Freelance Backend Engineer - Kotlin (d/f/m)

About Mobimeo
Founded in 2018 by Deutsche Bahn AG, Mobimeo is shaping the future of everyday mobility through innovative, user-centered software solutions. Our mission is to make daily travel more efficient, simpler, and more sustainable. By leveraging cutting-edge technology, we integrate various modes of transportation and offer seamless digital experiences for travelers.

We work with a versatile tech stack, choosing the right tools for each job. Our backend services are built in Kotlin and Node.js, deployed in a Kubernetes environment running on AWS, with infrastructure defined via Terraform. Our agile teams practice test-driven development (TDD), continuous integration, and delivery using GitHub Actions.

We are currently looking for an experienced freelance backend engineer to support our payment systems team.

• Design, implement, and maintain scalable backend payment services, including support for multi-merchant marketplaces and invoice rendering.

• Build and manage integrations with third-party payment providers.

• Create and maintain interfaces for internal reporting and BI tools.

• Ensure high reliability and performance of services through proactive monitoring, incident handling, and operational support.

• Collaborate with cross-functional teams including frontend developers, DevOps, and product owners to deliver robust and cohesive features.

• Contribute to architecture discussions, conduct code reviews, and support continuous improvement of our engineering practices.

• Write and maintain unit and integration tests, ensuring long-term maintainability and scalability.

• Solid experience building scalable backend systems using: Kotlin, Spring Boot, Coroutines, JOOQ, Gradle, GitHub, Terraform, and AWS (EKS, RDS/PostgreSQL, S3, SNS/SQS, EventBridge).

• Strong knowledge of agile and clean coding principles, including TDD, pair programming, and CI/CD workflows.

• A proactive and independent work style with a "you build it, you run it" mentality.

• Strong analytical thinking and structured problem-solving.

• Excellent communication skills and a collaborative mindset.

• Previous experience in the payments domain (e.g., payment gateways, transaction flows, payment processing) is a strong plus.

• German language skills are a bonus but not mandatory.

• A freelance role within a motivated, agile team working on impactful projects in the mobility space.

• Flexible remote work setup with access to our offices in Berlin (EUREF-Campus, Schöneberg) and Hamburg (Hafencity) if desired.

• An opportunity to contribute to high-visibility products like DB Navigator and other Deutsche Bahn digital platforms.

• A dynamic environment where your expertise is valued and your input helps shape the future of urban mobility.