About Demian Turner
Senior iOS & macOS Engineer | Open-Source Author | Team Leader
Demian Turner is a UK-based software engineer with over two decades of experience delivering high-performance desktop and mobile applications for Apple platforms. Until recently, he led a team of Swift developers at Global Relay, building compliant communications software trusted by the world’s largest financial institutions. A long-time advocate for open-source, Demian developed the Seagull PHP framework, a modular web development platform that has been downloaded over 40,000 times and used by developers around the world.
Professional Snapshot
| Last Role | Senior iOS/macOS Developer & Team Lead, Global Relay |
|---|---|
| Core Skills | Swift, SwiftUI, Objective-C, macOS/iOS SDKs, REST, CI/CD |
| Open Source | Creator & maintainer of Seagull Framework |
| Education | B.A, Concordia University, Montréal |
Career Highlights
Global Relay (2021 – 2025) – Senior iOS/macOS Developer & Team Lead
- Spearheaded design and delivery of the firm’s iOS compliance clients used by 20 000+ customers worldwide.
- Introduced SwiftUI and The Composable Architecture to modernise legacy Objective-C codebases, reducing feature lead-time by 30%.
- Mentored local and remote teams of engineers, championed automated testing and continuous deployment.
Black Swan Data (2018 – 2020) – Lead Mobile Engineer
- Led the ePOS-mobile payments programme spanning multiple airline clients; recognised internally as the subject-matter expert for currency conversion and payment integration.
- Authored comprehensive technical documentation that accelerated onboarding of new developers and cut ramp-up costs.
Seagull Systems (2008 – 2017) – Founder & Principal Engineer
Demian founded Seagull Systems in London, leading the agency to deliver over 50 iOS and macOS apps in collaboration with major clients including Accenture, HarperCollins, OAG, UBM, Dolce & Gabbana, and Chanel.
- Delivered 25+ major projects, including 4 apps that reached #1 in their App Store categories and 3 featured by Apple.
- Oversaw full lifecycle development across design, engineering, and client delivery, growing profitability year-on-year for 6 years.
Full Career History
Open Source & Community
Demian is a long-time advocate for open-source software and active participant in developer communities. He is the creator of the Seagull PHP web development framework, downloaded over 40,000 times and used by a global network of developers, with over 1,000 registered contributors across 72 countries. Beyond development, he helped grow the open-source ecosystem by organising community conferences and co-founding PHP-London, one of the UK’s leading PHP user groups.
In his professional roles, Demian has consistently encouraged the use of open-source tools and libraries within teams. He actively promotes the practice of open-sourcing proprietary code where appropriate, fostering collaboration, driving efficiency, and shortening development cycles.
He has spoken at various industry events on topics including rapid web app development, automated testing, and agile practices.
Technical Toolbox
- Languages: Swift, SwiftUI, Objective-C, PHP, MySQL, JavaScript, Python
- Frameworks: SwiftUI, TCA, Core Data
- DevOps: Jenkins, Docker, Fastlane, TestFlight, GitHub Actions
- Platforms: macOS, iOS, watchOS, Linux
Personal Note
Outside of software engineering, Demian is an dabbling musician with a passion for live music and painting. He values healthy living and eating, staying active, and spending quality time with his wife and son.