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Anastasios Angelopoulos
Co-Founder & CEO, Arena

The AI Leaderboard Every Top Lab Watches - Inside LMArena's Real-World AI Battleground

📅 Jan 07, 2026 1st10 Podcast 42 MIN 337 VIEWS 97 SEGMENTS · 2 SPEAKERS
What happens when three PhD students accidentally build the infrastructure that every major AI lab depends on? OR What if the AI benchmarks everyone trusts are measuring the wrong thing entirely? On this episode of the *1st10 Podcast*, host Boris Epstein sits down with Anastasios Angelopoulos, co-founder and CEO of LMArena, to unpack LMArena went from a Berkeley side project built with free pizza and zero revenue to a $100M company with 42 employees and tens of millions of users in under two years. Tune in to hear them talk about: How Academic AI benchmarks measure the wrong things and real-...

Questions asked in this interview

12
  1. 2:23Who do you root for when Stanford is playing Berkeley?
  2. 2:51It's like the big game, right?
  3. 4:12But maybe I'll ask, if you had to pick your favorite record or favorite album, what would it be?
  4. 8:36And then Chatbot Arena came around as a side project. What happened?
  5. 13:05So what was the vision that these resources were very important for?
  6. 14:11And so is that what you're saying?
  7. 19:22Is that how you envision that?
  8. 23:36Are we early? Are we late?
  9. 24:44It feels like everything is moving at warp speed and it feels like there's chatter about are we in a bubble? Have we overgrown?
  10. 28:28So is this your first company and what was it like kind of just saying, yeah, I'm doing this, like maybe the fear versus excitement kind of mindset around it?
  11. 34:30What type of person does really well at LMArena?
  12. 39:26Where should they focus their energies?
Anastasios Angelopoulos 0:00 ↗
I never did any of this because I wanted to have commercial anything. We're at Berkeley, you know, we're eating pizza, free pizza, making no money, you know, but Sam Altman cares what we're doing. Our goal has always been to be stewards of the ecosystem, to have as much positive impact as we can. We're academics by nature and we found ourselves serendipitously at the center of it. Well, the vision has always been to measure and advance the frontier of AI for real world usage as opposed to some, you know, academic benchmark that somebody has, you know, collected perhaps painstakingly, but that doesn't necessarily reflect real users. Who cares how well it does on a math olympiad? I do mathematics in my work and even I don't care about it because it doesn't reflect the type of math that I do.
Boris 0:51 ↗
On today's episode of the First 10 podcast, we are honored to host a true powerhouse who is literally defining how the AI industry measures success: Anastasios Angelopoulos. Anastasios is a graduate of Stanford and earned his PhD from UC Berkeley, which also happens to be where he began his journey as an entrepreneur. Anastasios is the co-founder and CEO of LMArena, the company that spun out of the hugely influential Chatbot Arena project, which he helped launch right out of the Sky Computing Lab at Berkeley. Chatbot Arena rapidly grew to over a million monthly users and quickly became the de facto standard used by every major AI lab from Google to Anthropic to test their models, sometimes even pre-release. LMArena recently secured 100 million in seed funding and is building the indispensable infrastructure required for reliable AI. Our conversation today will revolve around how LMArena hopes to lead the AI industry forward and the engineering and hiring challenges they expect to encounter in that process. Anastasios, welcome to the First 10 podcast.
Anastasios Angelopoulos 1:58 ↗
Thanks for having me, Boris, and excited to be here. Honored to be your guest on the podcast. First 10 has been a wonderful partner to us at LMArena too.
Boris 2:06 ↗
Thank you. We are going to absolutely quote that. So thank you for saying that, Anastasios. It's been a pleasure working with you as well. I'm excited to catch up and I'm excited to, you know, hear more of your story.
Anastasios Angelopoulos 2:18 ↗
Great. Yeah.
Boris 2:20 ↗
I have a very important question for you.
Anastasios Angelopoulos 2:22 ↗
Please.
Boris 2:23 ↗
Who do you root for when Stanford is playing Berkeley?
Anastasios Angelopoulos 2:27 ↗
I root for whatever school I'm at. So, and what ended up happening is that all the years that I was at Stanford, Stanford won. And then all the years that I was at Berkeley, Berkeley won.
Boris 2:36 ↗
Wow. That has to be some like freaky, that's kind of some freaky stat stuff.
Anastasios Angelopoulos 2:41 ↗
Yeah. I don't know. I mean, yeah. You'll have to ask the players because I never saw any of the games.
Boris 2:47 ↗
Amazing. We got to get you to a game.
Anastasios Angelopoulos 2:51 ↗
Yeah.
Boris 2:51 ↗
It's like the big game, right?
Anastasios Angelopoulos 2:54 ↗
I've been busy doing statistics instead of football. That's the problem.
