Senior Backend Engineer - Kotlin, Spring Boot, Winkeln

Job Description We are looking for a Senior Backend Engineer to strengthen the service layer of an e‑banking platform. You will design, build, and operate highly reliable, secure microservices written in Kotlin with Spring Boot, integrated via Apache Kafka event streams, and deployed on Red Hat OpenShift. Kotlin is a core requirement and you will collaborate closely with the mobile engineering team. This role involves owning services end‑to‑end, from API contract design to production observability, influencing platform‑wide architecture, and acting as a technical reference for the squad and the wider backend chapter.

Company Overview At Merkle, a dentsu company, we power the experience economy by building apps, running CRM at scale, delivering technology architectures that support millions of users, and providing world‑class data, identity, and insights solutions. Backed by dentsu’s legacy of innovation and creativity, we have over 35 years of experience helping brands build loyalty, drive growth, and connect meaningfully with their audiences.

Responsibilities

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 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.

Required Qualifications

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.

Nice to Have

Bachelor’s degree in computer science, information technology, or equivalent experience.

Prior experience in regulated industries such as banking or fintech.

Familiarity with Spring Cloud and distributed tracing tools.

Experience with database migration tooling such as Flyway or Liquibase.

French or Italian, advantageous given the multilingual nature of the Swiss platform.

Benefits

25 days of holidays.

2 volunteer days for charitable activities.

Mental Health benefits: 3 extra wellness days on top of vacation days and ongoing mental health support.

First Aider and Employee Assistance program.

40‑hour week with overtime compensation.

Flexible working hours model (flextime).

Independent home office management.

State‑of‑the‑art, creative office space with ergonomically equipped workstations.

Pet friendly offices.

Full access to Dentsu Academy, on‑site learning sessions, and online language courses.

Learning Allowance: 40 additional hours per year for professional development.

Corporate benefits platform.

Referral bonus program.

Workation possibility.

Team events: company parties, monthly breakfasts, aperos.

We cherish the unique talents and perspectives of all individuals, welcoming applicants regardless of gender, gender identity, nationality, religion, ethnicity, cultural background, sexual orientation, age, physical or mental ability. Our hiring decisions are guided by qualifications and role‑specific requirements, ensuring a workplace free from discrimination and harassment.

Location St Gallen

Brand Merkle

Time Type Full time

Contract Type Permanent

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