Senior Java Engineer

Location: Warsaw, Mazowieckie, Poland X-FLOW is a mobile game development company established in 2018. We gained recognition after the release of Happy Color , the most popular digital coloring book and one of the most successful ad-driven mobile apps in the world. We're looking for a Senior Java Engineer to join our team and help us build an analytical system that processes petabytes of data. We expect candidates to have a deep understanding of the tools they use. If you can assess the complex problem, design and deliver a solution with attention to balance between performance and complexity — we might be looking for you. Technology stack: Gradle, Java 21+, Spring, k8s, RabbitMQ, Service-oriented infrastructure, AWS and GCP cloud platforms. Requirements: Strong understanding of Java Core, Memory Model, MultiThreading. Strong understanding of Spring Core, Data, MVC. Proficiency in SQL, solid understanding of Relational Databases. Solid understanding of software development principles. Solid understanding of data storage design principles. Nice to have: Experience writing and optimizing BigQuery queries. Experience with Spring Reactive stack, Spring Batch and AMPQ. Experience with Apache Camel. Experience with Graph DB like Neo4j. Responsibilities: You'll be involved across the full lifecycle of tasks — from solution design through implementation, debugging, and documentation. What We Offer: Competitive salary and benefits package. Opportunity to work with a talented and passionate team in a creative and dynamic environment. Flexible working hours and remote/office work options. Career growth and professional development opportunities. A fun and inclusive company culture that celebrates diversity and creativity. Join us and let’s create great content together! When you apply for this role, we process your personal data in accordance with our Candidate Privacy Notice ( https://xflowgames.com/candidate-privacy-notice ).