How to Add Stablecoin Acceptance to Your Android POS Terminal
TL;DR: Any Android POS terminal (PAX, Sunmi) can accept stablecoin payments today. No new hardware. No card network. Settlement in seconds with near 0 fees. Here's how it works and what a PSP needs to integrate.
Your Terminal Already Supports Stablecoins
If your merchant network runs Android POS terminals, you're one integration away from accepting stablecoin payments.
No new hardware. No terminal swap. No firmware update.
The PAX A920 sitting on a merchant's counter right now can accept a USDC payment in 2.3 seconds at $0.04 flat. The Sunmi P2 can do the same. So can the PAX A77, Sunmi V2 Pro, or any Android or iOS terminal with NFC.
The merchant installs an app. The customer taps their phone. The stablecoin moves from the customer's wallet to the merchant's wallet. Done.
It's live on Base and Solana Mainnet today.
What "Stablecoin at POS" Actually Means
Let's be precise about what we're talking about.
Stablecoins are digital dollars (USDC), euros (EURC), or other fiat-pegged tokens that live on a blockchain. Circle issues USDC and EURC. They're regulated, audited, and backed 1:1 by reserves. A USDC is always worth $1.00. There's no price volatility.
POS terminal is the physical device where a customer pays — the thing you tap your card on. Modern terminals from PAX and Sunmi run Android, which means they can run apps just like a phone.
Stablecoin at POS means: a customer taps their phone on a merchant's Android terminal, and stablecoins move directly from the customer's wallet to the merchant's wallet. No card network. No acquirer. No clearing house. No 3-day settlement.
The merchant sees "EUR 15.00 received." Not "0.0045 ETH." Not a crypto ticker. Euros.
How the Payment Flow Works
The customer experience is identical to Apple Pay. Tap, done.
Behind the scenes:
Step 1: Tap The customer holds their phone near the terminal. NFC activates. The terminal discovers the customer's wallet and reads their address, preferred token (USDC, EURC), and chain.
Step 2: Sign The terminal sends a payment request to the phone: "Pay 15.00 EUR to merchant 0xABC..." The phone signs this request cryptographically — offline, without internet — using the customer's private key stored in the device's secure element.
This signature uses EIP-712 typed data, the same standard that MetaMask and every major Ethereum wallet uses. It's not a proprietary format. It's an open standard.
Step 3: Submit The terminal sends the signed payment to the Xeno API. The API verifies the signature, sponsors the gas fee (so the customer pays nothing extra), and executes the transfer on Base (Coinbase's Layer 2 blockchain).
Step 4: Settled The stablecoin arrives in the merchant's wallet. 2-3 seconds. Final. No chargebacks. No batch processing. No T+2.
Customer taps phone
-> Phone signs payment offline (NFC)
-> Terminal submits to API
-> API executes on-chain
-> Merchant wallet receives funds (2-3 seconds)
Compare this to a card payment:
Customer taps card
-> Terminal sends to acquirer
-> Acquirer sends to card network
-> Card network sends to issuing bank
-> Issuing bank authorises
-> Clearing happens overnight
-> Settlement in 2-3 business days
-> Merchant's bank account receives funds
What a PSP Needs to Integrate
If you're a Payment Service Provider and want to offer stablecoin acceptance to your merchants, here's what's involved.
What Xeno Provides
Relay API — Submit signed payments, check status, fetch configuration
Smart contracts — Audited forwarder contracts on Base Mainnet
Gas sponsorship — Xeno pays all blockchain gas fees
Android SDK — NFC communication module (AAR library)
Sandbox — Full testnet environment on Base Sepolia
Documentation — Protocol spec, code samples, API reference
What You Build
Terminal app — An Android app (or module in your existing POS app) that handles the NFC flow
Merchant wallets — Generate and assign wallet addresses to merchants
Reporting — Include stablecoin transactions in your merchant dashboards
Fiat conversion (optional) — If merchants want euros in their bank account, not stablecoins
Timeline
For a PSP with existing Android terminal infrastructure:
Week 1-2: Sandbox integration, NFC protocol implementation
Week 3: Testing with testnet tokens
Week 4: Production deployment, first live transaction
That's it. Four weeks from "let's try this" to live stablecoin payments on your terminal network.
The Economics
On a $100 transaction:
| Card Payment | Stablecoin Payment | |
|---|---|---|
| Merchant receives | $96.70 | $99.96 |
| Total fees | ~$3.30 (interchange + scheme + acquirer) | $0.04 flat |
| Settlement | 2-3 business days | 2-3 seconds |
| Chargeback risk | Yes ($20-100 per dispute) | Zero |
| Chargeback reserve | ~$1.00 held for 90-180 days | $0 |
For a merchant doing \(50,000/month in card payments, that's roughly \)1,650/month in card fees replaced by $20/month in stablecoin fees.
For the PSP, stablecoin payments mean:
No interchange to share with card networks
No chargeback losses or dispute management
No batch settlement or clearing infrastructure
Higher margin per transaction
Supported Terminals
Any Android terminal with NFC. Currently tested and live on:
| Manufacturer | Models |
|---|---|
| PAX | A920, A920 Pro, A920 Max, A77 |
| Sunmi | P2, V2 Pro |
| Urovo | i9100 |
| Castles Technology | SATURN1000 |
If your merchants use these terminals, they already have the hardware. If they use other Android NFC terminals, it'll work there too - it's a standard Android app.
"But My Merchants Don't Accept Crypto"
They're not accepting crypto. They're accepting dollars and euros.
USDC is a dollar. EURC is a euro. They don't fluctuate. The merchant sees "$42.50 received" — not a blockchain address, not a token name, not a price chart.
The merchant doesn't need to understand stablecoins, wallets, or blockchain. They see a payment come in, denominated in their local currency, settled instantly. It looks like a card payment that's faster and cheaper.
"Who's Using This Today?"
Stablecoin transaction volume exceeded $27.6 trillion in 2024 — more than Visa. But almost all of it is online: trading, remittances, DeFi.
The gap is physical retail. The infrastructure to spend stablecoins at a counter didn't exist until now.
Xeno is live in Iceland processing NFC stablecoin payments on merchant terminals. The tech works. The question for PSPs is whether they want to be first or fifth to offer this to their merchants.
Getting Started
If you're a PSP or acquirer interested in adding stablecoin acceptance to your terminal network, talk to us — xeno.money for production onboarding
The hardware is already on your merchants' counters. The stablecoins are already in customers' wallets. The missing piece was the protocol that connects them. That's what Xeno built.
Xeno enables instant, gasless stablecoin payments via NFC tap-to-pay. Works on existing Android POS terminals. No card network required. xeno.money
