News

GNU Taler enables digital payments at Datenspuren 2025

by Mikolai Gütschow

Following last year’s success, GNU Taler was once again successfully offered for digital payments at Datenspuren, the annual event organized by Chaos Computer Club Dresden (C3D2). Due to the lack of a public euro-based deployment, the organizers introduced SPURLOS as an event currency. This playful term is a combination of the event’s name and the German word for “voucher”, which together translate to “traceless”. Visitors could acquire SPURLOS on-site at a 1:1 exchange rate for euros from Taler cashiers, or via instant bank transfer directly into their Taler wallets. Throughout the event, SPURLOS were accepted alongside euro cash at various booths:

  • The bar served beverages like Mate, beer, and alcohol-free drinks using the Taler Point-of-Sale app.
  • The merchandise booth employed Taler OTP hardware, designed at BFH, to verify payments for t-shirts and bags without an Internet connection.
  • Food stalls, including Küfa (kitchen for all) and WOC (Waffle Operation Centre), used printed QR codes to accept variable amounts of SPURLOS in exchange for delicious food.

Privacy-preserving payments strike a chord

The offer of privacy-preserving payments with GNU Taler received an enthusiastic response. Over the course of the three-day event, our Taler deployment facilitated more than 500 payments, with 20-25% of the total transaction volume handled digitally—a remarkable 60% increase compared to last year. An estimated 100 visitors purchased SPURLOS tokens by withdrawing to Taler wallets, with pay-ins evenly distributed between cash conversions and bank transfers.

“The numbers are secondary; the real success was how much everyone enjoyed using Taler and how easy it was to use”, concluded t3sserakt, one of the organizers, during the closing session. Indeed, feedback on-site and online was overwhelmingly positive. Daniel Gultsch found it almost too boringly easy to use: “Testing GNU Taler at Datenspuren was fun. And by fun I mean mostly unspectacular. It just worked. I scanned a QR code. I got some Kolle Mate.” Thomas Fricke echoed this sentiment, calling Taler “the easiest way to pay your drinks!”

The ease of use extended to the bar staff as well. “Clicking the order and receiving payment via QR code is far simpler than managing cash change. It makes our work much easier! We should consider ways to encourage more people to use Taler next year”, shared a bartender.

Valuable insights from on-site testing

However, some attendees and staff noted that QR code generation at the bar could be slow, attributed to the Internet connection. The GNU Taler team already has ideas how to improve operation in such low-connectivity scenarios. People responsible for the merchandise stand also mentioned the offline payment confirmation using TOTP hardware could be cumbersome due to manual amount entry and verification code checks. Enhancements to streamline this process, including adding NFC support for tap-to-pay functionality, are underway.

We would like to thank the team behind Datenspuren for their collaboration and the chance to offer GNU Taler to a broader audience. Such feedback is invaluable for future improvements. If you attended the event and have thoughts to share, please reach us at contact@taler.net.

Bring Taler to your own event!

In case you know an event where you would like to offer Taler for privacy-friendly digital payments, we invite you to replicate our setup for Datenspuren: You’ll need a VM to host the regional-currency deployment along with an EBICS-enabled bank account for SEPA bank transfers (preferably at a bank tested with Taler software, as banks often have their own variations of the EBICS standard). If you’re fortunate to live in a country with a public Taler payment operator, such as Switzerland or soon Germany, the required infrastructure would mainly consist of a merchant backend tied to that payment operator. We are more than happy to assist you, so don’t hesitate to reach out with any questions!