You may not have heard of open source developer Tony Kovanen, but the 34-year-old has collaborated on projects you know — including co-creating Next.js and co-founding ZEIT, which became Vercel, along with Guillermo Rauch and Naoyuki Kanezawa.

All told, the Finland native has had a hand in many open source projects and startups that matter to the frontend.

In a world where extroverts and influencers dominate the stage, he occasionally speaks at conference, but he is generally quiet about his work. He’s worked on projects, though, that are well-known — including Next.js, Socket.io (a real-time application framework) and Gatsby.

Finding Programming

It’s a career that almost didn’t happen. Kovanen began as a biology major at the University of Helsinki, but he wasn’t too into it. His interest was piqued, however, by bioinformatics. Someone wisely advised him to add computer science as a minor. He loved it so much, he decided to switch majors.

He was on the Ph.D. track to become an academic, when he got involved with an open source project called Sockets.io, a real-time communications library. He was two courses and a thesis shy of graduating with his masters when his involvement with Sockets.io led to a job as a JavaScript wrangler at Automattic, the company behind WordPress.

“I had some friends from said project that were working there, and I decided that the opportunity was just too good to pass up, because I could actually work on open source projects while there, and then that kind of drew me out of academia and put me on a very different path,” Kovanen said.

Creating Next.js

He spent a year and a half at Automattic before deciding it wasn’t quite what he wanted to do.

“Then my friend Guillermo was actually leaving Automattic at roughly the same time, and he wanted to do something new,” he said. “So we then ended up doing something together, which ended up being ZEIT, which today is known as Vercel.”

Before ZEIT started, though, they first wanted to build better tools for themselves. That led to the creation of Next.js.

“Just the amount of effort to set up a React application at that time, with all the best practices, was quite an endeavor, actually,” he said. “Frameworks like Next.js will help you get started and help you to do things the right way. … You don’t have to do all this work just to make your application bundled and get it out there for people to use. So that’s really where Next.js was born.”

Fun fact: In the beginning, they called the framework PHP.js, because he and Rauch both have a background in PHP and they wanted to bring the ease of just putting a PHP application out there, but with the modern stack of Node.js, JavaScript and React.

Kovanen stayed at Vercel as CTO for nearly two years, before he began to feel burnt out.

“I had to do something a little different for a while and then it didn’t make sense for me to go back anymore after taking some time for myself,” he said.

Gatsby, Eurovision and Crypto

After some time off, he joined Gatsby as one of the first employees. He worked as lead architect and engineer of infrastructure and system components, working on the platform backend for Gatsby cloud products.

Then he founded Based.io, which followed up on what ZEIT had originally planned to create: A database.

“The initial idea that we had was to make something that was like a real-time database that’s very scalable and where you can actually structure data in a way that’s more tailored for application developments,” he said.

He founded Based with Jim de Beer and then Youri Daamen. Both were living in Amsterdam, so Kovanen relocated. He spent four years before moving back to Helsinki.

“The initial idea that we had was to make something that was like a real-time database that’s very scalable and where you can actually structure data in a way that’s more tailored for application developments.” – Tony Kovanen, Developer

“Our highest profile customer always was the Eurovision Song Contest, for which we built the mobile app for some years,” he said.

In Eurovision, viewers can vote by mobile app for their favorite contestants. The database powered the process of determining who won, he added.

Based has since become more of an internal product today, he said, used by the parent company called Once.net that consults for different types of applications.

Briefly, he then worked as co-CTO at Token Terminal, which is a crypto company, although that wasn’t what enticed him. He worked on the compute infrastructure side of the company.

Then came AI.

Mastra: Working With Agentic AI Workflows

“For us developers, it’s obviously a very exciting time, because now we have all these amazing tools that we never had before, and we can slowly see how this could lead to a better productivity for us and for other things,” he said.

He joined friends Abhi Aiyer, Sam Bhagwat and Shane Thomas from Gatsby, who had started Mastra, a TypeScript AI agent framework. They were accepted into Y Combinator and wanted to grow the team. Kovanen took on the role of founding engineer.

“I felt like AI is the place where today you can really make the biggest impact, and you can really innovate the most. …I wanted to be a part of that,” he said.

Mastra offered a chance to do that.

“The way I describe it, some of the other solutions out there are more like a library that you can use to interface with an LLM, or interface with an agent. So it’s more like a React kind of thing,” he said. “Then Mastra is like the Next.js. It’s this comprehensive framework that lets you build full applications, and it gives you all of these conventions that make it nicer and easier to build and also nicer and easier to scale.”

“I like doing interesting things. I pretty much only do things I’m really passionate about, and then for me, it’s enough just to to do those things.” – Kovanen

He specifically focuses on agentic workflows, the execution engine that steers AI in the right direction.

“You’re in control of which branch of the workflow execution and what data you feed into the agent,” he explained.

This approach allows developers to build solutions with certain outcomes rather than “random” results. The agent gets fed data, then developers take the structured data back from the agent to use in some way, he said. The workflows offer developers more control, he added.

“You can create these solutions where you are more certain that you will always have a good outcome, rather than something that’s a bit random, in a sense,” he said.

Frontend developers can start quickly with Mastra because it’s all TypeScript and because it has all of the server APIs for you, he added. That means developers can create the frontend, then create their agents and immediately have all the right APIs to talk to the agent without worrying too much about the backend. It also uses libraries that frontend developers are already familiar with, such as the schema library Zod.

A Career Driven by Passion

Kovanen’s varied work makes for an extended LinkedIn profile, but for him, being a developer hasn’t been about the titles but about following his passions.

“I don’t really feel like I’m someone that likes to put myself out there that much,” he said. “I like doing interesting things. I pretty much only do things I’m really passionate about, and then for me, it’s enough just to do those things.”

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