Senior Software Developer – Kotlin, React and Microservices

Project overview

Application/Offer Deadline 27.10.2026, 09:00

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Project Framework Conditions

Project details

Frankfurt am Main; 100% remote

03.11.2026–31.10.2029; approx. 35.94 months

Scope: 691 PT of which 691 remote, 0 onsite = 100.00% remote

Utilization: Average approx. 4.42 days/week

Onshore: Germany

Language / Required Language Level: German – Native speaker

Role / Level: Developer / Senior; Number: up to 2

Conditions – Mandatory Information for Candidates:

For further processing of your application, this information is absolutely required: Please state your desired billing method and your hourly or daily rate, separated for remote and onsite. Also indicate whether travel expenses are included or will be charged separately. If charged separately, please state the amount or the basis for calculation.

1.1 Project/Process Context

An existing traffic control solution is being replaced. Cloud-based single-page applications in a microservice architecture will be further developed and operated, with a focus on UX, DDD, TDD, automated delivery/testing, and vulnerability management.

1.2 Project Structure

Agile DevOps teams, sometimes collaborating in a scaled manner, are responsible for development and operation; the client provides the Product Owner.

3.1. Scope

Independent, self-organized performance; orders in partial quantities/annual slices possible, no total call-off obligation.

4.1 Must-Have Requirements - 100% Mandatory to Fulfill

Proof M1–M5 each by experience level in years: Senior (> 5 years).

M1: Backend software development and application architecture with Kotlin in application design, e.g., Ports & Adapters or IODA.

M2: Frontend programming and architecture knowledge, at least with React.

M3: Practical experience with agile engineering practices.

M4: Cloud-based and containerized infrastructure in microservice architectures.

M5: Method and technology knowledge with DevOps.

4.2 Should-Have Requirements

S1 (30%): Proven practical experience with methods/tools of strategic and tactical Domain Driven Design; 2 references.

S2 (30%): Proven practical experience with Docs-First, e.g., Docs-as-Code or Spec Driven Development; 2 references.

S3 (20%): Practical monitoring with Prometheus; experience level Senior (> 5 years).

S4 (20%): Practical experience with Spring Boot; experience level Senior (> 5 years).

• Conditions / Billing Method (Hourly or Daily Rate)
• Hourly Rate Remote (EUR/hour) and Hourly Rate Onsite (EUR/hour)
• Or Daily Rate Remote (EUR/day) and Daily Rate Onsite (EUR/day)
• Travel Expenses
• Build and evolutionarily develop domain-oriented microservice architecture with Domain Driven Design; promote technical strategy, knowledge transfer, innovation, and standards.
• Implement/advise on architecture and implement/customize components, interfaces, modules, and databases using Spring, AWS, Messaging, and Kotlin; adhere to specified development standards.
• Optimize CI/CD pipelines with GitLab CI, Jenkins, Docker, and OpenShift/Kubernetes; ensure stable, as automated as possible operation, and improve architecture, processes, and tools.
• Start: 2026-11
• Duration: 36 Monate
• Remote: remote
• Location: Frankfurt am Main, Deutschland, DE
• Languages: German