Backend Developer (Kotlin)

About Quartz Quartz is reimagining wealth management through personalised intelligence. It's the first wealth platform that truly learns from you, understands your goals, and helps you make confident, informed decisions all in one secure platform. Get the experience of a personal banker that works with you 24/7, at a fraction of the cost. About The Role We're looking for a Backend Engineer to help build the core of how Quartz works — the systems that aggregate user data, power Charlie (our AI advisor), and make personalised wealth advice possible at scale. You'll write Kotlin day-to-day, work across greenfield services and existing systems, and make the kind of early engineering decisions that compound for years. Expect to partner closely with the Head of Engineering on architecture, and with product and ML on how the backend shapes what users experience. This role is for someone who excels at first principle thinking, is comfortable owning systems end-to-end, and moves with the urgency of a startup while holding the rigour a financial platform demands. If you're looking to do meaningful work and you're not driven by a nine to five mentality, you might be just who we're looking for. Our technology stack KotlinSpringBoot, ArrowPostgreSQLJUnit, Mockk, Springmockk What you'll be doing Designing and building the APIs and services that power Quartz's mobile and web appsBuilding the data infrastructure that aggregates user accounts and feeds Charlie, our AI advisorOwning features end-to-end — from API design through to production rollout and observabilityPartnering with ML and product to translate advisory logic into reliable, testable backend behaviourSetting the bar on code quality, testing, and engineering rigour alongside the Head of Engineering What you'll need Fluency with Kotlin or Java5+ years of experience in backend developmentTo be a quick learner with an ambitious attitude and results-driven personalityExperience in a start-up or scale-up (at least have started something as a side project!)Fluency in English Nice to have Experience in financeExperience in a product-focused environmentExperience in DevOpsExperience working with Hexagonal Architecture and DDD