Senior Java/Kotlin Developer

About Unlimit

 

Unlimit is the global fintech powerhouse behind the world’s largest proprietary payments infrastructure.

Founded in 2009, Unlimit operates across 17 global offices with 700+ experts, seamlessly integrating 1,000+ payment methods into a single platform. From London to São Paulo, we empower businesses to scale across borders with a unified suite of financial tools — including payment processing, alternative payment methods, multicurrency business accounts, card issuing, banking-as-a-service, and crypto on- and off-ramps.

Our mission is to break down financial barriers and enable seamless money movement across borders. We give forward-thinking businesses the tools to accept, send, and manage payments effortlessly, wherever they operate.

We’re looking for a Senior Java/Kotlin Developer to design and implement modern, scalable backend services that power Unlimit’s global financial platform.

You’ll play a key role in building and evolving our payments and banking infrastructure — designing resilient microservices, integrating with global partners, and contributing to an architecture that’s fast, reliable, and ready for the future of AI-driven financial technology.

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What You’ll Be Doing

• At Unlimit, we are building the technology backbone for next-generation financial solutions—spanning payments, Banking-as-a-Service, crypto, and AI-driven services. As a Java/ Kotlin Developer, you will design and develop resilient microservices and APIs that enable these innovations to operate securely and at scale. You’ll build new integrations with external partners and payment systems, working across a distributed environment to ensure performance, reliability, and seamless operation. You will collaborate with other developers, DevOps, and data teams to optimize system design, automate delivery, and support continuous improvement across our engineering organization. Your work won’t stop at writing code—you’ll participate in design discussions, code reviews, and performance tuning sessions, constantly striving to make our systems more efficient and scalable. You’ll be encouraged to explore new frameworks and tools, helping keep our platform ahead of the curve and ready for AI-enabled automation, analytics, and decision-making. This role is ideal for someone who enjoys solving complex problems, takes ownership, and thrives in a fast-paced, collaborative environment where innovation and craftsmanship go hand in hand.

Qualifications You Will Bring

• 4+ years of hands-on experience with Java (Spring, Spring Boot) or Kotlin in production environments.
• Proven experience designing, developing, and debugging RESTful web services and microservices in distributed systems.
• Confident knowledge of Git, Gradle, and common development and delivery tooling used in modern backend engineering (CI/CD, artifact repositories, monitoring tools).
• Solid understanding of software architecture, performance optimization, and scalability in cloud environments.
• Ability to troubleshoot complex issues and deliver elegant, maintainable solutions under time pressure.
• Initiative, curiosity, and ownership—comfortable exploring new technologies and driving innovation from within.
• Strong English communication skills, with the ability to collaborate effectively in cross-functional and international teams.      
• Strong AI-driven mindset and curiosity about emerging AI technologies.
• Hands-on experience using AI tools (e.g., LLMs, automation frameworks, AI-assisted development tools) to enhance productivity or system performance.

Nice to have:

• Experience in fintech, payments, or banking systems.
• Experience working with AWS services and infrastructure.
• Familiarity with containerized deployments (Docker, Kubernetes) and CI/CD pipelines.
• Exposure to AI-enabled systems or interest in integrating intelligence into applications.
• Background in event-driven architectures and message-based systems (Kafka, RabbitMQ).

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Join Unlimit Team now!

Unlimit is an equal opportunity employer. We believe passionately that employing a diverse workforce is central to our success. We make recruiting decisions based on your experience and skills. We welcome applications from all members of society irrespective of age, sex, disability, sexual orientation, race, religion or belief.