Product Designer

About Langfuse

Langfuse is an open-source LLM Engineering Platform that helps teams build useful AI applications through tracing, evaluation, and prompt management. Now part of ClickHouse, we are building the "Datadog" for this category, addressing the challenges of building useful AI applications in both startups and enterprises. Langfuse is the largest open-source solution in its category, trusted by 19 of the Fortune 50 companies, with over 2,000 customers, more than 26 million monthly SDK downloads, and over 6 million Docker pulls.

Our merger with ClickHouse in January 2026 was strategic, as LLM observability is fundamentally a data problem, and Langfuse already ran on ClickHouse. This collaboration allows us to accelerate product development, maintain our commitment to open-source and self-hosting, and enhance our go-to-market and sales efforts to boost revenue. Langfuse was previously backed by Y Combinator, Lightspeed, and General Catalyst.

We are a small, engineering-heavy, and experienced team based in Berlin and San Francisco. We are actively hiring for engineering roles in EU timezones and expect one week per month in our Berlin office.

In short: We are looking for a Product Designer to take ownership of the user experience for the most widely adopted open-source LLM engineering platform. Langfuse is utilized by thousands of AI teams, including 19 of the Fortune 50, for tracing, evaluating, and managing their LLM applications. Our UI is crucial for engineers to navigate complex, data-dense workflows, and we need someone who can create an effortless experience.

Why Design at Langfuse

Your work as a Product Designer will directly shape how engineers build with AI. Langfuse often serves as the primary interface for engineers to debug, evaluate, and improve their LLM applications. The designs you ship will be used for hours daily by thousands of developers and non-developers. You'll receive direct feedback through GitHub issues, X, and our community Slack channels, as everything we build is open source (MIT-licensed) and immediately visible.

The design challenges at Langfuse are genuinely complex. You'll be designing for both technical and business users who prioritize information density, speed, and precision. Traces can contain dozens of nested LLM calls with extensive prompts and completions. Users need to configure evaluators, manage prompt versions, set up integrations, and build monitoring dashboards before they even begin analyzing results. Your role is to make both the initial setup and daily usage intuitive and straightforward.

You will also gain direct exposure to the development of cutting-edge LLM applications. Deeply understanding user problems will enhance your design skills and transform you into an expert in LLM engineering.

You will grow at Langfuse by

• Owning our product design end-to-end: As the first dedicated designer, you'll elevate the entire user experience, owning the design system and visual language, and setting the standard for Langfuse's look and feel.
• Making data-dense interfaces intuitive: You'll figure out how to present complex data like traces, scores, costs, latencies, token counts, prompt versions, and evaluation results in ways that allow engineers to quickly find what they need.
• Simplifying complex workflows: You'll map workflows for evaluations, experiment comparisons, prompt version management, and monitoring setup, identifying friction points and designing intuitive flows.
• Collaborating directly with product engineers: You'll pair with engineers, whiteboard solutions, and ship designs within our existing component system (shadcn/ui, Tailwind), creating reusable UI patterns for the team.
• Shipping design straight to code: You'll use AI coding tools to implement minor design fixes, build design system components, and polish UI details yourself, embracing a hands-on approach.

What we're looking for

• 3+ years of experience in designing complex web applications, including a portfolio showcasing product work that users loved.
• Ability to take ownership of our UI/UX, specifically made for developers.
• A desire to actively engage with users.
• A hard worker who thrives in a small, accountable team.
• Good understanding of best-in-class UI/UX principles.
• Excitement about open-source software and dev tools.

Bonus points

• Ability to ship frontend code (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 demonstrating craft and taste.

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

Process

We aim to complete the full hiring process to an offer letter in less than 7 days.

Tech Stack

Our tech stack includes a TypeScript monorepo with 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 portion of this, but we trust you will quickly pick up the rest.

How we ship

We trust you to take ownership for your area. You identify what to build, propose solutions (RFCs), and ship them. Everyone on the team considers both the user experience and technical implementation simultaneously. We use Linear for task management. While independent, you're never alone; team members are always available for whiteboard sessions, as 15 minutes of shared discussion can significantly improve output. We implement a maker schedule and communication approach with two recurring meetings weekly: a 15-minute Monday check-in on priorities and a 60-minute demo session on Fridays. Code reviews serve as mentorship, with new joiners receiving thorough reviews to learn the codebase, patterns, and system workings. We extensively use AI in our workflows to enhance user satisfaction and encourage experimentation with new tooling and AI workflows.

Why Langfuse (now part of ClickHouse)

• This role places you at the forefront of the AI revolution, partnering with engineering teams building defining technologies.
• We are an open-source devtools company that ships daily, communicates constantly with customers, and strives for exceptional developer experience, with reliability and performance as core requirements.
• Your work ships under your name, featured in changelog posts and launch week videos.
• You’ll own the full delivery end-to-end.
• We solve challenging engineering problems, from identifying impactful features for AI product performance to visualizing data-rich traces and processing terabytes of data daily.
• You'll work closely with the ClickHouse team, gaining insights into building a world-class infrastructure company.
• We are experiencing strong organic growth, further accelerated by ClickHouse's go-to-market strategies.
• User feedback is readily available via Slack and GitHub discussions, informing future development.
• You'll embark on a continuous learning journey in the fast-paced AI space, delivering essential tools to cutting-edge customers.

Key skills/competency

• Product Design
• UI/UX Design
• User Research
• Design Systems
• Data Visualization
• Workflow Optimization
• Interaction Design
• Prototyping
• Figma
• Front-end Development