The person behind Helios

Jérôme CREMOUX

Self-taught, for the love of it.

The self-taught way

From a store repair counter to the space industry.

I'm Jérôme CREMOUX, 44, a French developer. Unlike many in this field, I hold no degree: no engineering school, no university. I fell in love with code as a kid, and I've never stopped since. Everything I know comes from open source, from personal projects, and from years of learning on the job: building, taking old devices apart to understand how they work, figuring out how to make them work differently, and learning from other people's code.

You could say my path hasn't been a straight line. I spent five years behind the service counter of a store, fixing customers' computers and coding at night out of passion, until a short career change finally let me make it my job. Then six years at a small software company, where I went from developer to lead developer on mobile, web and backend. A stint as a consultant, and today I'm the technical lead on a 3D visualization software for the space industry. From a store repair counter to the space industry, self-taught: even today, I still can hardly believe it.

I love creating. What keeps me going is curiosity, and it refuses to stay in a single field. UX and graphic design matter to me as much as code. I model in 3D. I love software architecture and things that are clean, square, well made. Most of all, I can't let go of a problem until I've answered the two questions that count: why, and how.

Open source is what shaped me as a developer, so working for it today is my way of giving back what I received. But it's more than gratitude: I believe open source is the last independent space we have left, the only real counterweight to the handful of giant platforms that decide what our digital lives look like. I want my work to strengthen that space, not feed the other one.

That's what Helios and Helios Forecast mean to me: my contribution. Free tools, built in full transparency, that help everyone see and understand their energy. To me, technology shouldn't lock people in: it should hand them back control. And if I can spend the rest of my career on this side of the fence, trying to leave the world a little better than I found it, I'll consider it time well spent.

Support the project

Helios is free. A coffee keeps it alive.

Helios and Helios Forecast are free and open source, built in my spare time, which often spills over into the night. If they're useful to you, a coffee is the nicest way to say thanks, and it's very concretely what lets me keep going.

Why I built it

We can still turn this around.

I'm Jérôme, 44, the developer behind Helios. After years spent across the whole stack, backend, frontend, 3D, games, embedded, I wanted to build something that truly matters to me.

A card won't save the planet, I know. But guilt and numbers nobody reads change no one: we change when we can finally see what's happening in our own home. That's the whole point of Helios: make energy visible, tangible, even beautiful, so that acting stops being a chore and becomes the obvious thing to do.

Helios is free and open source, built by a single person, in full transparency.

ReikanYsora - Jérôme CREMOUX - 2026