Caitlyn Carmabella Nayeli
Product Engineer
I build production platforms end-to-end—from database architecture to native mobile apps to payment integrations.
Recent: Built a 146,000-line wellness marketplace in 8 weeks as a solo engineer. Live in production with 96 screens, 5 payment providers, 7 languages, corporate B2B portal, and AI-powered support.
Based in Espoo, Finland • Open to product engineer roles
WHAT I BUILD
Production-grade platforms that process real transactions and serve real users.
I specialize in:
Two-sided marketplaces with automated matching, payments, and booking systems
Native mobile apps (iOS + Android) alongside responsive web platforms
Multi-tenant SaaS with role-based access and enterprise features
Payment integrations handling multiple providers, webhooks, and reconciliation
Real-time systems with WebSocket subscriptions and live updates
TECHNICAL CAPABILITIES
Core Stack (Active, Production Use)
Frontend & Mobile
React, React Native (Expo), TypeScript
HTML/CSS/JavaScript, Tailwind CSS
Responsive design, cross-platform development
Backend & Database
Node.js, Deno edge functions
PostgreSQL, SQL
Supabase (Auth, Database, Real-time, Edge Functions)
Infrastructure & Deployment
Vercel, UpCloud + Caddy
EAS (Expo Application Services)
Unix/Linux systems
Specialized Capabilities
Payment Systems
Multi-provider integrations (Visma Pay, Edenred, Stripe, Holvi, Smartum, ePassi)
Webhook handling and reconciliation
Invoice generation, refund processing
Real-time & Communication
WebSocket subscriptions, live data sync
Voice/video calling (Agora SDK)
Email automation (Mailgun)
AI Integration
Claude API, OpenAI API
Natural language interfaces
Automated content generation
Performance & Scale
Performance optimization (INP, bundle sizes)
Internationalization (7+ languages)
Database optimization, query tuning
Row Level Security policies
Design & Product
UX Design
User research and testing
Wireframing and prototyping
UI design and accessibility
Usability testing
Design Tools
Figma, FigJam
Canva, Adobe Suite
Miro (collaborative design)
Additional Technical
Languages & Frameworks
Python, Java, C++ (Object-Oriented Programming)
Vue.js, Next.js
React 19, React Native
Development Tools
Git/GitHub version control
Android Studio (native development)
PyCharm, IntelliJ (IDE environments)
Platform & Services
Google Analytics
API integration and design
Jira, Slack (team collaboration)
BACKGROUND
Currently: Studying at Metropolia University (Espoo) while building production platforms
Education: UX Design certification from Prime Digital Academy
Experience: 6+ years building web and mobile applications, 8+ years of design and product work
Location: Espoo, Finland (authorized to work in EU)
Contact: caitlyn.c.nayeli@gmail.com