Kieran Crown
Lead Mobile & Full Stack Engineer
I build polished, high-quality mobile apps with React Native, Expo, and SwiftUI, backed by deep GraphQL and cloud expertise. I thrive in small, fast-moving teams where I can own the full stack from design to production.
About
With over 10 years of experience as a software developer, I specialise in building high-quality mobile applications using React Native and Expo. I have delivered products across fintech, payments, and consumer tech, with particular depth in GraphQL-driven architectures and end-to-end ownership of mobile releases. I'm passionate about crafting polished user experiences and thrive in small, fast-moving teams where I can take ownership from feature design through to production.
At a glance
- Location
- London
- Experience
- 10+ years
- Focus
- Mobile apps, polished UX, small fast-moving teams
- Certification
- AWS Certified Developer
Projects
Personal projects where I explore ideas and push my craft
- Agent-wallet signing: one EIP-712 approval, then orders are signed locally with the Hyperliquid SDK
- Custom Skia candlestick chart with a UI-thread crosshair and a sprite atlas pet that costs one draw call
- Keyboard-driven walkthrough that learns from dismissed findings, then posts inline comments and a summary review to GitHub
- Stack review that checks every layer against its parent, then catches issues that only appear across the stack
- Linear-style desktop app shell built with Next.js 16, React 19, and live updates via Supabase Realtime
- Native SwiftUI iOS app with Liquid Glass alongside an Expo mobile app using React Native Skia and Reanimated
Experience
Onsera Health
Lead Mobile EngineerBuilt Onsera Health's mobile app from zero to 400+ real users in three months, pairing AI-assisted development with over a decade of engineering experience.
- Shipped the React Native and Expo app from a blank repo to a live product in three months
- Used AI coding agents as a force multiplier, directing and reviewing their output to production quality
- Own the architecture, releases, and technical direction of the mobile platform
Slice Mobile
Full Stack EngineerSenior full stack engineer in a team of fewer than four, owning both the Expo-based mobile app and the GraphQL orchestration layer integrating with legacy telecom APIs.
- Own the full Expo mobile app and GraphQL orchestration layer for a telecom product
- Span feature development, bug fixes, app releases, CI/CD maintenance, and test coverage
- Serve as primary owner of the mobile codebase, collaborating closely with backend engineers
- Balance frontend polish with backend integration in a fast-paced, small team environment
nsave
Design EngineerSole mobile engineer at a digital banking app focused on savings and financial inclusion, driving a significant modernisation effort across the React Native codebase.
- Owned the full React Native codebase as the sole mobile engineer
- Migrated the app to the latest Expo SDK and React Native's new architecture
- Implemented a design system using Shopify Restyle and Reanimated
- Built CI/CD pipeline in GitHub Actions with integrated Maestro end-to-end tests
- Reworked state management for improved reliability across financial features
- Contributed to the app's crypto features alongside the core savings product
Bumble Inc
Mobile EngineerWorked on Official, a relationship wellness app acquired by Bumble, leading a codebase rewrite and expanding test coverage.
- Led a full rewrite of a codebase originally built by contractors, improving quality and maintainability
- Expanded Maestro end-to-end test coverage, improving release confidence and reducing production issues
- Contributed to sprint planning and worked closely with product to shape the roadmap
- Consistently brought ideas to improve UX and overall app quality
Utility Warehouse
Software EngineerBuilt mobile features for the cashback and payments team, including leading Apple Pay and Google Pay integration.
- Led the implementation of Apple Pay and Google Pay, coordinating directly with both companies through certification
- Built contactless payment acquisition, swipe-based transaction history, and cashback card management features
- Owned the redesign of the retailer's view and improved transaction list performance
- Collaborated with design and two engineering teams to build a shared UI component library adopted across multiple apps
Nagra Media
Software EngineerContributed to the React Native integration layer connecting with existing iOS, Android, and web platforms at a digital media protection company.
- Contributed to the React Native integration layer connecting with existing native platforms
- Gained experience in cross-platform development and integrating modern mobile frameworks with established native systems
Vpress
Full Stack DeveloperConsolidated backend infrastructure and led frontend modernisation at a leading UK WebPrint provider.
- Migrated from multiple Node.js servers to a unified AWS deployment using Terraform
- Led frontend modernisation from a legacy Java stack to Next.js
- Improved performance, maintainability, and developer experience across the platform
Raytheon
Mobile Cloud EngineerWorked on mobile cloud engineering initiatives at a major defence and aerospace company, gaining exposure to enterprise-scale cloud infrastructure.
- Worked on mobile cloud engineering initiatives within a highly regulated environment
- Gained exposure to enterprise-scale cloud infrastructure and security-focused development practices
- Obtained AWS Certified Developer certification
Gravit8
Software EngineerBuilt interactive digital experiences for brands and event organisers at a creative technology agency.
- Built a company-wide mobile app using React, Cordova, and Node.js
- Developed an iPad wall installation for clients including TikTok, a system where hundreds of iPads sync to display a single video
- Each device supported independent interaction and seamless spatial repositioning using QR-based recognition
Skills
Mobile
Web3
Frontend
Backend & Data
Cloud & DevOps
Tools
Contact
- Phone
- 07405962950
- Location
- London