SONOFF S31 Smart Plug with Energy Monitoring, 15A WiFi Outlet Timer Function, Compatible Alexa, Google Home & IFTTT, ETL Certified, NO Hub Required, 2.4GHz Wi-Fi Only(4-Pack) White 4PCS TPB

Very easy to flash with esphome
Then it is all local. Wi-Fi connectivity good, though I’m not sure if I trust the current rating on the relay. Power monitoring surprisingly accurate

Good for Tasmota an Home Assistant
This product is really good due to possibility of firmware customization. I installed Tasmota immediatelly and have them on Home Assistant. It provides different parameters for proper energy comsumption monitoring. I will buy more of them.

Not as easy to connect to WiFI but pretty flexible overall
I primarily bought this since it is reported to have a chipset that can be flashed with Tasmota so if the company goes out of business or I decide I want complete autonomy, I can reflash the devices and go off line. I have not done this yet but at least have the choice. I have done it on other Sonoff devices with no issues.Anyway, this product is not easy to connect at all .. especially with iOS, many people will find it frustrating to use the App to connect. Sonoff should either fix this issue or just direct everyone to what they call “compatible mode” where you have to put the device in hotspot mode and type in a password. The password really is not necessary and with the difficulties in setting up in normal mode, they should just default to this and make it easier to connect. It does work but unless you are a tinkerer (enjoy the challenge of setting up home automation), I do not recommend this product and expect that Sonoff would see a lot of returns or at least customer support issues.I certainly don’t recommend the newer version (S40) which has the same issues but also cannot be re-flashed with Tasmota. I would recommend to Sonoff that you really try to understand your customer base … most of your customers buy due to the flexibility to be able to flash different firmware on to the device … OR expect it to work properly out of the box.Right now I use it with Ewelink and connect with Homebridge so I can run it with HomeKit. It’s a good alternative to paying a premium for HomeKit certified devices.

Tasmota-compatible Smart Plug as of December 2023. Hard to fit two side-by-side
Sonoff has been a longtime reliable vendor of Tasmota-compatible devices. Unfortunately, some of their newer devices such as the S40, make it more difficult to install Tasmota firmware. This S31 though is great, with one or two minor gripes.Firstly, it’s wonderful in that there’s no adhesive or ultrasonic welding in sight, and it’s assembled in multiple pieces held together with screws. One other major positive is that it does power monitoring with the CSE7766 which is a calibration-free electric energy measuring chip, accurate to +- 1%. It’s easy to disassemble it and put it back together again without breaking any plastic.Once inside, there are easy to access pads to solder or use a BDM frame and a jig. Then it’s a simple matter of connecting a serial programmer to your computer (another ESP8266 works, a Raspberry Pi works, or a dedicated FDTI USB dongle works), then going to the Tasmota Installer ESP Web Tools website, and hitting connect/upload. That flashes the Tasmota firmware onto the ESP inside the Sonoff S31 and then you’re done!As for my minor gripes about this product, one is that it’s slightly too large to fit two side by side in our outlets. The S31s are larger on the edge near the wall compared to the front, probably to make the molding process easier, but it’s a millimeter or two too large to have two sit comfortably next to one another. My other gripe only came about after experiencing the SwitchBot Smart Plug Mini, and it’s that the S31 power button is actually pretty small.All in all though, the S31s have been my go-to Tasmota smart switch for years, and while I’ll probably buy SwitchBots as long as they’re still flashable, this is a known good backup.