Software Engineer III – Backend Java | E-Commerce Platform

Location: Warsaw, PolandWork model: Hybrid – minimum 3 days per week from the Warsaw officeTechnology: Java 25, Spring Boot, Distributed SystemsIndustry: Software Development / SaaSAbout the roleWe are looking for an experienced Software Engineer III – Backend Java to join an international technology company and work on a large-scale E-Commerce Platform.The platform supports critical purchasing, subscription and account management processes used by customers across multiple international markets.

The team builds and develops systems that enable customers to purchase, adopt and manage digital products and services through self-service experiences.This is a business-critical part of the product, directly supporting revenue generation and international growth. Scalability, reliability and availability are therefore key engineering priorities.The role combines hands-on backend development with technical design, system architecture, problem solving and collaboration with Product and Engineering teams.What you'll be working onThe team is currently focused on expanding the capabilities of the E-Commerce platform while modernizing its technology stack.You will work on backend services supporting purchasing and subscription processes, helping improve platform performance, scalability and developer productivity.You will also have the opportunity to influence technical decisions and contribute to solutions that have a direct impact on both the product and the business.What you'll doDevelop high-quality, scalable and reliable backend services using modern technologies.Build and evolve highly scalable distributed systems.Write clean, efficient and maintainable code following engineering best practices.Contribute to technical design and architecture decisions.Take ownership of solutions from technical investigation through implementation and production deployment.Work closely with Product Managers and cross-functional engineering teams.Participate in code reviews and provide constructive technical feedback.Troubleshoot and debug software and production issues.Contribute to automated testing and overall platform quality.Participate in Agile/Scrum ceremonies, including sprint planning, stand-ups and retrospectives.Support and mentor other engineers within the team.Participate in the team's production on-call rotation.What we're looking for4+ years of professional software development experience.Strong commercial experience with Java.Experience with Java 25 and Spring Boot.Hands-on experience building highly scalable distributed systems.Strong understanding of algorithms, data structures and software design principles.Good understanding of scalability, observability and production reliability.Solid experience with automated testing principles and frameworks.Strong problem-solving skills and ability to independently investigate complex technical challenges.Ability to take ownership of technical solutions and drive them through to completion.Experience supporting or mentoring other engineers.Professional working proficiency in English.Nice to havePrevious experience in E-Commerce, FinTech, payments, subscriptions or transactional systems.Experience leading cross-functional technical projects.Experience working with distributed engineering teams across different time zones.Previous experience with PHP.Interest in applied AI and modern AI-assisted software development, including experimenting with AI agents, tools, prompt engineering or model integrations.How you'll spend your timeApproximately:45% – Coding30% – Technical design & investigation15% – Meetings and collaboration10% – Developer support & mentoring5% – DocumentationEngineering environmentMethodology: Agile / ScrumIssue tracking: JiraKnowledge base: ConfluenceVersion control & code reviews: GitHubWorking modelThis role is based in Warsaw and follows a hybrid working model.The team works from the Warsaw office a minimum of 3 days per week, so we are looking for candidates who are comfortable combining remote work with regular in-person collaboration.