Who We AreWe are looking for a Senior Backend Software Engineer to design, build, and operate backend services for an internal platform that leverages decisioning and machine learning to deliver personalised customer experiences. This senior individual contributor role focuses on Kotlin, APIs, PostgreSQL, cloud technologies, streaming, and distributed data processing, delivering backend capabilities end-to-end while collaborating closely with frontend and data teams.The role drives key technical outcomes, contributes to architecture and engineering standards, mentors engineers, and works within the guidance of the Technical Lead. As a client-facing consultant, you will provide clear communication, sound technical judgement, and pragmatic solutions in complex delivery environments.Technology StackBackend: Kotlin and KtorData and messaging: PostgreSQL, Kafka, and SparkFrontend: API contract testing, schema evolution, service compatibility, or consumer-driven contract approachesCloud and delivery: AWS, GCP, Docker, Terraform, and GitLab CI/CDQuality and operations: Kotest, property-based testing, Cucumber, Playwright, and observability toolingWhat You'll Be DoingDesign, build, maintain, and operate backend services and REST APIs using Kotlin and KtorOwn backend-led work from discovery and domain design through implementation, automated testing, deployment, observability, production support, and iterationModel and manage data in PostgreSQL, including schema design, queries, performance tuning, and database migrationsUse Terraform to define, provision, and manage cloud infrastructure as codeBuild event-driven and batch data-processing workflowsCollaborate with data scientists and adjacent teams on reliable integrations with internal services, data platforms, and machine-learning systemsImprove service resilience, security, logging, metrics, tracing, and operational toolingUse unit, property-based, integration, contract, behaviour-driven, and end-to-end testing where appropriateContribute to technical design, code reviews, documentation, and the maintainability of a large codebaseDesign stable interfaces and integration contracts that enable frontend, data, and downstream teams to deliver end-to-end capabilitiesWork directly with client stakeholders and delivery partners as requirements evolve, explaining technical trade-offs and adapting backend scope without compromising reliability, maintainability, or operational qualityWhat You'll Bring AlongBSc/MSc in Computer Science or related field6/8+ years of experience in software engineeringStrong backend development experience with Kotlin and Ktor, Java, or another modern JVM languageExperience designing, delivering, and maintaining production APIs and distributed servicesStrong relational database and SQL capability, including data modelling, schema evolution, and query or performance considerationsExperience with asynchronous programming, concurrency, event streaming, or resilient integration patternsExperience developing and operating cloud-native applications using containers, managed services, identity, networking, observability, and infrastructure-as-code such as TerraformEvidence of automated testing and responsibility for software qualityEvidence of independently owning substantial backend work and making sound trade-offs between delivery, maintainability, reliability, and performanceDesigning stable service interfaces and integration contracts for use by frontend, data, or downstream systemsExperience contributing to design decisions, code reviews, technical documentation, troubleshooting, and the development of other engineersEvidence of client-facing engineering delivery in demanding or ambiguous environments, including explaining technical trade-offs, responding to changing requirements, and setting realistic expectations Nice to have:Kafka, Avro, NoSQL stores, event-driven architecture, or high-volume data processing GCP services, cloud migration, infrastructure portability, and operational-parity validationSpark, Scala, Python-based data pipelines, or integration with machine-learning systemsAPI contract testing, schema evolution, service compatibility, or consumer-driven contract approachesGitLab CI/CD, OpenTelemetry, property-based testing, or behaviour-driven developmentExperimentation platforms, rules engines, recommendation systems, or customer decisioning Show more Show less