Senior Backend Engineer - JVM (Java/Kotlin) & AWS
adsquare
Passion – Solving complex challenges with great people, tech, and data.
Niche – Location Intelligence for Programmatic Advertisers.
Our core values are integral to everything we do:
Drive: We turn ambition into action.
Resilience: We adapt, persevere, and grow stronger.
No BS: We value honesty, transparency, and clear communication.
Humble: We choose modesty over vanity and let results speak for themselves.
Moral Compass: We do the right thing with fairness, integrity, and respect.
We seek candidates who not only bring top-tier technical expertise but also embody these values in every aspect of their work.
]]>Your primary mission is to build reliable, high-throughput backend services on the JVM that process and serve large volumes of location intelligence data in real time.
You will work in a highly autonomous, cross-functional team and be expected to proactively identify problems, propose solutions, and drive them to production.
In this role, you will:
Design and evolve distributed backend systems with a strong focus on scalability, performance, and reliability
Own services end-to-end: from architecture decisions to production operations
Build and operate cloud-native systems on AWS
Collaborate closely with Product and Data teams to deliver impactful features
Continuously improve system design, engineering practices, and team effectiveness
Must have:
4–5+ years of experience building backend systems in production environments
Strong expertise in Java or other JVM-based languages (Kotlin, Scala) and the Spring ecosystem
Proven experience designing and operating distributed systems under real-world load
Hands-on experience with AWS, including designing cloud-native architectures
Strong understanding of concurrency, data consistency, and system reliability
Experience working with PostgreSQL or other relational databases in high-throughput environments
Ability to debug and optimize systems in production (performance, memory, latency)
A proactive approach: you identify problems, take ownership, and drive solutions without close supervision
Nice to have:
Have worked on systems processing large volumes of data or high request throughput
Understand trade-offs between different architectural approaches (e.g. synchronous vs asynchronous processing)
Are comfortable making decisions in ambiguous situations
Maintain and evolve existing partner integrations, ensuring reliability and scalability
Design and build new integrations to deliver large-scale data to our partners
Contribute to migrating and adapting services to a cloud-native architecture on AWS
Monitor system health, troubleshoot production issues, and improve overall system stability
Data-intensive systems or high-throughput backend services
Cloud-based architectures (especially AWS)
Partner integrations or API-driven systems
Systems evolving from monolithic to distributed or cloud-native architectures
Core technologies:
Java (11+) and Kotlin
Spring / Spring Boot
AWS (e.g. S3, SQS/SNS, Lambda)
PostgreSQL
In our environment, you will also work with:
Infrastructure as Code (Terraform)
NoSQL databases (e.g. MongoDB)
Container orchestration (Kubernetes)
Data processing tools (e.g. Athena, Glue, Batch, Step Functions)
We do not expect prior experience with all of the above, but you should be comfortable working with modern cloud infrastructure and data-intensive systems.
]]>We work with a high level of ownership - engineers are expected to make decisions, propose improvements, and drive changes from idea to production.
You will be able to:
Shape system architecture and influence key technical decisions
Take ownership of services and drive their evolution over time
Contribute to how we scale our systems and data processing capabilities
Work in an environment where initiative and accountability are valued
Senior Backend Engineer - JVM (Java/Kotlin) & AWS
adsquare · Berlin