Senior Backend Engineer (Fintech)

TL;DR

Senior Backend Engineer (Fintech): Designing, developing, and scaling backend systems that power Bonial's products with an accent on scalability, maintainability, and security. Focus on high-traffic, real-time, geo-located online applications and surrounding ecosystems.

Location: This role requires you to be on-site at our Berlin office for at least 80% of your weekly working hours. Must be located in or around Berlin and commute or be planning to relocate to Berlin or the surrounding area.

Salary: What is your annual salary expectation (gross) in Euro?

Company

Bonial is a digital advertising partner for offline businesses, supporting retailers in their marketing activities and helping them find a new audience.

What you will do

• Take end-to-end ownership of backend services, operating with autonomy and proactively addressing technical challenges.
• Play an active role in the development of high-traffic, real-time, geo-located online applications and surrounding ecosystems.
• Design and implement REST APIs on our AWS infrastructure, making use of AWS services for new components.
• Monitor our backend services in production environments to ensure high performance, scalability, and reliability.
• Explore technologies like AWS, PostgreSQL, ElasticSearch, Rest API.
• Build a system in the spirit of Agile methodologies (Scrum, Kanban)

Requirements

• Bachelor's or master's degree in computer science or similar qualifications.
• At least 5 years of experience building backend (for frontend) applications.
• Experience in Spring Boot and Java 21+.
• Strong experience in Node.js.
• Strong experience with hosting on AWS and making use of AWS’s services.
• Fluent in both spoken and written English.

Nice to have

• Experience with agentic tools (e.g., LLM agents, AI copilots and Claude Code).
• Hands-on experience with inter-service communication, fault-tolerant distributed systems, distributed caching mechanisms, and microservice architectures.
• Proficient with Docker and Kubernetes.
• Familiar with CI/CD pipelines and cloud platforms (preferably AWS) is highly desirable.
• Experience with PostgreSQL and Elasticsearch.

Culture & Benefits

• Currently, we have a policy that allows for up to 20% mobile work, which can be conducted from anywhere within Germany, and the option to work from abroad.
• Offer 28 days of holiday. You also get an extra day for each calendar year (up to 30 days) as well as other occasions (moving, working on a social project, etc).
• Provide visa sponsorship for those of you who are eager to join us from outside of Germany.
• Free lunch – whenever you’re at the office, we offer you different lunch options – and it’s all on us!
• Zen Rooms where employees can pray, relax or simply have some quiet time; fully equipped gym in the office, and a roof terrace for amazing social events.
• Wellbeing - giving you free access to nilo.health, a mental health app. In terms of physical training, also cover part of the subscription to the Urban Sports Club. Offer a corporate pension scheme so you don't have to worry about your retirement.