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
- 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
Skills Required
- 5+ years of commercial experience with Java and Spring Boot
- Strong experience with MySQL
- Strong experience with Kafka
- Proven track record 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
What We Do
Sigma Software Group, an award-winning and trusted IT partner, has been serving customers for over 21 years, providing comprehensive IT solutions to various businesses, ranging from startups to established software product houses. As one of Europe's substantial IT consultancies, it brings together a dedicated workforce of over 2,100 professionals in 40 offices across 19 countries. With a diverse client base, including more than 300 enterprises, including Fortune 500 stalwarts, Sigma Software Group is a preferred choice for developing solutions that help businesses create cutting-edge products while meeting their unique needs. Sigma Software Group operates as a dynamic ecosystem of tech companies, offering 25 ready-to-implement innovative products and 40+ value-added services. Furthermore, Sigma Software Group is committed to fostering innovation through initiatives such as the Sigma Software Labs business incubator, Sigma Software University, the SID Venture Partners VC Fund, UA Tech Network, Techosystem, the European Business Association, and other collaborative efforts. Since 2015, Sigma Software Group has consistently earned recognition on the IAOP's prestigious World's Top 100 Outsourcing list. The company's accomplishments have also been acknowledged by prominent global media outlets such as Forbes, CNBC, The Times, and Reuters
