Senior Java Developer

Sigma Software

Posted about 1 month ago

About this role

Full Time Senior Senior Java Developer in AI at Sigma Software in Warsaw, Masovian Voivodeship, Poland. Apply directly through the link below.

At a glance

Work mode: Office
Employment: Full Time
Location: Warsaw, Masovian Voivodeship, Poland
Experience: Senior · 5+ years

Core stack

High Availability
Cross-functional
Microservices
Architecture
Spring Boot
Performance
Distributed
Scalability
Innovation
Compliance
Security
Payment
Kotlin
Design
MySQL
Kafka
Java

Quick answers

What skills are required?
High Availability, Cross-functional, Microservices, Architecture, Spring Boot, Performance, Distributed, Scalability, Innovation, Compliance, and more.

Sigma Software is hiring for this role. Visit career page

Warsaw, Poland

Company Description

Are you ready to take ownership of mission-critical backend systems in a high-load, transaction-heavy environment? We are looking for a Senior Java Developer to join our Payments Domain team in Warsaw.

This is a hybrid role with 3 days per week in the office, giving you the perfect balance between collaboration and flexibility. At Sigma Software, we value engineering excellence, multicultural teamwork, and delivering secure, high-performance solutions.

Why join us? You’ll work on a platform processing millions of transactions daily, contribute to architectural decisions, and be part of a company where innovation and ownership are encouraged.

CUSTOMER

Our customer is a well-established international company in the iGaming industry, known for its engineering-driven culture and multicultural team distributed across multiple countries. Operating multiple brands across various markets, the company delivers secure, high-performance digital platforms recognized for reliability and scalability.

PROJECT

You will be part of the Payments Domain team, responsible for developing and maintaining a large-scale payments platform built on modern microservices architecture. The platform processes millions of secure transactions daily, supporting multiple brands and geographies. The work focuses on scalability, reliability, and performance in a high-load environment, covering everything from integration with payment providers to transaction monitoring and compliance.

Job Description

Design, develop, and maintain backend services for the payments platform using Java and Spring Boot
Ensure high availability, scalability, and performance of transaction processing systems
Collaborate with cross-functional teams to define technical requirements and deliver solutions end-to-end
Implement integrations with payment service providers and internal systems
Participate in architectural discussions and contribute to system evolution in a microservices environment
Monitor, troubleshoot, and optimize services in production
Ensure compliance with security, regulatory, and operational standards
Drive continuous improvement in code quality, testing, and deployment practices

Qualifications

5+ years of commercial experience with Java and Spring Boot
Strong experience with MySQL and Kafka
Proven track record working with microservices architecture in high-traffic, high-load systems
Experience developing high-performance backend solutions for transaction-heavy platforms
Ownership mindset with ability to deliver services end-to-end
Excellent communication skills in English (C1 level), both written and verbal
Experience with Kotlin