Java backend developer

Worldline; Warszawa; Hybrid; PLN 240,000 - 360,000; Full time

Benefits offered by this job

Private medical & life insurance

Public transportation allowance

Annual bonus

Job summary

Worldline in Warsaw, Poland is seeking an experienced Senior Java Backend Developer for the Risk Technology Services team. You will drive end-to-end ownership from API design to cloud infrastructure, shaping resilient services and delivery pipelines.

You’ll mentor peers and influence architectural choices in a globally distributed context. The role demands hands-on development, collaboration, and a platform mindset to deliver secure, scalable solutions in a modern cloud environment.

Qualifications

• 4+ years of professional Java development.
• Strong Java, OOP (and some functional) programming mindset.
• Deep Spring Boot and Spring ecosystem experience, incl. Spring Security/OAuth2.
• SQL and relational DB experience (PostgreSQL), schema design and optimization.
• Experience designing RESTful APIs and distributed services.
• Containers (Docker) and CI/CD pipelines (Jenkins, GitLab CI).
• Automated testing at unit and integration levels (JUnit, Testcontainers).
• Knowledge of architecture patterns (clean/hexagonal, DDD) and secure coding.
• English communication skills; ability to lead in Agile and mentor peers.

Responsibilities

• Collaborate with cross-functional teams to deliver features and services.
• Own architecture decisions: service boundaries, APIs, data models.
• Design schemas and manage migrations with Flyway/Liquibase.
• Build RESTful APIs and asynchronous integrations between services.
• Apply resilience patterns and champion test-driven development.
• Contribute to CI/CD, containerization, cloud infra and observability.
• Diagnose complex issues, lead incident investigations, and mentor others.
• Review code, uphold coding standards and security practices.

Skills

Java

Spring Boot

Spring Framework

Spring Security/OAuth2

REST APIs

SQL PostgreSQL

Docker

CI/CD

Testcontainers

OpenTelemetry

DDD/Hexagonal architecture

AWS

Git/GitHub

Terraform/CloudFormation

Jenkins/GitLab CI

Java ecosystem knowledge

Tools

Flyway

Liquibase

OpenAPI/Spring REST Docs

MinIO / cloud storage emulation

Datadog / OpenTelemetry

Terraform / CloudFormation

Job description

Worldline helps businesses of all shapes and sizes to accelerate their growth journey - quickly, simply, and securely. We are the innovators at the heart of the payments technology industry, shaping how the world pays and gets paid. Our technology powers the growth of millions of businesses across 5 continents. And just as we help our customers accelerate their business, we are committed to helping our people accelerate their careers. Together, we shape the evolution.

The opportunity

As a Senior Java Backend Developer at Risk Technology Services technical team, you'll go beyond writing high-quality code – you will engage actively in architectural discussions, contribute to technical decisions, and take genuine end-to-end ownership of what you ship. From service design and API development to cloud infrastructure and delivery pipelines, you'll bring strong engineering fundamentals and a platform mindset to a team that builds and operates software together. We're looking for someone who is hands-on, collaborative, and makes the people around them better simply by doing great work.

Day-to-day responsibilities

• Work closely with a cross functional team on the delivery of new features and services; setting the standard and technical direction for Risk tech service.
• Own architecture and design decisions: service boundaries, APIs, cross-service contracts, and data models - balancing simplicity, reliability, security, and maintainability.
• Design database schemas and manage evolution through versioned migrations.
• Design and build RESTful APIs and asynchronous/event-driven integrations between services.
• Apply resilience patterns (retries, idempotency, circuit breakers) and champion test-driven development with strong coverage.
• Own delivery: contribute to CI/CD pipelines, containerization, cloud infrastructure, and observability.
• Diagnose complex issues across services and infrastructure; lead incident investigation and resolution.
• Run and participate in code reviews; mentor mid-level and junior developers.
• Establish and uphold coding standards, security practices, and design principles across the team.

Who are we looking for

Technical knowledge requirements
Depth in several areas is expected; breadth across the rest. AWS is our primary cloud platform – equivalent hands‑on experience on GCP or Azure is accepted.

