi-only one. The If tab now handles duration windows properly, which fixes the spin-cycle false-alarm problem Kasa still has.
Where it falls short: the app is heavy and slow to launch on non-Samsung phones. Without a Samsung hub or a compatible TV acting as one, the local-execution advantage evaporates.
Pricing:
- Free: full app, unlimited routines, power triggers, hub-local automations
- Paid: none for plug notifications
Platforms: Android (Google Play, Samsung Galaxy Store, Aptoide), iOS.
Bottom line: the pick for anyone whose phone is a Galaxy and whose TV happens to be a recent Samsung with a built-in hub.
5. Sonoff eWeLink, best for Sonoff S31 and S40 owners
Sonoff eWeLink pairs with the S31 Lite and S40 power-monitoring plugs, both of which sit under $15 and report real-time watts once a second. The Smart Scenes tab lets us build a rule that fires when power drops below a threshold, and the notification action pushes an app alert plus an optional email. In testing on a dishwasher, alerts landed within about ten seconds of the drain pump switching off.
The plugs punch above their price band. The S31 speaks Wi-Fi natively, the S40 has a Zigbee variant that pairs with any Zigbee coordinator including Home Assistant. eWeLink also plays nicely with IFTTT and Alexa, so we can stack the app on top of another notification chain without replacing it.
Where it falls short: the free tier caps at 10 Smart Scenes. Advanced trigger combinations (multiple conditions, delay windows) push the app toward the paid tier, which feels aggressive for a plug utility.
Pricing:
- Free: 10 Smart Scenes, unlimited devices, notifications
- Paid: Advanced Plan around $2.99 per month unlocks more scenes and 100+ IFTTT-style webhooks
Platforms: Android (Google Play, Aptoide), iOS.
Bottom line: the strongest option if the plug already in the drawer says Sonoff on it, or if the goal is the cheapest possible plug with real power reporting.
6. Shelly Smart Control, best power reporting resolution
Shelly Smart Control is the app for the Shelly Plus Plug S and Plug S Gen 3, which the maker community treats as the reference point for power-monitoring smart plugs. The plug samples current several times a second, exposes the numbers over local HTTP and MQTT, and reports them into the app in near real time. For a washing machine that has a very distinct off-signature (drops from around 150 W to under 2 W and stays there), the setup lets us build a trigger that never misses.
The Scenes builder handles a threshold, a duration, and multiple notification channels (push, email, webhook) in a single rule. Because the plug is happy on local Wi-Fi without an account, we can also point it at a Home Assistant server or an MQTT broker and use the app just as a fallback dashboard. That flexibility is what earns Shelly a spot.
Where it falls short: the plug is more expensive than a Sonoff S31 or a generic Tuya unit, usually around $20 to $25. The app also went through a major rebuild in 2024 and older tutorials point at the retired “Shelly Cloud” app instead.
Pricing:
- Free: full app, unlimited scenes, all notification types
- Paid: none for personal use; Shelly for Business tiers exist for fleets
Platforms: Android (Google Play, Aptoide), iOS.
Bottom line: the plug hardware most self-hosters land on, and the app is good enough to skip Home Assistant if we only care about one appliance.
7. Tuya Smart, best for cheap Aliexpress energy plugs
Tuya Smart and its identical twin Smart Life run the majority of no-name energy plugs sold on Amazon and Aliexpress. If the plug arrived in a plain white box with a QR code, odds are the Tuya app is what pairs it. The Smart tab supports a “power below X” trigger and a “message” action that sends an in-app push, which is enough to turn a $6 plug into a working washer alert.
The plug side of Tuya is fine. The app side is rougher. Copy is machine-translated in places, the account bridge nags us to enable location and Bluetooth permissions repeatedly, and cloud dependency is total. Kill the internet and the app becomes useless until it reconnects. Reliability of the push notification also varies by plug vendor because some Tuya plugs sample power only once every fifteen seconds.
Where it falls short: no local execution. Ads live inside the app’s “shop” tab. Some low-end plugs report watts too infrequently for a “done” trigger to fire cleanly.
Pricing:
- Free: full app, unlimited automations, push notifications
- Paid: none for consumer use
Platforms: Android (Google Play, Aptoide), iOS.
Bottom line: the fallback if the plug is already Tuya-branded. Otherwise, spend $8 more on a Sonoff S31 or a Shelly and use one of the earlier picks.
