Senior Kotlin Backend Engineer

About the role

Paysera is looking for a Senior Kotlin Backend Engineer to design and build scalable payment APIs and core banking services. You will work in an AI‑focused environment, collaborating with product, delivery and engineering teams to deliver high‑performance financial solutions.

Key responsibilities

• Design and implement payment APIs using Kotlin and Spring Boot.
• Develop and maintain RESTful microservices, asynchronous workflows (Kafka or RabbitMQ) and reactive components (WebFlux, Kotlin Coroutines, R2DBC).
• Model complex financial workflows with Domain‑Driven Design and SOLID principles.
• Implement ORM layers with Hibernate/JPA, ensuring low error rates and efficient queries.
• Write automated test suites with JUnit/TestNG and maintain at least 80% code coverage.
• Integrate third‑party financial systems while meeting security and compliance standards.
• Optimize PostgreSQL/MariaDB schemas and queries for throughput over 1,000 TPS and latency under 200 ms.
• Monitor and debug distributed applications using Sentry, Graylog, Grafana and Kibana.
• Champion AI‑assisted development tools and mentor junior engineers.

Required profile

• 5+ years of backend development with Java and Kotlin.
• 2+ years of experience on complex, enterprise‑grade projects.
• Proven experience designing and delivering production microservices.
• Strong understanding of DDD, SOA, SOLID and event‑driven architectures.
• Hands‑on experience with PostgreSQL or MariaDB database design and optimization.

Required skills

• Kotlin
• Java SE/EE
• Spring Boot, Spring MVC, Spring Data
• Hibernate / JPA
• RESTful API design
• Microservices architecture
• Kafka or RabbitMQ
• PostgreSQL, MariaDB
• WebFlux, Kotlin Coroutines, R2DBC
• JUnit, TestNG
• Sentry, Graylog, Grafana, Kibana