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

Freelancer, Full-time · Berlin (EUREF-Campus 4-5, 10829), Hamburg (Am Sandtorkai 50, 20457)

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.

What to expect
  • 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.

What we are looking for
  • 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.

Why Mobimeo
  • 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.

Sounds good?
If you're a freelance backend engineer who’s passionate about tech and mobility—and ready to make a real impact—we’d love to hear from you.
About us

Mobimeo, founded by Deutsche Bahn AG in 2018, is shaping the future of everyday mobility with innovative and user-centered software solutions.  

Our vision: We make everyday mobility more efficient, simpler and accessible - for everyone. We use innovative technologies to connect different modes of transportation and offer travelers seamless, digital solutions for their daily journeys. With the needs of travelers always in mind, we create digital products that impress and inspire. Mobimeo's partners, such as transport companies, transit associations and mobility providers, save time and resources, allowing them to focus entirely on offering their users a smoth mobility experience.

Your application
Great to see that you are interested in joining our team. We want to get to know you better. Therefore, please complete the following form and add your LinkedIn profile and/or your CV to your application. In case you are experiencing problems send us an email to jobs@mobimeo.com.
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