Requirements traceability
Applicable gematik requirements were translated into implementable behaviours, acceptance criteria, and a traceable verification scope.
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HealthcareInsuranceMobileQuality Assurance
German Statutory Health Insurer
Secure healthcare messaging across three platforms.
Building a secure TI-Messenger client for iOS, Android, and desktop on a shared Kotlin Multiplatform foundation, aligned with applicable gematik requirements.
Project context
Delivery window
Less than six months
Industry
German Healthcare
Platforms
iOS · Android · Desktop
Germany’s healthcare system uses the Telematikinfrastruktur to support secure digital communication between participants in care.
TI-Messenger products operate in a regulated environment where interoperability, identity, data protection, and predictable client behaviour are defined through gematik specifications.
The end client remains confidential. MTD can identify the sector and implementation scope, but not publish the insurer’s name or a client testimonial.
The challenge
The programme needed a client-specific TI-Messenger experience across iOS, Android, and desktop without rebuilding the complete messaging domain separately for every platform. The application also had to translate detailed gematik requirements into consistent product behaviour while preserving the platform-specific experience where it mattered.
How we moved
- 01Mapped applicable gematik requirements to delivery scope, acceptance criteria, and verification activities
- 02Established Kotlin Multiplatform as the shared base layer for messaging and domain behaviour
- 03Integrated the Matrix-based TI-Messenger SDK and adapted it to the insurer’s application needs
- 04Built a custom iOS interface while sharing most UI implementation across Android and desktop
- 05Verified secure chat, trusted-device, session, notification, account, and preference workflows end to end
Delivery methodology
Shared logic. Platform judgement.
Shared-core architecture
Kotlin Multiplatform carried common messaging and domain logic so platform teams could reuse the core without forcing one interface everywhere.
Platform-aware experience
iOS received a custom user interface, while Android and desktop reused most of the same UI implementation where their interaction models aligned.
Continuous verification
Functional behaviour, security-sensitive flows, and cross-platform consistency were checked throughout implementation rather than deferred to the end.
The solution
A cross-platform TI-Messenger application with a shared Kotlin foundation and platform-aware interfaces. The delivered scope covered secure exchange of text, images, videos, and documents; message editing, reactions, replies, and reporting; trusted-device access to encrypted history; session controls; notifications; account management; and user preferences.
Business outcomes
3
client platforms delivered
Counted as iOS, Android, and desktop application targets within the delivered scope.
<6 mo
end-to-end implementation window
Measured from implementation start through delivery of the complete solution described in this case study.
1
shared Kotlin foundation
One Kotlin Multiplatform base layer carried shared messaging and domain behaviour across the platform targets.
20M
insured-person population in the intended service scope
A design target for the addressable insured population, alongside participating doctors—not a claim of registered or active users.
From requirement to delivered state
Application coverage
Starting point
A client-specific, cross-platform TI-Messenger application was not yet implemented.
Delivered state
Working client experiences for iOS, Android, and desktop.
Cross-platform architecture
Starting point
Core messaging behaviour needed a maintainable implementation strategy across platform targets.
Delivered state
Shared Kotlin Multiplatform logic with platform-specific implementation where needed.
User-interface delivery
Starting point
The product experience needed to respect different platform expectations.
Delivered state
A custom iOS interface and a largely shared interface across Android and desktop.
Requirements coverage
Starting point
Detailed gematik requirements had to be converted into application behaviour and verification criteria.
Delivered state
Applicable specified requirements implemented and checked within the delivery scope.
Capabilities
Technology
Kotlin MultiplatformTI-Messenger SDKMatrix protocolEnd-to-end encrypted messagingNative iOS UIShared Android and desktop UI
Evidence & disclosure
The insurer’s identity is withheld under client confidentiality. Sector, architecture, delivery method, technology, and scope are published with permission to describe MTD’s work without identifying the organisation.
Published 24 August 2026
Public technical references