Senior Fullstack Software Engineer

Responsibilities

• At Ratepay, we develop next-generation payment solutions that power the checkout experience for some of Germany’s largest online retailers and marketplaces. As a Senior Software Engineer (m/f/d), you’ll play a key role in building secure, scalable, and user-friendly Buy Now, Pay Later products in a dynamic and fast-growing e-commerce sector
• You’ll join a collaborative, agile team dedicated to enabling seamless commercial and technical onboarding of merchants, marketplaces, and resellers. Our focus is on modern integrations, fast onboarding, and intuitive configuration—making it easy for merchants to go live quickly while also improving the experience for internal Ratepay teams involved in the process
• You take ownership of the design, development, operation and continuous improvement of our systems, ensuring high performance and stability
• You integrate internal and external APIs within a modern microservice architecture, with scalability and maintainability in mind
• You contribute actively to our agile software engineering process, collaborating with cross-functional teams including Product, Infrastructure, and Risk
• You mentor and support junior engineers, sharing knowledge and fostering a culture of learning and growth
• You bring in your ideas and technical experience to continuously challenge the status quo and drive innovation within the team
• You will be responsible for operational success of the teams services also being on call

Experience in fintech or risk-related systems would be an additional advantage

You have strong database knowledge, especially with PostgreSQL, and some familiarity with MongoDB or Redis is a plus

You understand RESTful APIs, OAuth2, event-driven architectures like Kafka, and microservices

Ideally, you are familiar with Kafka Streams and contract testing tools such as PACTYou have 6+ years of hands-on experience in Java backend development, with Kotlin being a plus

You are comfortable working in agile teams and embrace a Dev Ops mindset: “you build it, you run it.”You are proficient in Spring/Spring Boot, Docker, Git, and Maven You have experience building and deploying applications in cloud environments, preferably AWSYou possess solid frontend skills using Vue.js or another modern JavaScript framework