Founding Lead Product Engineer (m/f/d)

About DojoStack

DojoStack is building a voice-native, canvas AI tutor that you talk to and sketch with on your tablet or phone. It teaches STEM at the level of a great human tutor - for the 1.5 billion learners who will never afford one.

Everybody wants to build an AI tutor… Building a product that rivals a real human is close to impossible. A demo takes a weekend, but shipping something that parents and students trust means being right 99%+ of the time. The last stretch is a hardcore infrastructure game: evals, fine-tuning, human-in-the-loop, agent graph engineering, GitOps, … the infrastructure that generic LLM wrappers never touch.

We are infrastructure-grade under the hood and consumer-grade on the surface, which is extremely rare in one company.

Our team has founded and scaled data-infrastructure companies to hundreds of millions in value. Now we’re applying that experience to education: truly personalized learning at global scale. We’re backed by some of the best investors in the world and are extremely well funded for the journey ahead.

Based in Berlin, DojoStack is a tight-knit group of top 1% engineers, designers, and researchers we’ve worked with before. We move fast, own problems end to end, and care deeply about what we build.

If you want to build real AI with urgency, autonomy, and purpose, we’d love to meet you.

About the role

We’re not looking for a traditional Product Engineer. We’re looking for a weapon → someone insanely smart, systems-minded, and dangerous at turning ambiguity into working products.

You’ll work directly with the co-founders (CPO and CEO) to design, build, and scale the core engine behind our agentic system. One day you’re prompting models and debugging evals. The next, you’re architecting agent graphs in LangGraph, tracing a regression through git history, or defining how human feedback loops power our models at scale.

You’ll move across engineering, product, and infrastructure to push the system forward. You’ll think in probabilities, optimize for upside, and build guardrails to catch the edge cases. This role isn’t for someone who waits for permission. You’ll own strategy and execution, obsess over data, and ship like your life depends on it. If something needs doing, you do it.

What you will do

• Design end-to-end systems that power our agents - graphs, tools, memory, evals
• Create scalable agentic infrastructure for generating, reviewing, and improving educational content
• Collaborate with engineers and design to ship reliable, user-ready platforms
• Monitor how real users interact with the system and redesign what doesn’t click
• Build processes to fine-tune and evaluate LLMs, with human-in-the-loop feedback at the core
• Balance exploration and execution to deliver world-class quality
• Lead as we scale: hire and mentor the product engineers who join you, and set the bar for how we build

Requirements for the role

• 2+ years of experience in high-ownership, fast-paced environments
• Strong empathy for users and a sharp product intuition
• Comfortable coding and shipping complete product experiences
• Fluent in the modern AI stack — you’ve built with LLM/agent frameworks (LangGraph or similar) and you think in systems and architecture, not just features
• Autonomous, fast learner who adapts quickly
• Clear, confident communicator who can drive alignment across teams
• Analytical thinker with a bias for action

What we offer

• Real ownership - in both scope and equity (0.5% to 2.0% equity for core team members)
• Competitive salary
• A steep personal growth curve, with expanding responsibility
• The chance to work at the frontier of applied AI
• A high-trust team and a mission that matters

You’ll learn what excellent looks like

Most people go through a whole career without seeing truly excellent work up close. We pride ourselves on having the battle scars to know what excellence in product building looks like → from scalable data models to GitOps all the way to end-user design taste, and scalable internal processes. You get to learn them here up close. Your success is our success, and we’re committed to teaching you these best practices.

You might excel if you…

• Have founded or been early at a startup
• Have a trail of things you built that nobody asked for (side projects, open source, a product with real users)
• Are highly competitive, ambitious, and energized by intensity
• Thrive in fast-paced environments with constant context switching
• Enjoy tackling both technical and non-technical problems

1. 01 · White belt

   Application Review

   Your work counts for more than your resume.

2. 02 · Yellow belt

   Intro Call

   30 min

   Who you are, what drives you, what you’ve shipped.

3. 03 · Orange belt

   Proof of Work

   30 min

   Walk us through the best thing you’ve built — or a small task, if your work is locked away.

4. 04 · Green belt

   CEO Interview

   30 min

   Ambition, expectations & mutual fit.

5. 05 · Blue belt

   Reference Checks

6. 06 · Purple belt

   Paid Trial Week in Berlin

   5 days building with us - we offer exactly one slot each month for one candidate.

7. 07 · Black belt

   Offer

   Within 48 hours of your Friday demo.

Location

This role is based at our HQ in Berlin, Germany. In-person collaboration is how we build speed and trust. You’ll be expected in the office at least 3 days a week, with flexibility to work remotely up to 2 days.

How to apply

Apply with the form below: your name and email are enough. Add your resume, LinkedIn or GitHub — or skip the resume and just link the best thing you’ve built.