Mini mPOS
A free, open-source point-of-sale app that runs directly on Adyen Android payment terminals. Add products,
take a payment, deliver a receipt and refund the payment on one terminal. No separate till or app subscription is needed.
The same app works on Android tablets and phones with an Adyen terminal on your network or over the internet,
or with Tap to Pay through the Adyen Payments app.
Website ·
Download APK ·
Español (México) ·
Français (France) ·
日本語 ·
Português (Brasil) ·
简体中文 ·
繁體中文
Screenshots show an English demo café using the built-in simulator, not live payments.
[!IMPORTANT]
Mini mPOS is an independent project, not made, endorsed or supported by Adyen. Test your setup in the Adyen test
environment before you take live payments.
What you can do
- Sell: products, categories, barcode scanning and custom amounts, with your own tax rates and any Adyen currency.
- Get paid: card and wallet payments, merchant-scanned wallet codes, payment links, pre-authorizations for deposits,
tips on the terminal or receipt, and charges to a shopper's saved card tokens.
- Split and mix tenders: split a bill by amount, shares or items across cards, cash, gift cards and meal vouchers;
collect the rest of a partial approval on another card.
- Deliver receipts: print on a terminal with a printer, email through your SMTP server, or share from a tablet or phone.
Add a receipt logo on the device or through the setup helper.
- Manage payments: refunds in full, by item or by amount, plus Manager-approved refunds without a receipt;
searchable history, daily totals and terminal reconciliation; token and gift card management.
- Run your setup: an admin PIN and a Manager PIN with per-action permissions, optional shopper references and card
saving, and QR transfers of products, settings and encrypted keys to additional devices.
The operations guide also covers optional workflows: audio-guided
payments, surcharges, Mexican installments, cashback and cashout, shopper-facing prompts, Adyen Giving, MOTO / Manual
Key Entry and offline processing. Availability depends on the payment destination and your Adyen configuration; test
the workflows you plan to use.
The app supports English, Simplified Chinese, Traditional Chinese, Japanese, Brazilian Portuguese, Spanish and French.
Products, settings and history stay
on each device; there is no backend, tracking or automatic synchronization between devices.
Try it or set it up
Just exploring? Install minimpos-<version>.apk from the
latest release on an Android phone (Android 9+) or emulator.
Away from an Adyen terminal, the default is the simulator: no account, keys or real card needed. Choose outcomes and
printer behavior in Settings › Simulator.
Ready to connect to Adyen? Follow Quick start.
It covers device, network and credential prerequisites, deployment and all four payment setups. Every real-payment
setup needs the Checkout API; the setup helper lets you enter keys
on a computer and scan them in.
| Guide | What it covers |
|---|
| Quick start | Check prerequisites, install, connect, test and go live. |
| Using Mini mPOS | Daily operations: sell, refund, receipts, closing the day, optional checkout workflows and more devices. |
| Troubleshooting | Unknown results, declines, pairing, network, capture, printer and email problems. |
Important boundaries
Mini mPOS has no server to receive Adyen webhooks. Refunds and captures shown as requested need final confirmation
in the Customer Area. Paid payment links are refunded there, not in the app. If a payment's result is unknown, check it
before charging again.
Mini mPOS saves API keys encrypted on the device. This is a trade-off against the Adyen recommendation to keep
keys on a server. Use narrowly scoped credentials, protect the device, and review SECURITY.md.
For contributors
The app is Kotlin with Jetpack Compose, built with Gradle. With JDK 17+ and the Android SDK installed, build and
install a debug copy on an Android 9+ device or emulator, then run the full verification gate:
./gradlew :app:installDebug
./gradlew qualityGate
See CONTRIBUTING.md for prerequisites, testing, architecture and releases—including signing your
own APK. Coding agents start at AGENTS.md. Use CONTEXT.md for domain terminology. Report
vulnerabilities privately through
the security policy, not a public issue.
License
MIT © 2026 Adam Stiskala. Adyen is a trademark of Adyen N.V.
