Forward
We, the Japanese students at IESE, conduct these interviews with people who embody inspiring ways of living, both as an opportunity to reflect on our own careers and as a way to share something meaningful with readers back in Japan.
For this piece, we sat down with Alex Toussaint, co-founder of Tornyol, a French hard-tech startup that was accepted into Y Combinator Fall 2025 batch. Tornyol is working on something that sounds, at first, a bit absurd: micro-drones that physically hunt and kill mosquitoes. Using smartphone microphones, ultrasonic sensors of the kind you find in car parking assist systems, and their own signal processing and control algorithms, they turn 40-gram toy drones into autonomous mosquito-killers. The ambition behind it is serious. Around 700,000 people die every year from mosquito-borne diseases like malaria, dengue, and West Nile virus, and Tornyol wants to cut the cost of mosquito control by 100x, so that eradicating mosquitoes from entire cities becomes a realistic goal.
From a Sonar-Obsessed Student to an Entrepreneur
ーCould you start by introducing yourself and telling us how you and your co-founder met?
I’m Alex, co-founder and CEO of Tornyol. I grew up in the suburbs of Paris, went through the French prep school system, and then on to an engineering school. That’s where I met Clovis and most of the people who are on our team today. We’ve known each other for about four or five years now.
ーWhy did you choose entrepreneurship in the first place?
Honestly, I didn’t want to be the guy in the cubicle next to me. I didn’t want to sit in a big company and wait ten years before having any real say in how things are done. There are just too many layers of management, and you end up depending on other people’s decisions all the time. I did a six-month internship, and by the end of it, it was very clear to me that I didn’t want to work for somebody else again. I wanted to build things my own way.
ーHow did you end up working on something as unusual as mosquito-killing drones, especially coming from France, where mosquitoes aren’t exactly a daily problem?
It’s a bit of a long story. I’ve been into sonars for a long time, since I was around 20, back in prep school. I was building phased array sonars that let you “see” the world in 3D using sound. I kept working on it alongside my studies and internships, and at some point I had a working ultrasonic sonar that could actually map the environment in 3D.
So I wanted to build a company around it, especially because I had a six-month gap coming up where I’d be completely free. The problem was, I didn’t really know what the right application was. At first I thought we could sell the sensor itself for 3D mapping, but it was pretty clear very fast that depth cameras and stereo cameras were already doing that job better on most metrics.
So we had to find a use case where our sensor was much better than the competition, not just a bit better. And that turned out to be mosquitoes. You simply can’t detect a mosquito with a stereo camera. Sonar is basically the only way to see them. A few months of research told us that, in theory, it could work. Clovis joined me six months later, and he has a strong background in optimization and reinforcement learning, which is exactly what you need for drone control.
ーThere are several accelerators in France. Why did you choose to apply to Y Combinator?
I don’t want to sound too blunt, but honestly, there’s nothing in France that really compares to Y Combinator. Even now that we’re based in France again, having YC behind us opens doors that would never have been open otherwise, not just in the US, but in France too. The network, the fundraising leverage, the credibility. We would have had a much harder time doing the same thing without going through YC.
ーThe acceptance rate is said to be less than 1%. What was the application and interview process like for you?
Yes, it’s less than 1%. They get around 15000 applications and take about 150. It’s pretty crazy when you think about it. We actually applied twice. We got rejected the first time, iterated on the product, and got in on the second try.
The process itself is pretty simple. You fill out a Google Doc, which takes about a day. Then you record a demo video and a short founder video where you just talk straight into the camera. That last part is harder than it sounds if you’ve never done it. But then you submit, and you wait.
What I find great about YC is that your application actually gets read. We were just two guys in France working on mosquito-killing drones. We didn’t come from Stanford, and we had no real network into the YC partners. But the application went through on its own merit. In our batch there were people who had dropped out of high school (they were 18), and there were much older founders too. Everyone comes in through the same open application, and someone really reads what you wrote. I’d say the hardest step is actually getting the interview in the first place. Once you’re in, it still comes down to showing strong metrics and execution, but the real bottleneck is just getting read, and YC is unusually fair about that.
ーWhat was the most valuable thing you learned from the YC partners during the batch?
YC runs on what they call office hours, which are 30-minute sessions with your partner, once every week or two. You just walk in with whatever is hurting the most right now, and they help you unblock it. There are also dinners where they invite alumni and other founders, and you can pick up a lot from those conversations.
I don’t have one specific “aha moment” to point to. It’s more that the partners teach you to go from obstacle to obstacle and just blast through them. And what you really learn is that a lot of those obstacles only exist in your own head. They’ll just say, “Why don’t you just do that?”, and it’s something you would never have done on your own before.
One concrete example: we opened pre-orders for our drones well before they were ready. We would never have done that on our own. But our partner told us, “You need to show there are customers who want this. Just open pre-orders.” So we did. A small $100 refundable reservation, easy to cancel anytime. Breaking those kinds of mental blocks is a big part of what YC does for you. And on top of that, YC puts real pressure on you. You have the $500K check, and you can’t end the batch with nothing to show. That mix of pressure and unblocking is what really pushes you forward.
ーHow has your team evolved from before YC to now?
Before YC, it was just Clovis and me. We hired our first founding engineer, Pierre, during the last month of the batch. Since the batch ended in December, we’ve been hiring pretty aggressively. Right now we’re seven: five full-time including Clovis and me, plus two interns. Two more interns are joining in early May, so we’ll be nine. Going from two to nine in less than six months is a lot for a hardware company, but we needed it.