At just 25 years old, Guillaume Rozier is devising the most popular tools to emerge during France's Covid-19 pandemic -- the data websites charting the costs of the crisis, and the progress in the fight to end it.
"I would never have imagined all the innovations, the creativity, that have their source in these data," Rozier told AFP.
His Covidtracker.fr site and its siblings, now maintained with the help of an army of volunteers, have become essential reading earning the praise of President Emmanuel Macron.
A lawmaker in his centrist party, Francois Jolivet, on Monday urged Health Minister Olivier Veran to present Rozier with the Legion of Honour, France's highest civil distinction.
Rozier got the idea to start putting France's Covid numbers in context in March 2020, while finishing his engineering studies at the Telecom Nancy university in eastern France.
He was focusing in particular on artificial intelligence and the exploitation of Big Data, just as French officials were anxiously watching as coronavirus cases began to overwhelm neighbouring Italy.
To see if French cases were poised to soar as well, Rozier sought out mortality rates and Covid infection numbers compiled by Johns Hopkins university in the United States.
A graph comparing the two rates was unequivocal -- despite a lag of a few weeks, France was going to face the same struggle as Italy.
- Big Data believer -
Rozier shared his discoveries with friends and relatives, who began clamouring for daily updates as the pandemic worsened and France went into its first lockdown on March 17.
So he created a website with charts that updated automatically and posted the link on Twitter, where demand for the virus data went viral.
Baptised Covidtracker, it quickly became a go-to source for the grim tolls on deaths and hospitalisations.
"It had 10 million unique visitors in April 2021," Rozier said.
When France began its inoculation drive in January, he added Vaccinetracker, which soon made it clear that the campaign was getting off to a slow start compared with some European neighbours.
But securing official health ministry data wasn't easy -- Rozier warned he would shut down the vaccines site unless the data was made freely available, which officials eventually did.
"All data produced by an administration should be published quickly and thoroughly, and in a format that renders it easily accessible for automation," he insisted.
As more people became eligible for getting a jab, Rozier rolled out Vitemadose, a one-stop solution for finding vaccine appointments via several reservation platforms including Doctolib.
His latest creation goes live Wednesday, when Chronodose will let any adult search for unfilled vaccination appointments. That comes just a week after Macron announced these would be open to any adult regardless of age or health condition in a bid to ensure no doses go to waste.
"Every day there are still several thousands of vaccination slots still available for the same day or the next," Rozier said.
"You can imagine everything that data access could see develop, in health care but also the economy, transports, global warming or energy," he added.
But while keeping on with Covidtracker, Rozier now has a day job -- working for an IT consulting firm that is part of the US giant Accenture.