Product Designer

Open Source LLM Engineering Platform that helps teams build useful AI applications via tracing, evaluation, and prompt management (mission, product). We are now part of ClickHouse.

We're building the "Datadog" of this category; model capabilities continue to improve but building useful applications is really hard, both in startups and enterprises

Largest open source solution in this category: trusted by 19 of the Fortune 50, >2k customers, >26M monthly SDK downloads, >6M Docker pulls

We joined ClickHouse in January 2026 because LLM observability is fundamentally a data problem and Langfuse already ran on ClickHouse. Together we can move faster on product while staying true to open source and self-hosting, and join forces on GTM and sales to accelerate revenue

Previously backed by Y Combinator, Lightspeed, and General Catalyst

We're a small, engineering-heavy, and experienced team in Berlin and San Francisco. We are also hiring for engineering in EU timezones and expect one week per month in our Berlin office (how we work).

In Short: We're hiring a product designer to own the user experience of the most widely adopted open source LLM engineering platform. Langfuse is used by thousands of AI teams — including 19 of the Fortune 50 — to trace, evaluate, and manage their LLM applications. Our UI is where engineers make sense of complex, data-dense workflows, and we need someone who can make that experience feel effortless.

Your work will shape how engineers build with AI.

Langfuse is often the primary interface engineers use to debug, evaluate, and improve their LLM applications. The designs you ship will be used for hours each day by thousands of developers and non-developers. They'll tell you about it in GitHub issues, on X, and in our community Slack channels. Everything we build is open source (MIT-licensed) and immediately visible.

The design challenges here are genuinely hard. You're designing for technical users and business users alike who care about information density, speed, and precision. Traces contain dozens of nested LLM calls with massive prompts and completions. Users need to set up evaluators, manage prompt versions, configure integrations, and build monitoring dashboards before they even start analyzing results. You need to make both the setup and the daily use feel intuitive and easy.

You will also have direct exposure to how cutting-edge LLM applications are built. Deeply understanding the problems our users solve will make you a better designer and along the way makes you an expert on LLM engineering yourself.

• Owning our product design end-to-end. You'll be the first dedicated designer at Langfuse. Today, our engineers design as they build, which has gotten us far, but we need someone who can elevate the entire experience. You'll own the design system, and visual language across the product. You'll set the standard for how Langfuse looks and feels.

• Making data-dense interfaces intuitive. Langfuse surfaces traces, scores, costs, latencies, token counts, prompt versions, and evaluation results. You'll figure out how to present complex, nested data in ways that help engineers find what they need fast.

• Simplifying complex workflows. Our users run evaluations across datasets, compare experiment results, manage prompt versions, and set up monitoring. You'll map these workflows, identify friction, and design flows that feel obvious in hindsight.

• Collaborating directly with product engineers. You'll pair with engineers, whiteboard solutions together, and ship designs that work within our existing component system (shadcn/ui, Tailwind). You'll create reusable, consistent UI patterns that the whole team can build with.

• Shipping design straight to code. You'll use AI coding tools to implement smaller design fixes, build components for the design system, and polish UI details yourself. We are not looking for a perfect engineer here but for someone who can help themselvesherself.

• 3+ years of experience in designing complex web applications, incl. a portfolio showcasing product work that users loved

• Take ownership of our UI/UX made for developers

• You want to talk to users

• Hard worker and thrive working in a small and accountable team

• Good understanding of best in class UI/UX

• Excited about open source software and dev tools

Bonus points:

• You can ship frontend code (we use Next.js, Tailwind, shadcn/ui)

• ML/AI experience or familiarity with the LLM tooling ecosystem

• Former founder or early startup experience

• Contributions to open source projects or design systems

• Side projects that show craft and taste

No candidate checks all boxes. If you feel you are a good fit for this role, please go ahead and apply.

We can run the full process to your offer letter in less than 7 days (hiring process).

We run a TypeScript monorepo: Next.js on the frontend, Express workers for background jobs, PostgreSQL for transactional data, ClickHouse for tracing at scale, S3 for file storage, and Redis for queues and caching. You should be familiar with a good chunk of this, but we trust you'll pick up the rest quickly (Stack, Architecture).

Link to handbook

• We trust you to take ownership (ownership overview) for your area. You identify what to build, propose solutions (RFCs), and ship them. Everyone here thinks about the user experience and the technical implementation at the same time. Everyone manages their own Linear.

• You're never alone. Anyone from the team is happy to go into a whiteboard session with you. 15 minutes of shared discussion can very much improve the overall output.

• We implement maker schedule and communication. There are two recurring meetings a week: Monday check-in on priorities (15 min) and a demo session on Fridays (60 min).

• Code reviews are mentorship. New joiners get all PRs reviewed to learn the codebase, patterns, and how the systems work (onboarding guide).

• We use AI as much as possible in our workflows to make our users happy. We encourage everyone to experiment with new tooling and AI workflows.

• This role puts you at the forefront of the AI revolution, partnering with engineering teams who are building the technology that will define the next decade(s).

• This is an open-source devtools company. We ship daily, talk to customers constantly, and fight for great DX. Reliability and performance are central requirements.

• Your work ships under your name. You'll appear on changelog posts for the features you build, and during launch weeks, you'll produce videos to announce what you've shipped to the community. You’ll own the full delivery end to end.

• We're solving hard engineering problems: figuring out which features actually help users improve AI product performance, building SDKs developers love, visualizing data-rich traces, rendering massive LLM prompts and completions efficiently in the UI, and processing terabytes of data per day through our ingestion pipeline.

• You'll work closely with the ClickHouse team and learn how they build a world-class infrastructure company. We're in a period of strong growth: Langfuse is growing organically and accelerating through ClickHouse's GTM. (Why we joined ClickHouse)

• If you wonder what to build next, our users are a Slack message or a Github discussions post away.

• You’re on a continuous learning journey. The AI space develops at breakneck speed and our customers are at the forefront. We need to be ready to meet them where they are and deliver the tools they need just-in-time.