LMArena and The Future of AI Reliability

LMArena and The Future of AI Reliability

About a month ago, we announced that LMArena was becoming a company to better support our growing community platform. As we take this next step, we're staying true to our original mission of rigorous, neutral, and community-driven evaluations.

Today, we’re excited to share that we’ve raised $100M in seed funding to continue advancing that mission, and to keep improving the platform for everyone who uses it. As new AI modalities emerge and become more integrated into our daily lives with chatbots, code assistants, image generators and even video editors, human preference will remain a core metric to AI progress. 

Becoming a company isn’t just about receiving funding, it’s also about building something sustainable. For us, that means a business model rooted in trust. LMArena is a place where community involvement, transparent methodology, and scientific accuracy aren’t nice-to-haves, but non-negotiables. Evaluation with our community is a scientific process informed by diverse human judgment. Diversity is key so we are making a commitment to our community: LMArena will stay open and accessible to everyone. To do that sustainably, we’re focused on creating long-term value through services that benefit the entire AI ecosystem and serve the larger community. 

At our core, LMArena will always provide:

  • An open, accessible platform for the community to participate in evaluating and comparing models through real-world prompts.
  • Transparent, science-driven leaderboard policies that ensure every model is tested fairly, consistently, and with community input.
  • Features designed for the community, from a better UI/UX to more ways to engage, vote, and contribute to AI progress.
  • Research to push the cutting edge of AI evaluation and reliability.

We will also support model providers and developers by:

  • Offering high-quality, real-world feedback from a diverse global user base to help them improve their models.
  • Creating tools and dashboards that simplify evaluation, track performance over time, and uncover strengths and weaknesses.
  • Maintaining a neutral, trustworthy platform without exclusivity. 

Our guiding principle is simple: commercial sustainability should never come at the cost of community trust or great science. We’re building a business model that aligns incentives across community members, researchers, and providers to make sure the ecosystem is benefiting from more open, and better AI.

Why Our Investors Believe in LMArena

The seed round was led by a16z and UC Investments (University of California) with participation from Lightspeed, Laude Ventures, Felicis, Kleiner Perkins, The House Fund, and others. 

We’ve been fortunate to bring on backers who share our deep commitment to open science and building long-term trust in AI. Anjney Midha, General Partner from a16z shared: “We invested in LMArena because the future of AI is about reliability and it needs rigorous, innovative, transparent evaluation to get there. We believe no one is better positioned to lead that than the LMArena community.” Jagdeep Singh Bachher, chief investment officer at UC Investments, added, “We’re excited to see open AI research translated into real-world impact through platforms like LMArena. Supporting innovation from university labs such as those at UC Berkeley is essential for building technologies that responsibly serve the public and advance the field.”

Our mission, the team, and the community behind it, are also key reasons why our partners chose to invest. Bucky Moore, Partner from Lightspeed shared, “Arena is building one of the most valuable data assets in AI: a real-time, community-driven record of how models perform in the wild. This ground-level signal has quickly become an indispensable ingredient to how frontier labs improve their products. Lightspeed is thrilled to partner with Anastasios, Wei-Lin, and Ion to bring these capabilities to the industry en masse and maximize AI’s positive impact on society.”

“We didn’t invest in just a platform - we invested in a team building the infrastructure critical to AI progress,” said Andy Konwinski, co-founder and GP of Laude Ventures. “Their approach to model evaluation is unique, transparent, and has become a de facto standard. In a field moving this fast - and with such enormous consequence - it’s the kind of work that will shape how our field advances and holds itself accountable.” 

Ion Stoica, co-founder and UC Berkeley professor put it this way: “AI evaluation has often lagged behind model development. LMArena closes that gap by putting robust, community-driven science at the center. It's refreshing to be part of a team committed to approaching AI reliability with long-term integrity in a space moving this fast.” This level of investor support reflects not just belief in the product, but in our larger objective: to make AI evaluation rigorous, reproducible, and shaped by community.

Welcome to The New LMArena!

