Home Assistant with ESPHome, or Plynx for the board on your bench

Two different questions

Home Assistant answers “how do I run my whole house from one place?” It is free and open source, it runs on your own hardware, it keeps control local, and it connects to more commercial devices than any other project. Flash an ESP32 with ESPHome and your own sensor shows up next to the lights you bought in a shop. For that question it is the right answer.

Plynx answers a smaller question: “I built this one thing and I want it on my phone.” The app is the interface. You add a board, the app writes the sketch for you, and you drag a widget onto the canvas and bind it to a pin. There is nothing to install on a server and nothing to keep updated, because there is very little there.

Where Plynx is the better fit

Home Assistant can put a single board on your phone too, but you pay for a platform first. You install it, you keep it updated, you learn its vocabulary (entities, integrations, automations, and usually a bit of YAML), and then you design a dashboard. The companion app shows those dashboards well, but building a phone interface you like is real work on top of everything else.

With ESPHome the device’s behaviour is described in a YAML configuration that gets compiled. With Plynx you write the sketch yourself in C++, the way you would anyway. If you came to this hobby to write code for microcontrollers, that difference matters.

Plynx also gives you the native phone features: Home Screen widgets, a Lock Screen value, an Apple Watch app, and dashboards that keep the last known values when a board is offline. Archimedes, the assistant inside the app, can read a pin on the running board before it answers a question about it. And there is nothing to keep alive: no updates, no integration that breaks on upgrade, no host that has to be healthy for your button to work.

What each one asks of you

	Home Assistant + ESPHome	Plynx
Runs on	a host you keep on and update	your iPhone, plus a server (ours or yours)
Firmware	an ESPHome configuration, compiled per device	a sketch you write, with one small library
Phone interface	the companion app, showing dashboards you design	the app itself
Reach	almost every smart home product	boards you flash yourself
Cost	free; the optional Nabu Casa cloud is 6.50 USD a month or 65 USD a year	free

What Plynx does not do

Plynx is iPhone only, with no Android app available today. The Home Assistant companion app covers both platforms, and for a mixed household that alone decides it.

Plynx does not talk to commercial smart home gear. There is no Zigbee, Z-Wave or Matter support and no vendor integrations. It talks to boards you flash. There is nothing like the Home Assistant community either; their forums and documentation are the work of years and thousands of people.

Push notifications work only through the public Plynx server, the Apple Watch app relays through the iPhone, and automations belong to one project rather than acting as a house-wide engine.

The short version

Run both and let each do what it is shaped for. Home Assistant is the house. Plynx is the thing you are soldering this weekend, on your phone in about fifteen minutes.