Boris 2:58 ↗
The world appreciates that. Any hidden talents that you would like to share with the world? Anastasios, do you have any hidden talents?
Anastasios Angelopoulos 3:06 ↗
I don't know how hidden, I don't hide much. I kind of wear my heart on my sleeve, but I guess outside of the work, you know, outside of professional work, the main thing that I do is music. So, I have a little music studio at home. I play guitar, piano, I sing, I play bass. I mean, bass and guitar are kind of the same thing anyway because it's electric bass. Yeah. And yeah, I just hang out, play music with my friends, produce. It was my first love. I thought I was going to go to college and major in music. I ended up majoring in like electrical engineering because of signal processing, which had this connection to music because you do a lot of signal processing when you produce songs. And I'd say that's maybe a little known talent to the rest of the world. Not clear that it's a talent really. I'm obviously not a professional, but I do love doing it.
Boris 4:03 ↗
Maybe a gift. I mean, and you're right, it is out in the world. I thought I may have seen video, but I wasn't positive it was you.
Anastasios Angelopoulos 4:11 ↗
That's funny.
Boris 4:12 ↗
I put, you know, of the very little decor that I have in my studio here, I do like to put up a record in honor of our guest. So I put up a Tony Bennett record for you guys. But maybe I'll ask, if you had to pick your favorite record or favorite album, what would it be?
Anastasios Angelopoulos 4:34 ↗
Maybe Voodoo by D'Angelo.
Boris 4:37 ↗
Okay.
Anastasios Angelopoulos 4:37 ↗
Yeah. One of my favorite songs is Really Love by D'Angelo. So I'd say I don't remember if that's on Voodoo or Black Messiah. Maybe Black Messiah.
Boris 4:49 ↗
He's incredible.
Anastasios Angelopoulos 4:49 ↗
Yeah, he's awesome.
Boris 4:51 ↗
Singer. Yeah. Okay. I'll look into that. I always look to expand my collection.
Anastasios Angelopoulos 4:56 ↗
Yeah. Do it. He recently passed away, right?
Boris 5:01 ↗
It is possible.
Anastasios Angelopoulos 5:03 ↗
Yeah, I think he died. He died this year. Yeah, he died a couple months ago. Super sad, at 50, 51.
Boris 5:08 ↗
Oh, okay. I'll definitely have to look into that record. Rest in peace, D'Angelo.
Anastasios Angelopoulos 5:13 ↗
Yeah, rest in peace, D'Angelo.
Boris 5:15 ↗
Rest in peace, D'Angelo. Let's dedicate the rest of this episode to, you know, may his soul only continue to elevate. Okay. So curious about where it all started, right? So you studied computer science and then machine learning. Maybe orient us, when was that in relation to the ChatGPT moment, which I like to talk a lot about on this show? Was AI a thing? Were you thinking about AI when you were...
Anastasios Angelopoulos 5:40 ↗
No, you know, I never did any of this because I wanted to have commercial anything. I had done my undergraduate in EE. I was working primarily on medicine, like medical devices, trying to help, you know, disabled people and people with diseases of the eye primarily, like, you know, people that are going blind, try to help them walk and, you know, use devices better. And after I finished my undergrad, I felt like I didn't have enough foundational, fundamental understanding to be able to engage with science for my whole life. And so to acquire some of that extra knowledge and expertise, I decided to do a PhD. It was really only about knowledge acquisition and, you know, to sort of train my thinking muscle.
Boris 6:36 ↗
Okay.
Anastasios Angelopoulos 6:37 ↗
But I decided to do a PhD in something fundamental, and also because I thought maybe I'll do a master's, but that seems expensive. So a PhD, I'll be able to maybe get it for free. And if I don't like it, I'll just drop out with the master's. So I applied to PhD programs. I had a few mentors at the time in Stanford like Joseph Kahn, Stephen Boyd, people like that, Gordon Wetzstein, who really, really encouraged me. And so then I ended up going and doing a PhD at Berkeley under Mike Jordan and Jen Malik, who were two huge luminaries in the AI field. It was before, again, any of this like big commercial stuff. I started my PhD in 2019, I think.
Boris 7:20 ↗
Okay.
Anastasios Angelopoulos 7:20 ↗
So it's before any of the ChatGPT generative AI boom. I guess at that time it was all about self-driving. But it was orders of magnitude smaller in terms of the compensation that you could receive with the skill set that you get with an AI PhD. And the work that I concentrated on was all about reliability. It was about developing the mathematical and statistical foundations of reliable AI. And I started by working on this field called conformal prediction. Conformal prediction is a methodology for placing uncertainty bounds on black-box algorithms. One of the most important applications being to AI, helping know when AI is wrong and use it therefore with confidence. And that's what I spent the majority of my PhD on, as well as synthetic data, trying to understand how to properly leverage synthetic data to draw valid scientific conclusions. And again, without even a thought of turning it into a company or anything.
