Senior Java Engineer

X-FLOW; Warszawa; On-site; PLN 180,000 - 280,000; Full time

Benefits offered by this job

Competitive salary

Flexible hours

Remote/office options

Career growth

Job summary

X-FLOW is a mobile game development company established in 2018. We gained recognition after the release of Happy Color, a popular digital coloring book and a successful ad-driven mobile app.

We are seeking a Senior Java Engineer to help build an analytical system processing petabytes of data. You will design scalable solutions with Java, Spring, and cloud technologies, balancing performance and complexity. Join a talented team with flexible hours and remote/office options.

Qualifications

• Strong knowledge of Java Core and memory model.

Responsibilities

• Contribute across the full lifecycle from design through implementation, debugging, and documentation.

Skills

Java Core & Memory Model

Spring Core/Data/MVC

SQL & Relational DBs

Multithreading

Software design principles

Tools

Gradle

Java 21+

Spring

k8s

RabbitMQ

AWS

GCP

Job description

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 take pride in our diverse and talented team and partners, spread across the UK, Cyprus, the Netherlands, and other regions worldwide.

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 will 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!

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