- Language & frameworks: Java (LTS), Spring Boot/Spring Framework, Spring Security (OAuth2/JWT)

- Schema migrations: Flyway
- Cloud & infrastructure: AWS (or GCP/Azure), Docker, IaC (Terraform/CloudFormation)
- Cloud services (AWS or GCP/Azure equivalents):
- Containers: ECS + ECR
- Object storage: S3 (≈ Cloud Storage/Blob Storage)
- Messaging: SQS (≈ Pub/Sub/Service Bus) or any similar messaging system
- Database: RDS PostgreSQL (≈ Cloud SQL/Azure Database for PostgreSQL)
- Infrastructure & networking: CloudFormation, IAM, VPC/Security Groups
- Build & CI/CD: Maven or Gradle, Jenkins (or GitLab CI)
- Testing: JUnit, AssertJ, Testcontainers, local cloud emulation (e.g. MinIO, ElasticMQ)
- Observability: distributed tracing, metrics, logging (e.g. OpenTelemetry, X-Ray, CloudWatch, Datadog)
- Version control: Git (GitHub/GitLab)
- AI-assisted development: AI coding assistants/CLI tools (Claude Code, GitHub Copilot)

Requirements (must-have)
- 4+ years of professional Java development
- Modern Java (latest LTS) and a mindset of keeping up with the newest stable features and tooling
- Proficiency in Java and OOP (ideally also functional) programming
- Strong Spring Boot and Spring ecosystem experience, incl. Spring Security/OAuth2
- Solid SQL and relational DB experience (e.g. PostgreSQL), incl. schema design and query optimization
- Schema migration tools (e.g. Flyway, Liquibase)
- Designing and building RESTful APIs and integrating distributed services
- Containers (e.g. Docker) and CI/CD pipelines (e.g. Jenkins, GitLab CI)
- Strong automated testing – unit and integration (e.g. JUnit, Testcontainers)
- Solid grasp of software architecture and design patterns (e.g. clean/hexagonal architecture, DDD)
- Understanding of secure coding, resilience and observability in production
- Confident use of Git and modern branching/merging workflows
- Ability to lead in an Agile environment and mentor other developers
- AI-assisted development – AI coding assistants/CLI tools; awareness of prompting, context windows and token cost
- Designing and implementing async/event-driven integrations correctly (messaging, idempotent consumers, ordering, retries/dead‑letter handling, eventual consistency), even where used only occasionally
- Strong written and spoken English; able to articulate technical decisions, raise concerns and collaborate in a distributed team

Nice-to-have
Technical
- Hands-on experience with a cloud platform (AWS preferred; GCP/Azure accepted)
- IaC ownership (Terraform, CloudFormation) with awareness of cloud cost and scaling
- Distributed tracing and observability at scale (OpenTelemetry, Datadog or equivalent)
- Spring Data JDBC and API documentation tooling (OpenAPI/Spring REST Docs)
- Cloud certification (e.g. AWS Certified Developer – Associate, Solutions Architect, or GCP/Azure equivalent)
Professional
- Introducing standards, tooling or process improvements across teams
- Comfortable working in distributed/international environments
- Sound technical judgment and pragmatism – knows when not to add complexity
- Ownership mindset and continuous-improvement attitude

At Worldline you’ll get the chance to be at the heart of the global payments technology industry and shape how the world pays and gets paid. On top of that, you will also:

• Private medical & life insurance
• Public transportation allowance
• Annual bonus

Pursuant to the Article 24 sec. 6 of the Act of 14 June 2024 on the protection of whistleblowers, we inform you that Worldline Financial Services (Europe) S.A., a joint-stock company, Branch in Poland (hereinafter referred to as Worldline) is governed by the Regulations on the receipt of internal reports and taking follow-up actions (hereinafter referred to as the Regulations).

Shape the evolution

We are on an exciting journey towards the next frontiers of payments technology, and we look for big thinkers, people with passion, can-do attitude and a hunger to learn and grow. Here you'll work with ambitious colleagues from around the world, take on unique challenges as a team, and make a real impact on the society. With an empowering culture, strong technology and extensive training opportunities, we help you accelerate your career - wherever you decide to go. Join our global team of 18,000 innovators and shape a tomorrow that is yours to own.

Learn more about life at Worldline at jobs.worldline.com

We are proud to be an Equal Opportunity employer. We do not discriminate based upon race, religion, color, national origin, sex, sexual orientation, gender identity, gender expression, age, status as an individual with a disability, or any applicable legally protected characteristics.

Job Location: Poland - Warsaw, Poland - Remote