Senior Back-end Developer (JAVA)

About CUBE AI

CUBE AI is an Agentic Crime Prevention Platform, built at the intersection of agentic AI, cybersecurity, and fraud prevention. We serve the institutions on the front line of an exploding wave of AI-powered crime: banks, fintechs, and the platforms criminals cannot operate without. Our mission is ambitious: make the world a safer place. How we do it is the part we're most excited about, and the part we're happy to walk you through in a conversation rather than on the open internet.

Why this is the seat to take

This is a rare seat on a rocket ship. CUBE AI is early, exceptionally ambitious, and backed by some of the world's leading investors. Our founders have built and scaled startups to unicorn valuations and exits, and have run mega teams at mega companies. We are building the company that puts the institutions the modern economy runs on back on offense against AI-powered crime. The closest analogy is joining Palantir in its early days: a hard mission, a category we're defining rather than entering, and a small group of exceptional people compounding fast. If you want a comfortable role, this isn't it. If you want the defining chapter of your career, your best work alongside people who make you sharper, keep reading.

The role

We build the technology that detects and dismantles fraud and financial-crime campaigns in real time. As a Senior Backend Developer, you own the backend that powers it, and you help shape both the product and the architecture as we scale. This is a high-impact seat: you will work shoulder to shoulder with our data scientists, researchers, and engineers to turn frontier research into production systems that hold up under real-world load.

What you'll do

• Design, build, and scale the backend services behind CUBE AI's real-time fraud detection platform.
• Architect microservices with a hard bar for reliability, performance, and security.
• Turn our data scientists' and researchers' threat and fraud research into production-ready systems, in close partnership with them and the frontend team.
• Own features end to end: scoping, technical design, implementation, testing, deployment, and monitoring.
• Drive system-design discussions and the high-level architectural calls as the platform grows.

Our stack

• Java 21+ and Spring 3+
• MongoDB, Cloud SQL, BigQuery
• Google Cloud Platform
• REST APIs
• GitHub, with GitHub Actions for CI/CD
• AI-assisted, agentic development workflows (we build with AI, not around it)

What we're looking for

The bar (non-negotiable, every role):

• Extreme drive and passion for the work and the mission.
• Extreme ability to learn fast and operate with confidence in uncertainty.
• Extreme IQ and EQ. You raise the level of every room, and you lose an argument gracefully the moment someone's right.

For this role specifically:

• 4+ years building production systems with Java and Spring.
• 1+ years designing and running microservices.
• 1+ years on a major cloud stack (GCP or AWS).
• A degree in computer science, or equivalent hands-on mastery.
• Full application-lifecycle experience, with a track record of owning features from requirements to delivery.
• Excellent problem-solving and a genuine bar for detail.
• Fluent written and spoken English.

Bonus points

• CI/CD pipelines and containerization (Docker, Kubernetes).
• Building with NoSQL (MongoDB), SQL, and REST APIs.
• Big-data tooling: Apache Spark, Hadoop, Flink, or BigQuery.
• Testing frameworks and test automation.
• Sharp communication in a fast-moving, collaborative team.

How we work and who thrives here

Our core locations are Lithuania, London, and New York, and we consider remote-first candidates who can travel as needed for their role. We write more than we meet and move at warp speed. We're an AI-first company: every person here is amplified by a layer of AI agents, and we scale capability, not headcount. We don't buy services, we buy results. We're drivers, not passengers, so we hire people who go and do it without waiting for permission. We move fast, and we use judgment where it counts: we hold sensitive data and the trust of the institutions we protect, and we never cut corners there. Our culture runs on five virtues:

• A pedantic bar for quality. Work that is thorough, complete, and on time. We trust each other to deliver, fully.
• Radical ownership. See it, own it, fix it. Never defer a problem or an opportunity. You will never be reprimanded for taking initiative.
• Relentless energy and audacity. Building something exceptional demands enormous energy. We move forward with maximum drive.
• Automate everything. We scale the capability of our people, not the headcount. We always hunt the 10x multiplier, working alongside AI agents rather than piling on process.
• Have fun. We work with people we genuinely enjoy. It gets us through the hard stretches and keeps politics out.

What's in it for you

• Uncapped growth. In a company moving this fast, scope finds the people who can carry it. Ownership and title are earned in months, not years.
• Real self-realization. This is a place to become the most capable version of yourself, next to people operating at the top of their game.
• A direct line to senior product and engineering leaders, and a real say in where the product goes.
• You share in the outcome. When the company wins big, you win big.

What we offer

Join a rocket ship. Let's discuss compensation and the rest of the details on our call.

CUBE AI is an equal-opportunity employer. We welcome applicants of every background and will support any accommodations you need during the hiring process