Lefteris Karapetsas Built Rotki to Keep Your Data Private

• Lefteris Karapetsas built Rotki to protect user data through local storage and true open-source software.
• Despite low hype, Rotki gained community trust by focusing on privacy and usable tax tools.

When it comes to tax reporting and tracking crypto assets, most people probably think of cloud-based tools that store data outside their control. But Lefteris Karapetsas chose a different path. The Greek-born man built Rotki—an open-source application that stores all data locally, without the hassle of external servers, without the hassle of connecting to the cloud. He’s not chasing trends, but standing by his principles.

Lefteris is not new to the crypto world. He’s been active since the early days of Ethereum, and has been directly involved in important projects like Raiden Network and Slock.it. But the journey to Rotki wasn’t about “following the crowd.” He felt there was something missing from the ecosystem: control over one’s own data.

Rather than sneaking into conference rooms to find opportunities, Lefteris instead serves as a reminder that not all progress means giving up on the convenience of the cloud.

For him, transparency and privacy must be balanced. Imagine having to report all your household expenses to a foreign system just to find out how much your electricity bill was last month. That’s how he views most crypto software out there today.

Lefteris Karapetsas: A Builder Who Let the Code Speak for Itself

Rotki may sound idealistic to investors. But this idealism is what makes it different. Lefteris not only created a portfolio tracking tool, but also a shield against personal data exposure. On the other hand, many early adopters even thought Rotki was a personal experiment that would not grow.

However, time showed otherwise. Slowly, community support came. Several leading protocols began to open up data access so that it could be integrated into Rotki. This application is now able to present results from Aave V3 accurately—something that is not easy to do by other platforms, even paid ones.

Lefteris is also not the typical founder who appears everywhere to chase the spotlight. He prefers to discuss open-source licenses or technical details in developer forums, rather than speaking on a big stage. Sometimes his style seems stiff, but that is what makes him trusted by many people: he does not sell dreams, only products that he can build.

Furthermore, he is also active as a delegate in various governance DAOs. One of them is ENS, where he encourages governance based on open and transparent principles. Even outside of Rotki, he has invested as an angel in projects that align with his vision, like karpatkey—a DAO treasury manager.

Of course, managing an open-source product is not a smooth road. He has criticized some big projects like Uniswap for adopting licenses that he feels deviate from the true spirit of open source. He calls it “open-source washing,” an attempt to disguise the appearance of being open when it’s not.

Still Walking the Same Path Since Ethereum Devcon

What makes Lefteris’ story interesting is not just that his idealism persists, but that he has stuck to the same path since the first Ethereum Devcon. While many other developers have moved on to hype projects, he has stuck to building something that might sound “boring”—a tax tracker and a portfolio. But for some, that kind of boring stuff is exactly what’s needed most.

He doesn’t feel like he’s doing anything big. In interviews, he’s said he just wants to build a tool that anyone can use without having to give up control. But when you listen to him talk about the importance of privacy, or how users shouldn’t be fooled by UX that hides data exploitation, you can feel that this isn’t just a side project.

When you open Rotki today and see how concise your token swap reports are, or how easy it is to track your Aave earnings, it all stems from one simple idea: don’t give your data to anyone. And this simple idea, oddly enough, is increasingly rare in a crypto world full of AI and new token hype.