Alongside this funding announcement, we’re excited to relaunch LMArena with a whole new UI! Our community’s feedback is the foundation of today’s launch and everything that follows. The backing will help us accelerate even further, but the heart of it all remains the same. LMArena will always be a neutral, open, community-driven space for evaluating and improving AI reliability. That’s not just our strategy, it’s our conviction, built on scientific rigor, fairness, and transparency in AI evaluation. Another reason why we chose to move forward with long-term partners who support the mission, as much as the science behind it all. 

We started as a research project under UC Berkeley / LMSys. Then we became Chatbot Arena, publishing our first leaderboard fueled by community-driven model evaluation. Today, we officially begin our new chapter as LMArena, with a whole new look and a broader community-driven platform spanning multiple modalities, shaped by how people actually use AI. This shift reflects a deeper commitment to understanding not just which models perform best, but for whom, in what context, and why that matters. 

The original Chatbot Arena project was born from the research community, and scientific curiosity still drives everything we do. We believe better evaluations lead to better models. Better models mean more reliable AI for everyone. Over the past few months, we’ve been rebuilding from the ground up, directly with our community. From the early Alpha invite in our Discord server to the open Beta, thousands of you have tested the limits, shared detailed feedback, and helped us shape the platform into what it is today. Thank you! Here’s a quick look at what the community accomplished during Alpha & Beta: 

  • Over 40,000 votes cast during Beta
  • Over 1,000 polish and feature suggestions reviewed
  • 40+ bugs reported and fixed

Today, this community-built, battle-tested version becomes the official LMArena at lmarena.ai.

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It brings big improvements across the board:

  • Better performance and reduced error rates
  • A more intuitive layout and cleaner voting experience
  • Mobile optimization and smoother conversation flow
  • More transparency around what’s happening behind the scenes

Advancing the Science of Human Preference

Beyond the LMArena user experience, we believe that advancing the science of human preference evaluation is just as important as advancing the models themselves. That’s why we publish our evaluation methods, model sampling rules, and platform metrics. If we want trustworthy AI, the evaluations themselves must be trustworthy too. Our company will continue to support fundamental research and development in this area. We welcome the larger research community to come together with us to uphold evaluation integrity. 

Features on LMArena like “Style Control” demonstrate the difference in human preference when the style and formatting of a model’s response is filtered. Prompt-to-Leaderboard (P2L) is another example, which generates a customized leaderboard of AI models specific to a prompt. Both are just the beginning of understanding the diversity of human preference. We’re actively working on more, but we’re not here just to build features. We want to lay the groundwork for human preference evaluation methods that are reproducible, robust, and truly reflective of how AI is used in the real world.

Future Plans for LMArena

This launch and funding news marks a huge milestone, but LMArena is still very much a work in progress. We’re continuing to ship improvements from faster interfaces to better sampling methods, all grounded in our belief that great science requires open data, reproducible methods, and direct feedback from our community. Some features from the legacy site, like advanced model settings aren’t live yet, but they’re on the way.

Because of this, the legacy site will still be available at legacy.lmarena.ai while we continue to evolve and bring more features to parity. Going forward, all updates and improvements will be happening on the new LMArena, and we’re excited to keep building it with your input.

We’ll keep building in the open, because it’s the community that will help shape what comes next. If something feels off, confusing, or just missing, let us know. Every vote, comment, and bug report brings us one step closer to the platform you’ve asked for. Here are a few things you’ve already requested that are on the way:

  • More Modalities
  • Data Explorer 
  • User Login

The future of LMArena is about making the platform faster and easier to access for everyone. We’re especially excited to see if these foundational UI improvements help bring in more people from around the world, because the more diverse the voices, the more valuable the signal we generate for AI progress. Every perspective helps move the ecosystem forward, not just by ranking models, but by revealing how each model succeeds or fails in real-world use. When more people participate, our evaluations become not only more representative, but more powerful for shaping the future of AI.

We’re grateful to our community, and to our backers, for believing in a future where AI evaluation is open, community-led, and based in rigorous, transparent science. This launch isn’t the finish line, it’s the next step in making AI more reliable for everyone.

We’d love to hear what you think!

Try the new LMArena → https://lmarena.ai
Join the conversation → Discord
Join the team → Openings
Follow us → X/Twitter