Senior Data Engineer (m/f/d) – Customer Identity Resolution

Our mission

We are on a mission to save our planet - one second hand product at a time.

As Senior Data Engineer, you will own one of our most business-critical data assets: the system that links customer identities across our businesses and powers better decisions in marketing, CRM, reporting, and analytics. You will join our Business Intelligence & Data Engineering team and work closely with Data Engineers and Business Analysts to build reliable, scalable, and trustworthy customer identity data.

Your mission

• Own the end-to-end pipeline that creates the unified customer_uuid across Books & Media and Fashion
• Maintain and evolve our customer identity master data with a strong focus on accuracy, reliability, and production quality
• Improve our probabilistic identity resolution model and make matching decisions measurable, transparent, and explainable
• Build scalable and cost-efficient data pipelines across BigQuery, GCS, and Cloud Run Jobs
• Introduce diagnostics, monitoring, and structured validation for every relevant model change
• Identify and resolve edge cases in customer matching logic before they become production issues
• Work closely with business and technical stakeholders to turn complex matching challenges into robust data solutions

Our Tech Stack

• BigQuery
• SQL
• Python
• Airflow
• Splink
• Google Cloud Storage
• Cloud Run Jobs
• Pub/Sub

Your profile

Must-Have:

• 5+ years of experience in production data engineering
• Strong experience with BigQuery and advanced SQL in large-scale analytical environments
• Strong Python skills for production-grade data engineering
• Solid Airflow experience and a strong understanding of reliable orchestration patterns
• Hands-on experience with incremental pipelines and idempotent data processing
• Experience with probabilistic record linkage or entity resolution in production
• Strong understanding of data quality, matching logic, and precision/recall trade-offs
• A careful, structured, and ownership-driven way of working
• Strong communication skills and the ability to explain technical decisions clearly

Nice-To-Have:

• Experience with Splink and probabilistic record linkage tools
• Experience with Cloud Run Jobs, GCS, and event-driven patterns in GCP
• Experience with Pub/Sub as a source in data pipelines
• Familiarity with data format trade-offs such as Parquet, Avro
• Experience with dbt
• Exposure to downstream BI use cases
• Experience in e-commerce or marketplace environments
• German language skills

You can look forward to

• Flexible working hours: We follow a hybrid work model with 20 in-office days per quarter to foster important personal interaction while enabling a modern, flexible way of working. The remaining days can be worked from home, and you also have the option to spend up to 6 weeks per year working from countries within EU. You’ll also benefit from flexible working hours to fit your individual needs.
• Open work environment: We work together in a bright, open-plan office where even the few existing doors are always open. Our teams are motivated and open to new ideas. Bring your creativity to the table and make things happen! If you need a moment of peace, you can retreat to a cozy corner of the medimops library in the break room, or recharge with a game of foosball, table tennis, or PlayStation.
• Training: momox is only as good as you. That's why you will find room and budget for your individual professional development with language classes, internal training, conferences, (online) courses and more.
• Sustainability: We love second-hand and incorporate our sustainable business idea into the office routine with simple methods like using eco-friendly supplies, double-sided printing, energy-saving modes on devices, waste separation, etc. In doing so, we take responsibility and integrate sustainability into all our activities.
• Individual work environment: Design your ergonomic workspace just the way you like it – with height-adjustable desks and the laptop of your choice (MacBook or ThinkPad). If things get a bit noisy in the office, your Bose noise-cancelling headphones ensure uninterrupted focus. If needed, we can also provide you with an ergonomic chair or additional monitors for your home office.
• Office dogs: Our office dogs contribute to a relaxed work atmosphere and are always happy to receive some extra cuddles.
• Sport and fitness offers: During the week, you have the opportunity to take part in various sports activities. Whether it's online training, massages, or stretching at your desk – there's something for everyone. You can also get a discounted membership for Urban Sports Club or Wellhub.
• Company discounts: As a momoxian, you can look forward to a monthly voucher for our momox Fashion online shop, as well as medimops. Additionally, you benefit from numerous company discounts from our partners.
• Team events: Having fun at work and celebrating our successes together are core to our values. That’s why we regularly come together at various events to connect, get to know each other better, and strengthen our team spirit.
• 1/2 day off on your birthday: Celebrate your birthday with half a day of vacation! Come in later, leave earlier, or simply take an additional half day off to have your entire birthday free – provided your birthday falls on a regular working day. Additionally, you get half a day off on December 24th and 31st.