Full Stack Developer

Circle K Stores Inc.; Warszawa; On-site; PLN 180,000 - 280,000; Full time

Benefits offered by this job

Annual bonus

Private medical care

Cafeteria

Platform/Multisport

English lessons

Group insurance

Employee stock purchase plan

Employee Assistance Program

Job summary

Circle K Global Development is seeking a Full Stack Developer to join the Retail and Digital Channels Development Section. You will work on cloud-based integration and POS systems in stores, spanning backend and embedded browser apps.

Role covers platform/backend and app enablement sides with a focus on integrating checkout, payment, loyalty, and localization across European markets. English and Polish proficiency required; Warsaw-based team with modern tools.

Qualifications

• 4+ years of Java development experience (Java 8+, ideally 11+).
• Solid Spring Framework experience across modern and legacy Spring.
• REST and SOAP interfaces, API documentation (Swagger/OpenAPI).
• Relational databases experience (PostgreSQL, SQL).
• Experience with modern JavaScript frameworks and TypeScript.

Responsibilities

• Design and implement backend services for the global retail sales platform.
• Design and implement POS functionality using the proprietary stack.
• Build and maintain extensions and configurations within the retail platform.
• Work with Data Containers, Master Data distribution, and Service API layer for POS integrations.
• Implement business processes: checkout flows, payments, barcode processing, loyalty integrations.
• Contribute to localization and fiscalisation of POS solutions for Europe.
• Ensure lifecycle management: DEV → TEST → PROD.

Skills

Java development

Spring Framework

REST/SOAP

PostgreSQL

JavaScript framework

Git CI/CD

POS systems knowledge

Design patterns

SCRUM

English & Polish

Education

Degree in Computer Science or Engineering

Tools

JxBrowser

Docker

Kubernetes

Git

Gradle

Jenkins

Sonar

Job description

What you will be working on

We are looking for a Full Stack Developer to join the Retail and Digital Channels Development Section at Circle K Global Development. The role sits on the boundary between our cloud-based integration platform and the POS System running in our stores, and covers both sides of that boundary.

On the platform and backend side you will:

• 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)

On the App Enablement side you will:

• 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

You will collaborate with a Technical Product Owner, Solution Architects, QA Engineers, DevOps and numerous skilled developers in an agile, multinational environment.

Requirements

Must have:

• 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

Nice to have:

• 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

Technology Stack

• Backend (platform): Spring Boot, Spring Data, Spring Cloud, JPA/Hibernate, PostgreSQL, NoSQL (MongoDB, Cosmos DB), Redis, Azure cloud services
• Backend (POS): Spring Framework (legacy version with custom extensions, XML/Java-based configuration, no Spring Boot auto-configuration)
• Frontend: enterprise JavaScript framework applications (Employee Hub, Launchpad); React/Angular/Vue.js for custom POS apps
• Custom app integration: JxBrowser engine (Chromium 139.x) with JavaScript API bridge
• POS configuration: Storemanager, Menu Editor, Data Containers, Barcode Processor rules
• Integration: Service API, REST and SOAP interfaces, external loyalty and payment system connectors
• Tooling: Git, Gradle, Jenkins, Sonar, Docker, Kubernetes; Eclipse 2020 (required for the POS toolchain)

Working as a Developer at Circle K, you will operate within the following technology environment:

The listed stack above is fully representative of the environment you will be working in.

What do we offer?

• 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

When working with us you can depend upon it that you will not be judged on the grounds of race, national origin, gender, sexual orientation, disability, age, or other legally protected status. Oppositely – we believe that our diverse and inclusive culture helps us create an amazing atmosphere where everybody feels welcome.

Check who we are here: https://youtu.be/td-QGnNnvW0

Want to know even more about us? Take a look at our career page: https://workwithus.circlek.com/global/en/businesscentrewarsaw

Our mission at Circle K is to make people's lives a little easier every day. Our global family of 150,000 people in over 17,300 stores and 27 countries makes that possible for our millions of clients worldwide, which is why we are committed to helping them achieve their goals and grow with us. We set ourselves apart by our culture and values: in our people and their development, in serving others, what we've built and what we are striving to achieve. No matter where you come from or where you are heading in your career, there is a place for you to grow at Circle K. When you grow, we grow - together.