INTERVIEW: peek behind EU vaccine passport's IT curtain
However, ten weeks later, they are set to unveil the region's first online "vaccine passport," with the ambitious goal of making European summer travel easier.
"There's a feeling of relief, and also pride that we managed to do it," said Lieven from T-Systems, who jointly led the IT project with fellow German firm SAP.
Both firms have been challenged by the European Commission to provide a digital certificate that verifies whether a person has been properly vaccinated against Covid-19, has tested negative, or has recovered from a coronavirus infection.
The data is saved in a QR code that may be scanned and recognized by the European Union's 27 countries, as well as Iceland, Norway, and Liechtenstein.
The "vaccine passport" application is the first digital health portal to be allowed across EU borders while adhering to the bloc's strict data privacy standards.
"Even if it was challenging, we've come up with a solution in Europe that many other, even hi-tech regions and countries don't have yet," Lieven told AFP in a phone interview.
Last year, T-Systems, a subsidiary of Deutsche Telekom, and SAP, a software company, developed Germany's privacy-conscious contact-tracing app.
They were eventually hired by Brussels to connect multiple national virus-tracing software so that the epidemic could be tracked more effectively across borders.
The software for the new digital health pass was "similar," but "much more complex," according to Lieven, because more countries had a say from the start.
Of course, time was of importance, with governments keen to make travel and tourism as normal as possible beginning July 1, the start of Europe's critical summer vacation season.
Lieven and his engineers started coding for the prototype before they even got the full specifications, using the same teams who worked on the prior corona apps.
On May 20, the European Parliament and EU member states established a political agreement on the certificate, although there was always the possibility that countries would seek surprise revisions until then.
Lieven explained that writing the program was only one aspect of the process, with data protection, safety concerns, and extensive international collaboration all requiring consideration.
One of the most "exciting" occasions, according to Lieven, was the weekly video chat, which brought together 130 representatives from participating countries to share updates and discuss issues.
The most difficult three weeks were spent methodically testing the interconnection between each country's national system and European servers.
The critical testing phase was supposed to begin on the first day, but the two countries that were supposed to launch it were not ready.
"So that Monday, we had no one we could test with. That was a surprise," Lieven recalled.
But the kinks were resolved by the next day and "everything worked like a charm".
Lieven is now eager to put the app to good use for himself.
During a recent trip to see his son in Denmark, Lieven told him that "the next time you visit, your trip will be easier with the digital certificate".
COVER IMAGE VIA MEDICAL DEVICE NETWORK