I build and modernize large-scale Swift codebases. Currently working on Germany's electronic patient record (ePA) — a white-label iOS app serving 15+ health insurers, developed with 40+ engineers.
IBM ePA — electronic patient recordcurrentWorked on Germany's first electronic health record: one IBM white-label codebase powering the apps of 15+ statutory health insurers. In a project of 40+ engineers, my focus was mostly on architecture, authentication, making the app accessible, reducing tech-debt, bug fixing, SwiftUI adoption, and SBOM generation — plus interfacing with KMP for business logic.
BARMER eCareAward-winning patient-record app for one of Germany's largest insurers. In a team of six, I drove architectural improvements, ported the app from UIKit to SwiftUI, and added dark-mode support across the whole app.
Public-transport app platform (Siemens subsidiary)White-label app powering 70 individually configurable transit apps from one codebase. In a team of 15 iOS engineers, we built features in TCA, SwiftUI, and Combine; migrated legacy Objective-C to Swift; split features into modular CocoaPods assembled via dependency injection; unit + snapshot tests with GitLab CI and fastlane delivery.
Mercedes-Benz Advanced ControlCamper-van smart-home app (roof, awning, heating, lights, ...) talking to the vehicle over BLE. In a team of 4, we implemented ECDH key exchange, AES-CCM encryption, and a fully dynamic UI generated from a JSON config parsed over Bluetooth. For part of the project I was the lead iOS engineer and Scrum Master.
BMW Motorrad Connected & BMW One ConnectedMotorcycle navigation optimized for riders — HERE/TomTom routing, head-unit communication, audio guidance — plus feature work on BMW's connected-car app in a 30+ developer project.
Ubermind Track — indie appSolo side project, end to end: idea, design, architecture, development, TestFlight betas and App Store release. An app for tracking personal self-experiments.
HieroQuest — master's thesis at TUM: an educational game teaching Egyptian hieroglyphs, incl. an experimental learning study (Unity 3D).
LeadApp, Weptun — lead developer of an iOS lead-management client with business-card scanning.
KRI SWOOP — stroke-patient workflow tracking with BLE beacons at hospital Rechts der Isar; team coach & Scrum Master.
iWash — washing-label image recognition (OpenCV) and NFC for B/S/H; lead developer in a team of 7.
Modernising grown codebases without stopping feature work — UIKit → SwiftUI, refactoring, tech-debt strategy.
Health and automotive: sensitive data, authentication, accessibility and security requirements as daily business.
BLE protocol design, applied cryptography, state machines, config-driven UI — the parts most app developers avoid.
Comfortable in 40+ engineer codebases; experience as Scrum Master, team coach and onboarding mentor.
Agentic coding tools (Claude Code, Cursor) in the daily loop — LLM-accelerated refactoring, tests and docs, always gated by a senior engineer's review.
Shipped a solo indie app from idea to App Store release — comfortable owning products, not just tickets.
"Dennis covers a remarkable range — from the architecture of our white-label app through complete UI features and thoughtful accessibility to CI automation that made our whole workflow more efficient. […] You can rely on Dennis 100%. When problems come up he doesn't go quiet — he communicates openly and works toward a solution. Any team looking for an iOS developer who delivers independently and takes ownership is extremely well served with him."
I write about productivity systems: author of Scale-Smart Productivity and the blog Fractal Productivity.
Open to remote roles with EU/US overlap. German citizen — authorized to work across the EU, no visa sponsorship required. German (native) · English (fluent).
dennisnehrenheim90 [at] gmail [dot] com