AI Engineering Intern

About Mercura

Mercura is building AI software for the backbone of our economy.

Backed by Y Combinator, we raised a heavily oversubscribed round at one of the highest valuations in our cohort. As one of Europe's fastest growing startups, we surpassed $2M in ARR in our first year . Now, we are looking for team members ready to go all-in to help us reach our next milestone: $10M ARR by the end of 2026 .

One of our co-founders, Lukas, grew up in a trades family that has been active in the construction industry for over 115 years. Having worked on the construction site himself, he learned first-hand how slow and manual quoting still is in the industry.

In an era where AI becomes ubiquitous, we set out on a deeply personal mission: bring AI to the backbone of our economy - to the companies that keep our world running. To amplify human expertise and free people to do what only humans can do.

About the role

We’re looking for AI Engineering Interns to help us build AI systems end-to-end. This is a fast-paced, hands-on role for candidates with high agency . At Mercura, you will collaborate closely with the best engineers and gain real-world experience in building AI applications in an industrial B2B context.

If you're excited about software engineering and AI , this is your opportunity to learn, experiment, and contribute.

What you will be working on

• Work across the full stack to build AI agents end-to-end
• Work with embeddings and fine-tune LLMs for classification and reranking
• Optimize algorithms for product search
• Apply RLHF & DPO to align LLMs with human feedback
• Build data pipelines to process large-scale unstructured data efficiently
• Make our backend scalable, stable and efficient

What we're looking for

• High agency and experience with building software and iterating quickly
• Experience with NLP, LLMs, Embeddings, ML, and AI-powered applications
• First Experience with full-stack development (TypeScript, Python, React, Next)
• Strong problem-solving capabilities and willingness to learn new technologies
• You’re excited to strive for excellence and build software in a fast-paced startup environment
• You want to work in-person in Munich with more intensity than in a 9-5 job
• You are available for a minimum 4-month internship
• You are done/at the end of university and could join full-time within six months after the internship

Company Perks

• Free team dinner (up to 4x/week)
• UrbanSportsClub membership - join our team workouts 3x/week
• Easy relocation to Munich — our office is located in the Werk1 Startup Incubator, where you can rent a 1-bedroom apartment right next to the office for just €800/month
• Access to any AI or productivity tools you need

Your team & mentors

You will work with

• Sean (Co-Founder & CTO; Silver Medallist at the International Physics Olympiad (IPhO))
• Ben (prev. AI Engineer at Aleph Alpha)
• Mark (prev. SWE at Capital One, Cambridge Graduate)

About the interview

Step 1: Intro call

Casual intro meeting with one of the founders to get to know each other and introduce Mercura.

Step 2: Technical interview

A take-home technical challenge to showcase your skills, followed by a call to walk us through your approach, insights, and solution for the take-home exercise.

Step 3: Personal Fit

Meet another co-founder to get a feel for our culture and working style.

Step 4: Offer

If we see a great fit, you will get an offer, including a competitive compensation package.

Why Mercura

• Join an ambitious team that feels like family : Your future colleagues are experienced operators, ex-founders, Science Olympiad medallists, and top graduates from places such as Google, Bain, MIT, TUM, Harvard, CDTM, and Cambridge . We bring extraordinary people together and deeply invest in your growth as your mentors, teammates and friends. We care, trust, and support one another like family, and we make sure that fun is at the heart of everything we do.
• Work with the latest tech : AI is at the core of our product, and use the latest tech across our product and processes to tackle meaningful challenges and shape how users interact with AI.
• Thrive in a high-growth, high-commitment environment : We’re growing extremely fast because we always put our work and our customers first. If you excel in fast-paced settings and want to grow as part of something big from day one, Mercura is for you.
• Build something with real-world impact : We ship code that directly helps a massive, yet overlooked manual industry run more efficiently and sustainably. With us, you can work on AI that contributes to economic growth and stability on a huge scale.
• Build a company : As an early team member, you will have a direct, lasting impact on our culture, processes, technology, and product. Joining us offers immense rewards: ownership, financial upside, and hands-on experience building a company from the ground up. Our track record speaks for itself - over five Mercura alumni have gone on to found their own companies and raise millions after their time with us.

About the Founders

We are Lukas, Stefan & Sean , the co-founders of Mercura.

We share a deep commitment to excellence and the discipline to pursue what others might consider impossible.

Two of us come from non-academic families, and we all know what it means to create our own paths and overcome barriers. This experience shapes our belief in equal opportunity and fuels our dedication to social mobility.

Lukas (left) is responsible for business development at Mercura. With his background as a Data Scientist at Allianz and at Google in Silicon Valley, he brings extensive expertise in data and AI. Lukas’ family has been active in the construction industry for over 100 years, giving him a deep understanding and passion for the sector's specific needs.

Sean (middle) is responsible for technical development at Mercura. As a top 0.01% physicist, Sean earned a Silver medal for Germany at the International Physics Olympiad (IPhO), began researching with the Max Planck Institute at the age of 16, and has since published at leading machine learning conferences.

Stefan (right) leads product development at Mercura. Previously, he worked in management consulting at Bain & Company, where he helped manufacturers improve their operations. Stefan leverages his research experience at the Massachusetts Institute of Technology (MIT) and Harvard Business School to develop innovative solutions for the industry.

At Mercura, we believe that the best ideas emerge when people from different backgrounds collaborate together. We hire based on ability, mindset, and values, and we live by one simple rule: the best idea wins.

Beyond Mercura, we actively support initiatives that promote diversity and gender equity and commit a portion of our personal income each year to organizations expanding opportunity for others.

Our company values

Customer first. We stay close to our customer’s reality and use their feedback to build what truly matters and earn their lasting trust.

Ownership. We take responsibility end-to-end and act proactively to pursue the most ambitious goals.

Enjoy the ride. We build a culture where people can be themselves, have fun doing meaningful work, and celebrate wins along the way.

Let the best ideas win. We challenge each other respectfully and judge ideas by merit, not who said it.

Down-to-earth. We are approachable, humble, and hands‑on, bringing both heart and mind to everything we do.