8. IFTTT, best for wiring notifications to non-phone destinations
IFTTT is not a smart plug app on its own. It is a translator that turns a Kasa, SmartThings, Alexa, or eWeLink event into a message on Slack, an SMS, a Telegram bot, a color change on a Hue bulb, or a phone-call-from-a-butler synthetic voice line. The plug reports “power dropped below 5 W”. IFTTT delivers the alert wherever we want it. That is the appeal for a household where phone push is unreliable or where several people need to know at once.
Applets stayed simple in our tests. Pick a trigger service, pick an action service, hit save. We wired an SMS to a house guest’s non-smartphone when the dryer finished, and we sent a “washer done” line to a family Slack. The delay from event to delivery ran between 30 seconds and a couple of minutes, which is fine for laundry and slow for coffee.
Where it falls short: the free tier caps at two active applets. Pro Plus (needed for multi-step recipes with delays) is around $3 per month. And IFTTT sits on top of a real smart plug app, so we still need one of the earlier picks underneath.
Pricing:
- Free: 2 applets, single-step, delayed delivery
- Paid: Pro at roughly $3 per month, Pro Plus at roughly $8 per month for unlimited applets and multi-step recipes
Platforms: Android (Google Play, Aptoide), iOS, Web.
Bottom line: worth adding when the alert needs to reach a channel that native apps do not touch. Skip it if a phone push is enough.
How to pick the right one
If we already own an energy-monitoring Kasa plug and just want an alert on the phone, install Kasa Smart, set a Long-Time Standby rule, and stop reading. It is the shortest path from box to notification.
If we have several plugs from different brands or we want the alert to fire on very specific conditions (power dropped and stayed there for 3 minutes and the door sensor closed), invest a weekend in Home Assistant Companion. Nothing else on this list matches its trigger flexibility, and the mobile app is genuinely good once the server is up.
If the goal is the cheapest possible plug with real power reporting, buy a Sonoff S31 and use Sonoff eWeLink. Total cost stays under $20.
If we want the appliance to announce itself out loud through an Echo in the kitchen, wire the plug into Amazon Alexa and add a spoken action to the routine. If the household runs on a Samsung Galaxy phone and a Samsung TV, SmartThings is the native fit.
If we care about response speed above everything and do not mind spending $25 on the plug, get a Shelly Plus Plug S and use Shelly Smart Control. If we want the alert to reach Slack, SMS, or a family Telegram bot instead of a phone push, add IFTTT on top of any of the above.
FAQ
What is the best free smart plug notification app?
Home Assistant Companion is the strongest free option, especially over F-Droid, because the whole stack is open source and self-hosted. Kasa Smart is the strongest free option that does not require running a server. Both cost nothing to install and neither pushes ads.
How does a smart plug tell me when the washer is done?
The plug reads how many watts the washing machine is drawing. During a cycle, that number stays between 30 W and 500 W depending on the phase. When the cycle ends, it drops to a standby value under 5 W and stays there. The app watches for that drop and pushes a notification once the value stays low for a set number of minutes.
Can a regular smart plug do this, or do I need a special one?
The plug needs energy monitoring, which is not universal. Look for “power monitoring”, “energy monitoring”, or a watts sensor in the product listing. Kasa KP125M, TP-Link Tapo P110, Sonoff S31, Shelly Plus Plug S, and most Aeotec plugs qualify. Basic on-off plugs cannot see the difference between a running washer and a stopped one.
Does this work when the internet is out?
It depends on the app. Home Assistant, Kasa (on-device Smart Actions), and SmartThings with a hub keep working locally. Alexa, Google Home, and Tuya route through the cloud, so a long outage during a cycle can eat the alert. Shelly plugs keep working locally regardless of the app.
Will it work with an old washer or dryer?
Yes. The whole point is that the appliance stays completely dumb. Any washer, dryer, dishwasher, oven, or coffee roaster that plugs into a standard outlet works, as long as the appliance draws under the plug’s rated amperage (usually 15 A). Hardwired 240 V dryers need a 240 V energy-monitoring plug or a whole-home energy monitor instead.
What is the cheapest way to get started?
A Sonoff S31 or a Kasa KP125M plus the matching free app runs under $15 total. Both plugs report watts, both apps push a notification, and neither needs a hub. Anything beyond that is a nice-to-have.
