Smart plugs are probably the category I’ve tested the most and with good reason.  They are super versatile, vary in terms of features and design, and are a smart home staple.  The Onvis S4 Smart Plug is the first solely Matter over Thread device I’ve tested and it did not go smoothly at all, but I still recommend it.  Read on to find out why!

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Aren’t All Smart Plugs the Same?

• Matter over Thread connectivity
• Compact form factor
• Physical on/off button

Before you Get the Onvis S4 Smart Plug…

• Only Matter over Thread, no HomeKit-specific support
  • Requires Thread border router
  • Requires Matter controller
  • 15A / 1800W

Thread is Great, Matter is Not

If you are at all familiar with myHomeKithome, you no doubt have recognized my affinity for Thread in the smart home.  For me, it truly has been that “It just works!” Connectivity standard for my smart home.  The S4 integrates Thread just like The Eve Energy which is the only other Matter over Thread smart plug currently on the market.

If you’re not in the know, Thread is a low-energy, self-healing, mesh network designed specifically for the smart home.  It is fool-proof and requires absolutely no configuration or maintenance on the user end.  It does require a Thread border router which lets the local Thread network communicate with the outside world via WiFi.  In the Apple ecosystem, HomePod mini and HomePod gen 2, and a few different Apple TV 4K models act as Thread border routers.

The Onvis S4 acts as a Thread router.  The Thread Group who manages the protocol definitely needs to work on their naming scheme, but thankfully this shouldn’t matter much to you.  As a Thread router, the S4 communicates directly with your border router, but it also helps to relay messages from nearby Thread end node devices which is where you get your stability, reliability, and self-healing properties.  They are essentially middle management.

I have had absolutely ZERO issues with the Onvis S4 as a Thread device with it working exactly as it should.  I did, however, have some significant issues with it as a Matter device.  More specifically, a Matter over Thread device.  I do want to be clear though that the problem lies with Matter and not this particular accessory.  

I’m Over Matter over Thread

I first got my review unit in May of 2023 and when attempting to pair it to my Apple Home, I repeatedly received error messages that simply stated “Failed to Pair”.  I performed all the standard troubleshooting procedures resetting the device, restarting my pairing device and Apple Home hub / Thread border router, ensuring my primary Home hub was in fact one that supports Thread, and no luck.  I reached out to Onvis and received a replacement sample and got the exact same results.  The S4 showed up as a parable accessory, but simply failed to pair.

I then snagged another solely Matter over Thread accessory namely the Aqara Door & Window Sensor P2 and received the same “failed to pair” issue.  It was my assumption at that point that my Apple ID or Apple Home was just having issues with Matter.

I then grabbed my wife’s phone and tried to pair the S4 and, wouldn’t you know, it worked.  However, this seemed to be a fluke as I was not able to reproduce the results with the second S4, nor P2.

I then got the SwitchBot Hub 2 which is a Matter over WiFi device and nervously tried to pair it to Apple Home but much to my surprise, it paired on the first attempt.  All of this led me to believe that the problem stemmed from some issue with Matter over Thread devices.  As I did not really have time to hop on what would inevitably be a lengthy support ticket with Apple, I decided to just set this issue aside and come back to it later.  That later ended up being after the public iOS 17 release and upgrading to the iPhone 15 Pro Max which has a Thread radio on-board.

I tried pairing the S4 again and was shocked to find that it connected right out of the gate.  Unfortunately, I haven’t been able to figure out what exactly made this happen.  Was it simply having a new phone or one that has a Thread radio?  Was it iOS 17 or the 17.1 update?  Pure luck?  I still have no idea.  I do know that I have been able to replicate the results with a second S4 I have.

From my hours of research, I can also say that this is an extremely rare issue that you won’t be likely to experience and thankfully so because it was unbelievably frustrating.  In an odd turn of events, I unpaired my SwitchBot Hub 2, again Matter over WiFi, and tried to pair it again just to see and was met with the dreaded “failed to pair” error.  I tried to pair the Matter over WiFi Meross Smart Plug and it too joined the “failed to pair” ranks.

So ,despite the hype and allure of this shiny new standard, my advice is to stick with what you know works and that’s HomeKit-specific support, at least for now.  I suspect that Onvis has also picked up on this sentiment since the S4 is their sole device to support Matter despite now having a decent lineup of Thread-based accessories.

Can I Overlook the Matter?

This admittedly very uncommon issue is unfortunate since the Onvis S4 is a very solid smart plug.  For the vast majority of my use cases, I’m simply looking for a controller that has on/off functionality, so its lack of energy monitoring does not bear much weight.

The S4 is compact allowing for two to fit in a standard North American outlet which really seems like a given in 2023, but is something I cannot say about the Meross Matter Smart Plug.

How “smart” is this Onvis Smart Plug?

Regardless of whether you use it in Apple Home or in the Onvis Home app, you have the same essential functionality which is standard for a smart plug.  You get remote on/off control and the ability to schedule this control or add it to scenes with other smart devices, as well as being able to include it in automations.  Nothing outstanding, but I argue that it does not need to be.

How Accessible is This Smart Plug?

Smart plugs are a relatively vanilla smart home device at this point and this applies to their accessibility.  The S4 has a physical button which has very decent tactile and audible responsiveness.  Like the vast majority of others on the market, it does have an LED indicator that does not have any alternative means of communication.  It’s also really compact and not overly bulky.  Other than this there’s not a lot to say about the S4’s hardware accessibility.

The Onvis Home app unfortunately does not give us much in the way of screen reader support.  It is lacking semantic structure, has unlabeled buttons and other elements, and some elements that should be actionable are not.

The good news here is that with the S4 being a Matter-compatible device, we can bring it into our smart home platform of choice which tend to increase accessibility, at least for Apple Home users.

The Onvis Home app also does not offer any features outside of firmware updates that we don’t get in Apple Home so I’m OK with it, but this is not a “get out of jail free” card.

  Accessibility needs to be a priority for all manufacturers on both the hardware and software levels and not just because it makes their devices easier to use for people with disabilities.  Taking accessibility into account and making the proper adjustments improves the user experience for all users and ultimately results in a better product.

Does the Perfect Smart Plug Exist?

Probably not, but the Onvis S4 makes a strong showing.  It is snappy and reliable thanks to Thread.  It’s stealthy and practical with its minimalist design.  And, it’s pretty versatile with support for Matter.  Yes, Matter is still new and having some minor issues getting fully up and running, but this is not the S4’s fault.  Onvis certainly could have opted for direct Apple Home certification in addition to Matter, but this would have increased cost and potentially made this smart plug less attractive for consumers.  Yes, you can pay a little more and get the same essential features along with energy monitoring but if you don’t need it, why spend the extra scratch?