Braintrust's series B: building the infrastructure for production AI
Braintrust has raised $80M to become the observability layer for production AI.
Our Series B is led by ICONIQ, and I'm also happy to welcome back prior investors Andreessen Horowitz, Greylock, Elad Gil, basecase capital, and others, who joined us again for this round.
Like many founders, I started Braintrust to solve a problem I experienced in my own work. At both Impira and Figma, I had to go through the difficult process of building internal tools for evals. I realized that if I had to deal with this issue twice, it was probably true for others as well, so I started talking to friends and peers to understand what they needed from evals and AI observability. This focus on real users and their needs has stayed with me, and is at the heart of how we build Braintrust.
Since founding Braintrust, AI has rapidly moved from experimentation to production. Agents are no longer demos or side projects, but are embedded in nearly every engineering workflow. Models from frontier labs and open-source upstarts power products we use every day. Non-technical teammates are vibe-coding apps in their spare time, while both large companies and scrappy startups build AI into products that simply need to work, without exception.
Despite this criticality, teams have never had less conviction about what will fail next. When something does break, it's never been harder to explain why. Traces are now long-running, multi-step agents with tool calls and intermediate reasoning that capture massive volumes of data unfolding over time, often hundreds of megabytes per interaction. Traditional observability can no longer keep pace with this scale, and teams are straining to juggle the demands of the business with the limitations of existing tools. We experienced this ourselves at Braintrust, and even built our own database to manage the complexity that AI observability entails.
As our customers bring AI into production at scale in 2026, it's time to treat observability like a core piece of infrastructure. AI is an operating system that changes constantly, beyond what humans can inspect directly, and engineering and product teams need to maintain clarity, accountability, and confidence in every update.
AI is a critical part of our customers' products, and these products in turn support the world's largest companies. This is why Notion, Replit, Cloudflare, Ramp, and Dropbox are using Braintrust. Customers guide what we do at Braintrust. I make sure to talk to them every day, listening to their difficulties and celebrating their wins. If Braintrust makes their lives easier and their products better, I know we are doing our job.
This customer focus is shared by Matt Jacobson, General Partner at ICONIQ. In all our conversations over the past few months, he's returned repeatedly to the question of what our customers are doing and how we can help them. He's worked with many companies that share our growth trajectory, and he knows that these companies succeed when their customers succeed. It's a privilege to have him on our team, and I can't wait to work with him as we grow.
At ICONIQ, we have seen that a defining trait among the generational companies is deep, authentic customer obsession. We believe Ankur and the Braintrust team embody this mindset and have been building their product from the start to serve the evolving needs of their customers. The incredible validation we have seen firsthand from leading AI teams using Braintrust is a testament to the depth of their commitment.
— Matt Jacobson, ICONIQ
With this new funding, we're building our engineering and GTM teams, expanding our footprint to new offices, and working on new products that you'll hear more about at our user conference, Trace, next week. But one crucial thing won't be changing: our focus on our customers.
This week, we mailed notes to customers sharing this news directly and thanking them for getting us to this point. This is just one of many milestones for Braintrust, and I hope to send more of these notes as our customers and Braintrust grow.