Q11: How would the ECB ensure that digital euro payments work in the same way throughout the euro area?

The European Central Bank answers:
Supervised payment service providers (PSPs), such as euro area banks, would be responsible for distributing the digital euro. To ensure the digital euro scheme is implemented in the same way across the entire euro area, the Eurosystem is developing a digital euro scheme rule book in a collaborative and iterative process with market participants. The rulebook would establish a single set of rules, standards and procedures to ensure consistent basic digital euro services throughout the euro area, providing a uniform experience for users regardless of the Member State they are in or the PSP involved – as is the case with cash today.
We answer them:

Instead of using common terminology from engineering and computer science, and promoting well-defined specifications for protocols for the interaction of different participants in the system, the ECB uses terminology from the legal field of compliance (“rulebook”), thus indicating that the focus of the ECB lies in legal aspects of the CBDC, not the actual engineering challenges. Also, setting narrow rules, standards and procedures stands in conflict to the claim of the digital euro fostering innovation, and real customer choice. It rather promotes a financial monoculture where failures are more likely to result in wide-spread outages, similar to the recent CrowdStike outage in the Western world standardized on Microsoft technology [1].

  1. Wikipedia, 2024 CrowdStrike incident. https://en.wikipedia.org/wiki/2024_CrowdStrike_incident, 2025.