dExPay

Inspiration

This easy going Carribien bar in Copenhagen already uses QR codes for the frequently changing menu. Why not improve this with an ordering process to finish payment while the bartender completes your order.

What it does

It demonstrates how payment with Bitcoin can be achieved through the Lightning network with the Lightspark SDK. The webapp integrates with Shopbox and uses the Lightning scheme "lightning://" to launch the user's existing wallet app.

How we built it

For the mobile POS, Flutter was used in combination with the Flutter Lightspark Connect SDK. It was all based on the excellent POS app, Shopbox.com, which provides an API to make it all possible.

Vercel made it easy to deploy.

Challenges we ran into

As our Lightspark account is not yet approved for production, it was challenging to completely test the whole process with existing wallet apps.

Luckily, sample invoices was available for demonstration. It however resulted in quite a tab of 2,000,000 SATS(~$1250).

Accomplishments that we're proud of

With the integration with an existing POS, it was easy to demonstrate the idea to a well known bar in Copenhagen. By being able to answer, how this will integrate with their existing POS and without having to buy new specialized hardware. The bartender was immediately open to try it out.

What we learned

Everybody knows about Bitcoins but no one knows how to use them. By creating a payment process very similar already existing payments like MobilePay, it stopped being mysterious and scary. Next step is to teach everybody about SATS(Satoshis) as no one will realistically be paying in full coins.

What's next for dExPay

Finish integration with Lightspark for the Mobile POS app, so the bartender can initiate orders at the guest's table and accept Lightning payments immediately.

Further explore having QR codes at each table to allow guests. Extend the MobilePos app with order status. Add an follow-up process to add Tips for the excellent drinks and service.

iPads are a popular device for modern POS systems. However Android devices works even better as they allow NFC integration and sometimes built-in receipt printers. Next step will be to further optimize for these dedicated Android POS devices. With built-in receipt printers, this can be taken into festivals and events.

Built With

• flutter
• javascript
• lightning
• lightspark
• node.js
• typescript