Senior Backend Software Engineer with Kotlin

NTT DATA Europe & Latam is seeking a Senior Backend Software Engineer to build and operate backend services for an internal platform using decisioning and machine learning to deliver personalised customer experiences. The role owns backend capabilities end-to-end, contributes to technical direction and engineering standards, and collaborates with frontend and data teams and client stakeholders.

Responsibilities:

• Design, build, maintain, and operate backend services and REST APIs using Kotlin and Ktor
• Own backend-led work from discovery and domain design through implementation, automated testing, deployment, observability, production support, and iteration
• Model and manage data in PostgreSQL, including schema design, queries, performance tuning, and database migrations
• Use Terraform to define, provision, and manage cloud infrastructure as code
• Build event-driven and batch data-processing workflows
• Collaborate with data scientists and adjacent teams on reliable integrations with internal services, data platforms, and machine-learning systems
• Improve service resilience, security, logging, metrics, tracing, and operational tooling
• Use unit, property-based, integration, contract, behaviour-driven, and end-to-end testing where appropriate
• Contribute to technical design, code reviews, documentation, and the maintainability of a large codebase
• Design stable interfaces and integration contracts that enable frontend, data, and downstream teams to deliver end-to-end capabilities
• Work directly with client stakeholders and delivery partners as requirements evolve, explaining technical trade-offs and adapting backend scope without compromising reliability, maintainability, or operational quality

Requirements:

• BSc/MSc in Computer Science or related field
• 6/8+ years of experience in software engineering
• Strong backend development experience with Kotlin and Ktor, Java, or another modern JVM language
• Experience designing, delivering, and maintaining production APIs and distributed services
• Strong relational database and SQL capability, including data modelling, schema evolution, and query or performance considerations
• Experience with asynchronous programming, concurrency, event streaming, or resilient integration patterns
• Experience developing and operating cloud-native applications using containers, managed services, identity, networking, observability, and infrastructure-as-code such as Terraform
• Evidence of automated testing and responsibility for software quality
• Evidence of independently owning substantial backend work and making sound trade-offs between delivery, maintainability, reliability, and performance
• Designing stable service interfaces and integration contracts for use by frontend, data, or downstream systems
• Experience contributing to design decisions, code reviews, technical documentation, troubleshooting, and the development of other engineers
• Evidence of client-facing engineering delivery in demanding or ambiguous environments, including explaining technical trade-offs, responding to changing requirements, and setting realistic expectations
• Kafka, Avro, NoSQL stores, event-driven architecture, or high-volume data processing
• GCP services, cloud migration, infrastructure portability, and operational-parity validation
• Spark, Scala, Python-based data pipelines, or integration with machine-learning systems
• API contract testing, schema evolution, service compatibility, or consumer-driven contract approaches
• GitLab CI/CD, OpenTelemetry, property-based testing, or behaviour-driven development
• Experimentation platforms, rules engines, recommendation systems, or customer decisioning