From a free app to the system that keeps defibrillators ready

I’m a computer engineer and I work from Venice, Italy. I built SOS DAE myself, every part of it: the app you find on the stores, the web map in 46 languages, and the management tool for companies, gyms, schools and councils.

I don’t come from healthcare, and for this problem that isn’t a limitation: what defibrillators are missing isn’t clinical, it’s a problem of data and of seconds. Knowing where the nearest one is before you’ve finished thinking about it, and knowing that the one over there still works.

The defibrillators are out there: our dataset counts 170,253 of them worldwide, and the number grows every year. But every minute without defibrillation takes away roughly 10% of the chance of survival, and those minutes burn while someone tries to remember whether there was a cabinet in that corridor.

The public data exists — OpenStreetMap, ODbL licence — and it’s the best thing there is. But it was put there by someone who walked past once and never came back. Before writing a single line of interface, I counted what’s missing: these aren’t estimates, they’re the empty fields of all 170,253 devices, one by one.

The app is free and stays free. No account, no sign-up, no tracking: the whole dataset travels inside the phone as a 1.9 MB binary index, so it works in an underground car park, up a mountain, on a plane. Distance and direction large on the first screen, CPR guidance with a 110 bpm metronome following ERC and AHA guidelines, the emergency number of the country you’re in, 46 languages.

It’s already downloadable on the App Store, and the Android version is in review on Google Play. The only thing you pay for is the other half: the service for the people who own those defibrillators and have to keep them ready.

A defibrillator doesn’t break: it expires in pieces. The pads on one side, the battery on the other, the visual check on its own — three dates that never fall together, on an object nobody touches for months. As long as they live in a spreadsheet, the first thing to expire is the attention of the person who was meant to open it.

And the cost of getting it wrong isn’t symmetrical: a replacement ordered early costs a few tens of euros, a flat device at the moment it’s needed costs something else entirely — in lives, and in liability for whoever was supposed to check it. SOS DAE Management turns that risk into a notification, weeks in advance.

This is the part worth more than the software, and it’s why both halves of SOS DAE exist together.

Today the public map corrects itself slowly: someone who walks past a defibrillator proposes it from their own location, or reports that the cabinet is empty, and it takes three confirmations from three different devices before the correction reaches everyone. It works, it stays anonymous, and it’s error-proof — but it depends on chance: someone has to walk past, notice it, and have the app open.

Whoever is responsible for the device doesn’t depend on chance. They know the data better than anyone walking past: where it is exactly, what time you can get in, what expires when, whether it’s out for service today. It’s the same data they already keep for themselves — except that today it dies inside a file nobody opens.

The system I’m building closes that loop without asking anyone to do extra work: the log you update for your own deadlines also updates the map everyone else carries in their pocket, as much and however you decide. It isn’t charity. It’s your defibrillator being findable by someone who needs it a hundred metres away, and it’s one piece of work producing two results.

In Italy the law has required for years that defibrillators be registered, geolocated and known to the emergency dispatch centres, so that a caller is sent to the right one. It’s the right direction, and it’s also where every register meets reality: it’s only worth what its updates are worth, and no public body has the staff to go and check 170,000 cabinets. A register that updates itself, because updating it suits the person who keeps it, is the only shape that holds over time.

The first commit of SOS DAE is dated 24 July 2026: everything here has been built since then, and the pace shows. Whoever comes in now isn’t buying a finished, shrink-wrapped product — they steer the priorities of what comes next, because at this stage a request from someone using the service is worth more than any roadmap.

If you’re responsible for defibrillators, or if something you’ve read here looks wrong to you, write to me: the people who actually keep those devices are the only correction worth having.