Boris 8:36 ↗
And then Chatbot Arena came around as a side project. What happened? You guys were working on that while at Berkeley.
Anastasios Angelopoulos 8:44 ↗
While at Berkeley, yeah. Well, what happened was that I got introduced to Wei through my advisor Mike, and they were kind of working on this pairwise preference thing, and it was very, very early stages at the time, and needed to know how to do proper statistical inference on the data that they were gathering through this platform, how to construct the leaderboard, how to construct confidence intervals for the leaderboard, you know, what methodology to be using, and I helped shape that. It wasn't really anybody's main thing except for maybe Wei's at the time. And then we wrote a paper on it, and I think we kind of thought that would be that, like we would continue to run the platform, try to have an impact with it, but we never expected it to be a company. And then it just grew and grew and grew up until the point that even while we were students, GPT-4o, for example, released on our platform before it got into ChatGPT. The same thing happened with a bunch of the Gemini models, and, you know, at that time it was like an explosion of diversity in the AI ecosystem around models. So many new models, so much competition as to who was going to be the best. And we found ourselves serendipitously at the center of it because we had built this competitive platform. And then it became latched onto by media, by labs, by researchers as a battleground for these new and really exciting corporate competitive markets to duke it out. And we were like, 'Wow, we're at Berkeley, you know, we're eating pizza, free pizza, going to seminars, eating free pizza.' And making no money, you know, but like Sam Altman cares what we're doing.
Boris 10:57 ↗
That's so cool. And this thing had millions of users.
Anastasios Angelopoulos 11:02 ↗
Wow.
Boris 11:03 ↗
While we were still in school.
Anastasios Angelopoulos 11:06 ↗
And not only did they come, but they stayed. Like the attention only grew and grew on the platform over time. And it started becoming this really central gold standard benchmark for measuring the real world utility of AI to real users.
Boris 11:28 ↗
Yeah.
Anastasios Angelopoulos 11:28 ↗
Which is something that we really believed in. And so eventually Wei and I, we kind of got together and said we want to turn this into a company and we want to do it together.
Boris 11:40 ↗
I was going to ask about what prompted you to turn it into a commercial. So you were building it as a side project and then it just started to get this crazy traction, including from all these luminary companies and startups out there. And you're like, what was the moment where you're like, should this or shouldn't this be a company? And yeah, tell me more.
Anastasios Angelopoulos 12:04 ↗
There was no moment. It took a long time for us to think about what to do with the project because our goal was never really to make money. Our goal has always been to be stewards of the ecosystem, to have as much positive impact as we can. We're academics by nature. You know, we don't care about aggrandizing or enriching ourselves. And so we thought about, hey, what's the right way to do it? Should we do it as a nonprofit? Should we do it as a company? Should we just donate the whole thing to somebody? And what ended up happening is that it became clear that the only way to make it work was to have the scale and resources that a company could provide, and that there was a business model that would allow this to scale to become a really central piece of the ecosystem.
Boris 13:05 ↗
And what was the vision for it? So initially it was a project to help the industry with reliability, and then you talked about it being important to have the resources to grow into a company to achieve its vision. So what was the vision that these resources were very important for?

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APA

Angelopoulos, A. (2026, January 7). The AI Leaderboard Every Top Lab Watches - Inside LMArena's Real-World AI Battleground [Interview transcript]. 1st10 Podcast. CEOInterviews.AI. https://ceointerviews.ai/interview/3026881/

MLA

Anastasios Angelopoulos. "The AI Leaderboard Every Top Lab Watches - Inside LMArena's Real-World AI Battleground." 1st10 Podcast, 7 Jan. 2026. Transcript, CEOInterviews.AI, https://ceointerviews.ai/interview/3026881/.

BibTeX
@misc{angelopoulos2026_3026881,
  author       = {Anastasios Angelopoulos},
  title        = {The AI Leaderboard Every Top Lab Watches - Inside LMArena's Real-World AI Battleground},
  howpublished = {Interview transcript, 1st10 Podcast. CEOInterviews.AI},
  year         = {2026},
  month        = {jan},
  url          = {https://ceointerviews.ai/interview/3026881/},
  note         = {Speaker-attributed transcript with timestamps}
}