Senior Java Developer

Java

Emilii Plater 53, Warszawa

Sigma Software

Full-time

B2B

Senior

Hybrid

Tech stack

English

B2

Java

master

Spring Boot

master

MySQL

advanced

Kotlin

junior

Job description

We are seeking an experienced and visionary Senior Java Developer to play a key role in our software development initiatives. This project requires a developer who can plan, build, and deliver tasks as part of a team. As a solid group, we share responsibility for product delivery, including speed, efficiency, and quality. We also take full responsibility for the operational conditions of what we deliver.As an individual, you need to take ownership, drive initiatives forward, suggest improvements, and incorporate them in all areas.If this approach resonates with you, we invite you to join us!

Customer Our Customer owns one of the largest mobile gambling platforms, which has millions of users.

Project We work with a large company on a project using a startup approach. We use a state-of-the-art technology stack.

This new, proprietary, multi-brand platform will enable the Swedish operator to launch new brands under a collective name with a high level of flexibility and scalability.

Requirements

• 5+ years of experience with Java, including Java 8-17

• Proficiency in Spring Boot

• Experience with messaging systems such as Kafka and RabbitMQ

• Ability to design and implement Back-end services from scratch

• Solid understanding of relational databases, particularly MySQL

• Experience in building scalable, fault-tolerant systems and working with microservice architectures

Would be a plus

• Knowledge of Kotlin

Responsibilities

• Design, develop, and maintain Java-based applications

• Collaborate with cross-functional teams to define, design, and release new features

• Write clean, maintainable, and efficient code following best engineering practices

• Optimize application performance and troubleshoot issues

• Participate in code reviews to ensure high-quality software development

• Work with databases, APIs, and third-party integrations

• Stay up —to date with the latest Java technologies and frameworks

Published: 24.08.2025

Meet the company

Sigma Software

Sigma Software is a global software development company that enables enterprises, startups, and product houses to meet their technology needs through end-to-end delivery. We have been working since 2002, from all over the world.

Company profile

Office location