Set up a receipt printer

Before you start: An Epson TM-m30 series printer (about $200), a roll of 80mm thermal paper (one comes in the box), and the phone or tablet you run Tavvi on.

Which printer to buy

Tavvi talks to Epson receipt printers. The one to get is the Epson TM-m30III, it's the current model of the little cube you see at coffee shops everywhere. The older TM-m30II works too, so a used one is a fine way to save money.

When you're buying, check the box or listing for one thing: the connection type. The TM-m30III comes in a few versions, and the one you want supports Bluetooth or Wi-Fi, not just USB. If the listing says "Ethernet only," skip it unless your register stays parked next to a router.

New: around $200 from Epson's store, Amazon, or a POS supply shop.
Paper: it takes standard 80mm thermal rolls. A 50-pack runs about $35 and lasts a small shop months.
You do not need ink. Thermal printers burn the image into the paper, that's the whole trick.

Good to know: One printer is enough to start. If you run a kitchen and want tickets printed at the cook line, that's a second printer with its own guide, see "Set up a kitchen printer" when you're ready.

Unbox and get it ready

Drop the paper roll in with the paper feeding from underneath, toward the front. If your test page comes out blank later, the roll is in backwards, flip it.
Close the lid until it clicks, plug in power, and press the power button on the front.
Wait for the small status light to go steady. Blinking means it's still starting up.

Connect it, Bluetooth

This is the common path if your printer moves around, or there's no Wi-Fi worth trusting.

On your iPhone or iPad, open the iOS Settings app, tap Bluetooth, and wait for something like "TM-m30III" to show up. Tap it to pair.
Open Tavvi and go to Settings, then find the Printers section.
Tap to add your Receipt Printer. Tavvi scans for nearby printers, give it a few seconds.
Pick your printer from the list when it appears.
Run the test print. When you see Test print completed and paper actually comes out, you're done.

Connect it, Wi-Fi

Better for a fixed counter setup: no pairing, and anything running Tavvi on the same network can reach the printer.

Get the printer on the same Wi-Fi network as your phone or tablet. The quickest way is Epson's free "Epson TM Utility" app, it walks the printer onto your network in about two minutes.
In Tavvi, go to Settings → Printers and add your Receipt Printer. Printers on your network show up in the same list.
Pick it, test print, look for Test print completed.

Decide when receipts print

In the same Printers section, set Receipt Printer Behavior:

Always, a receipt prints after every sale, automatically. Most food spots want this.
Ask, Tavvi asks each time. Good if most customers wave the receipt away.
Never, nothing prints unless you print it yourself. Text and email receipts still work either way.

If something's off

Printer never shows up in the list. Bluetooth: confirm it's paired in iOS Settings first, Tavvi can only see printers the device already knows. Wi-Fi: confirm the printer and your device are on the same network, not one on guest Wi-Fi and one not.
It shows up, then keeps dropping. Bluetooth hates distance and metal. Keep the printer within a few meters of the register, or move it to Wi-Fi.
Test print "succeeds" but the paper is blank. The roll is in upside down. Thermal paper only prints on one side, flip the roll.
It printed a test page from Epson's utility but not from Tavvi. Something else may be holding the connection. Close the Epson app fully, power-cycle the printer, and run the Tavvi test again.