Software Developer Kotlin Multiplatform / TI-Messenger

Project overview

For one of Germany's leading statutory health insurance providers, based in Hamburg, we are looking for experienced software developers or Kotlin developers (m/f/d) for freelance support as part of a demanding Telematics Infrastructure project. The focus is on the development and provision of an independent Software Development Kit (SDK) for the Telematics Infrastructure Messenger (TI-M) within our client's native mobile application.

Responsibilities

• Independent conception, architecture, and implementation of the TI-M SDK based on Kotlin and Kotlin Multiplatform (KMP) for seamless integration into iOS and Android clients
• Complete software-side implementation and integration of the Matrix protocol according to the official gematik specifications
• Development and implementation of robust cryptographic methods for end-to-end encryption (especially Olm and MegOlm)
• Sustainable modularization, versioning, and maintenance of libraries and frameworks for smooth deployment to internal app development teams
• Independent status assessment, technical consulting, and implementation of measures for consolidating input channels in the data exchange (clearing) area, as well as preparation for expansion to BenAdmin and Scheduling
• Creation of reusable templates for customer orders and automation of data transfers from existing systems
• Detailed documentation of software architecture, APIs, and processes in Confluence, as well as technical instruction and knowledge transfer to internal team members for handover to regular operations

Requirements

• Completed degree in Computer Science, Business Informatics, Software Engineering, or a comparable IT qualification
• Many years of in-depth experience in software development with Kotlin and proven practical knowledge in Kotlin Multiplatform (KMP)
• Demonstrable, multi-year experience in the practical implementation and application of the Matrix protocol
• In-depth understanding and implementation experience with modern cryptographic methods (symmetric and asymmetric encryption, especially Olm and MegOlm)
• Comprehensive expertise in the development, interface design, and deployment of developer frameworks and SDKs
• Deep understanding of the Telematics Infrastructure (TI) in the German healthcare system, gematik specifications, and ideally prior experience in the TI-Messenger (TI-M) area
• Analytical, self-organized working style, strong consulting skills, and very good German language skills in speaking and writing

Project details

01.01.2027

up to * project days, extension option)

Primarily remote, partly on-site in Hamburg

Max.

€750.00 (remote and on-site)

• Start: 2027-01
• Duration: 6 Monate
• Remote: remote
• Location: Hamburg, Deutschland, DE
• Rate: 94-94 EUR/h
• Languages: German