Full Stack Developer

Circle K Business Centre is seeking a Full Stack Developer to join the Retail and Digital Channels Development team. The role involves designing and implementing backend services and frontend applications for POS systems and cloud integration, working with Java, Spring, and JavaScript frameworks in an agile, multinational environment.

• Design and implement backend services for the global retail sales platform — domain services, REST/SOAP interfaces, message-driven integrations and data access layers
• Design and implement POS functionality using our proprietary development stack (Spring-based backend, custom DSL)
• Build and maintain custom extensions, integrations and configurations within the retail platform, avoiding changes to the POS core wherever possible
• Work with Data Containers, Master Data distribution and the Service API layer for POS integrations
• Implement and configure business processes: checkout flows, payment handling, barcode processing rules and loyalty engine integrations
• Contribute to localization and fiscalisation of POS solutions for different European markets
• Ensure changes follow proper lifecycle management: versioning, environment promotion (DEV → TEST → PROD)
• Develop custom web applications that are launched on the POS and run inside its dedicated embedded browser (JxBrowser/Chromium), integrated through the App Enablement Framework and its JavaScript API bridge
• Build the backend endpoints and integration flows those applications depend on, so that a feature is delivered end to end by one team
• Extend and maintain our enterprise frontend applications (Employee Hub, Launchpad)
• Work within the constraints of in-store hardware and checkout ergonomics — touch input, limited screen real estate, operator speed

• 4+ years' Java development experience (Java 8+, ideally Java 11+), including JUnit, JPA/Hibernate, JAX-RS/JAX-WS
• Solid Spring Framework experience across both worlds: modern Spring (Boot, Data, Cloud) and legacy Spring with XML/Java-based configuration, annotations and custom extensions
• Experience with REST and SOAP interfaces, API documentation (Swagger/OpenAPI) and microservice communication patterns
• Experience with relational databases (PostgreSQL, SQL, data modelling)
• Working knowledge of at least one modern JavaScript framework (React, Angular, Vue.js, SAP UI5 or similar) and TypeScript — enough to build and maintain production frontend applications
• Practical knowledge of Git, CI/CD and version control workflows (Jenkins, Sonar, Gradle)
• Understanding of POS systems, retail checkout flows and payment processing concepts
• Knowledge and practice in applying design patterns and principles; basics of Domain Driven Design
• Experience with agile software development methodologies (SCRUM)
• Fluent English and Polish — B2/C1 minimum
• Prior experience with OmniPOS / CLOUD4RETAIL platform
• Knowledge of fiscalisation requirements in European markets (Poland, Baltic states, Nordics)
• Experience with JxBrowser or other Chromium-based embedded browser engines
• Familiarity with Storemanager or similar retail configuration tooling
• Experience in loyalty systems integration, mobile payment flows or self-checkout solutions
• Experience with NoSQL (MongoDB, Cosmos DB) and Redis
• Experience with containerisation and orchestration (Docker, Kubernetes)
• Experience with cloud environments, Azure preferred
• Knowledge of TDD/BDD approaches (Spock, Mockito, Cucumber)
• Understanding of edge computing architectures (central ↔ edge ↔ checkout)
• Degree in Computer Science or Engineering

• Contract of employment
• Annual bonus
• Private medical care
• Cafeteria Platform/Multisport
• English lessons subsidized by the company
• Group insurance
• Attractive discounts for products and services at our stations
• Employee stock purchase plan
• Employee Assistance Program (Lyra)
• Two additional days off (Good Friday, Friday after Corpus Christi) – with the possibility of exchanging for other holidays
• Employee Referral Bonus Program
• Modern and convenient office that you can virtually visit here - https://goo.gl/maps/CLteHfYcdYMbdESq6
• Trainings & possibility to develop skills in a wide international environment