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Senior Data Engineer (f/m/d)
Job Description
About the Opportunity
We are hiring a Senior Data Engineer to join the Playtime Data Science team at adjoe in Hamburg.
This role sits at the core of a large-scale AdTech ecosystem that processes billions of events and powers real-time advertising decisions for hundreds of millions of users worldwide. You will help design and operate the data backbone that enables machine learning, experimentation, and high-performance ad delivery.
The work directly supports a fast-growing platform backed by Bertelsmann and operating across global hubs including Hamburg, Boston, Singapore, and Tokyo.
What You Will Work On
Real-Time Data & Streaming Systems
You will build and scale the infrastructure that powers real-time decisioning systems.
- Develop and maintain high-throughput streaming pipelines using Kafka and Flink
Implement real-time feature engineering for ML systems
Ensure low-latency processing for millions of events per second
Support systems handling terabytes of daily data ingestion
EU data infrastructure framework
Feature Store & Data Platform Engineering
You will play a key role in evolving the company’s Feature Store and data architecture.
- Build scalable real-time feature pipelines
Enable data scientists to easily contribute and consume features
Improve data modelling across multiple layers (raw, processed, curated)
Support evolution toward modern data architectures (e.g., lakehouse models)
Pipeline Performance & Optimisation
You will ensure that large-scale data systems remain efficient and reliable.
- Identify bottlenecks in ETL and streaming pipelines
Optimise data workflows for speed and cost efficiency
Reduce latency in distributed processing systems
Improve scalability of existing data infrastructure
Collaboration with Data Science & Engineering Teams
You will act as a technical bridge between multiple disciplines.
- Work closely with Data Scientists on ML feature requirements
Collaborate with Backend Engineers for production integration
Translate experimental requirements into scalable data solutions
Support low-latency online machine learning systems
EU AI & digital systems guidance
Data Architecture & System Design
You will contribute to long-term architectural decisions.
- Design robust, multi-layer data architectures
Maintain and evolve data lake infrastructure
Work with distributed storage and query systems
Support decisions around next-generation data platforms
EU cloud & infrastructure policy
Data Quality & Governance
You will ensure reliability, consistency, and trust in data systems.
- Implement data validation and monitoring frameworks
Define and enforce data quality standards
Build observability systems for pipelines and features
Ensure compliance with internal governance requirements
Tech Environment
The engineering stack is modern, open-source driven, and cloud-based:
- Streaming & Processing: Apache Kafka, Apache Flink (Java)
Backend & Services: Go, Python
Infrastructure: Kubernetes, Terraform, AWS
Storage: S3, Druid, DynamoDB, Redis
ML Infrastructure: TensorFlow, PyTorch, Triton, TensorFlow Serving
Orchestration: Apache Airflow
Monitoring: Prometheus, Grafana, ELK, OpenObserve
EU cloud infrastructure context
Scale You’ll Work With
This is a high-scale distributed system environment:
- Thousands of requests per second
~100,000+ ML predictions per second
~2TB real-time data ingestion daily
Sub-100ms p99 latency requirements
100+ production data pipelines and workflows
What We’re Looking For
Experience
- 5+ years in software or data engineering roles
Strong background in modern data engineering systems
Experience with large-scale, real-time data processing
Proven work with distributed systems at TB/day scale
EU labour mobility information
Technical Expertise
- Strong proficiency in Java (core requirement)
Experience with Kafka, Flink, or similar streaming systems
Familiarity with AWS and cloud-native architectures
Knowledge of SQL and both relational & NoSQL databases
Experience with orchestration tools such as Airflow or Kubeflow
Understanding of data modelling and layered architectures (e.g., medallion approach)
Data & Systems Thinking
- Strong ability to debug and optimise complex pipelines
Experience improving system performance under load
Understanding of data quality and observability principles
Ability to design scalable and maintainable data platforms
Collaboration & Communication
- Experience working with Data Science teams on ML systems
Ability to translate technical concepts across disciplines
Strong problem-solving mindset in complex environments
Bonus Skills
- Hands-on AWS, Kubernetes, Terraform experience
Exposure to dbt and semantic data layers
Familiarity with lakehouse or modern data warehouse architectures
EU digital transformation strategy
What We Offer
Career Development
- Structured feedback and growth programs
Exposure to large-scale distributed systems
Opportunities to shape next-generation data architecture
EU employment & skills support
Work Model
- Hybrid setup (3 office days per week)
Flexible working hours
30 vacation days per year
3 weeks remote work annually
EU working conditions overview
Relocation Support
- Visa assistance for international candidates
Relocation bonus and onboarding support
Help with settling in Hamburg
EU immigration guidance
Wellbeing & Lifestyle
- In-house gym and fitness classes
Mental health support via Employee Assistance Program
Modern office with Alster lake views
Snacks, drinks, and social spaces
EU occupational health overview
Culture
- International engineering-driven environment
Hackathons, events, and team gatherings
Strong focus on collaboration and innovation
Celebrating achievements as a team
About adjoe / applike group
adjoe is a high-growth AdTech company redefining mobile advertising through AI-driven rewarded ad systems. Its Playtime platform connects advertisers and publishers with hundreds of millions of users globally, enabling scalable monetisation and engagement.
The company operates at the forefront of Europe’s digital advertising and AI infrastructure landscape.
Why This Role Matters
This position is ideal for someone who wants to:
- Build and scale real-time data infrastructure at global scale
Work on systems processing billions of events
Shape the foundation of ML-powered AdTech platforms
Collaborate with top engineers and data scientists
