Senior Backend Developer

Paymenttools is on a mission to transform the payment landscape for retailers in Europe. With more than 4,4 billion visitors per year in our more than 15,000 REWE Group stores and travel agencies in 21 countries we know exactly what consumers and merchants need when exchanging goods for money. We strongly believe in making payments seamless and invisible, linking them with value added services within the framework of a reliable identity service. Our mantra: #wesolvepayn. We blend cutting-edge technology with stringent security to protect sensitive payment data while nurturing innovation in a cloud-native tech environment.

We're looking for a Senior Backend Engineer to join one of our agile scrum teams. You will help build and evolve core payment capabilities—from secure data handling and merchant onboarding to scalable services powering new payment methods. If you enjoy working end-to-end on products that matter at a massive scale, and you like turning complex problems into elegant, reliable systems, you'll feel right at home with us.

Your tasks

• Design, develop, and maintain backend services that are secure, scalable, and compliant—supporting millions of payment transactions and merchant configurations.
• Build and evolve microservices in a modern cloud environment (we use Google Cloud Platform), ensuring reliability and performance at scale.
• Own features end-to-end: from technical design and implementation to deployment, monitoring, and continuous improvement (you build it, you run it).
• Develop and enhance customer-facing APIs to provide robust, well-documented integration points for our partners and internal consumers.
• Strengthen platform architecture with a focus on security, observability, and maintainability.
• Contribute to DevOps practices: CI/CD pipelines, monitoring, and infrastructure best practices.
• Collaborate closely with engineers, product, and stakeholders to deliver solutions that improve the payment experience for merchants and end customers.
• Keep learning, share knowledge, and help raise the engineering bar across the company.

Your experience

• 7+ years of professional backend engineering experience in a relevant role, ideally in high-throughput or regulated domains.
• Strong proficiency with JVM technologies such as Java and/or Kotlin, plus Spring / Spring Boot and ORM frameworks.
• Solid understanding of microservice architectures, distributed systems, and API design.
• Hands-on cloud experience (GCP or AWS), including containerization and orchestration with Docker/Kubernetes.
• Experience with CI/CD tooling and operational excellence: monitoring, alerting, and performance tuning using tools like Prometheus and Grafana.
• Strong background in security topics such as authentication/authorisation, encryption/decryption, and secure data storage.
• Confidence working with relational databases (schema design, transactions, query optimisation) and familiarity with NoSQL is a plus.
• Fluent English (working language). German skills are a plus.
• Experience with frontend development (TypeScript, React) is a plus—especially if you enjoy collaborating across the stack.
• Payment industry knowledge (PCI-DSS, tokenisation, compliance, fraud/AML concepts) and concurrency management are advantages—but not required.

Our Benefits

• Deutschland ticket, subsidized subscription
• 1.000 euro annual learning and development budget + internal training platforms
• Discounts on travel, fashion, technology, and more through our corporate benefits
• REWE discount card for discounts for REWE group retailers
• JobRad, affordable bicycle leasing
• Company pension plan
• Insurance Services

Perks of working with us

• We work in a hybrid environment
• Flexible working hours that fit your workflow, your time matters
• Language courses (English and German)
• Responsibility from day one
• Work with modern and agile software such as Google Workspace, Slack, Asana, Jira, Lattice, Miro and Confluence
• Company events including Hackathons and Company Days (ask us more about these)

We are looking forward to getting to know you - so, even if you feel that you don't quite meet all the requirements, but the position still excites you and you think you would love to work with us, please reach out We would still love to hear from you. We explicitly encourage applicants within groups that are underrepresented in tech spaces as of today. We value all kinds of backgrounds and walks of life.