Senior Backend Engineer

Design, develop, and maintain secure, scalable backend services and APIs using Kotlin and Spring Boot. Build and operate event-driven integrations via Apache Kafka including producers, consumers, Kafka Streams, and Avro schemas with exactly-once semantics. Own data models, query optimisation, and schema migrations across PostgreSQL and MySQL. Integrate services with observability, CI/CD, and DevOps tooling; support deployment and monitoring on OpenShift/Kubernetes. Apply security best practices in the realms of OAuth2/OIDC, authentication, authorisation, and encryption. Conduct code reviews, uphold engineering standards, and mentor junior engineers. Produce high-quality technical documentation covering design, implementation, and API contracts.

At Merkle, a dentsu company, we power the experience economy. Whether we’re building the next great app, running CRM at scale for global brands, delivering technology architectures that support millions of users, or providing world-class data, identity, and insights solutions, it’s all in the name of crafting experiences that set brands apart from the competition. Backed by dentsu's legacy of innovation and creativity originating in Japan, we’ve spent over 35 years helping brands build loyalty, drive growth, and connect meaningfully with their audiences. We’ve been named a global “Leader” by top industry analyst firms in categories as wide-ranging as digital transformation and commerce, experience design, engineering and technology integration, digital marketing, data science, CRM and loyalty, and customer data management.

• 5+ years of professional backend engineering experience.

• Proficiency in Kotlin.

• Strong hands-on experience with Spring Boot (Spring MVC, Security, Data JPA, Cloud, Actuator).

• Solid Apache Kafka experience including Kafka Streams, Schema Registry, and exactly-once semantics.

• Proficiency with PostgreSQL and MySQL: data modelling, query plans, replication, and working with connection pools (HikariCP).

• Practical experience with Kubernetes or OpenShift.

• Sound understanding of distributed systems, microservices architecture, and design patterns.

• Familiarity with OAuth2/OIDC and backend security fundamentals.

• Proficiency with Git and CI/CD practices.

• German B2+, primary language for team communication, documentation, and stakeholder interaction.

• English business proficient, used for technical standards and international tooling.