Hi, I'm Karsten Hoekstra
I design and build AI-powered iOS apps and fast, modern websites — from first idea to the App Store.
01About
A bit about me
I'm a developer from Leeuwarden studying HBO-ICT at NHL Stenden. Most of my time goes into building iOS apps with SwiftUI and websites with Next.js — often with an AI twist, like the image tools behind EMAAi and ImageIQ.
I like owning a product end to end: designing the interface, wiring up the backend, and shipping it to real users.
Outside of coding, I enjoy traveling, spending time with my girlfriend and family, and being around animals.
- Based in
- Leeuwarden, NL
- Studying
- HBO-ICT · NHL Stenden
- On the App Store
- EMAAi
- Focus
- iOS, web & AI
Currently learning
My Journey
- 2026
StableNote
Built StableNote, a horse-care app for iPhone with passport scanning and caregiver sharing, now in public beta.
SwiftUIConvexRevenueCat - 2025
ImageIQ App
Developed an AI-powered image editing and generation app for iOS with advanced editing features.
SwiftUIConvexGemini - 2024
EMAAi App Launch
Published my first iOS app on the App Store — an AI-powered art generation tool.
SwiftUIFirebaseAI - 2023 - Present
NHL Stenden HBO-ICT
Started programming and studying HBO-ICT at NHL Stenden University in Leeuwarden.
JavaC#Web Dev - 2020 - 2023
High School
Completed secondary education with a focus on science and technology.
ScienceTechnology
02Projects
Selected work
iOS apps and websites I designed, built, and shipped.
StableNote
Horse Care iOS App & Website
A horse-care product I built end to end: a native iPhone app for owners and caregivers, and the bilingual marketing website that brings in beta testers.
iOS app
Care records, care plans, recurring care, and reminders for every horse. Scan a horse passport to fill in its details automatically, share horses read-only with caregivers, and export PDF care reports.
Website
stablenote.app: an English and Dutch site with light and dark themes, a bot-protected TestFlight waitlist, localized welcome emails, and SEO with structured data and social cards.
EMAAi
AI Art Generation iOS App & Website
An AI art generator for iPhone, live on the App Store, plus the landing page that promotes it.
iOS app
Turn text prompts into AI artwork in a range of styles. Includes subscription tiers, a points system, and AI-powered prompt refinement, built with SwiftUI on a Firebase backend.
Website
emaai.app: a responsive Next.js landing page that presents the app's features, pricing plans, and how it works, and sends visitors to the App Store.
ImageIQ
AI Image Editing iOS App
A professional-grade AI-powered image editing and generation app for iOS. Features 16 edit types including background removal, style transfer, upscaling, and text-to-image generation powered by Google Gemini. Built with SwiftUI, SwiftData, Convex real-time backend, and RevenueCat subscriptions.
Black Horse Projects
A basic website for Black Horse Projects showcasing their services and company information. Features include user authentication, profile management, contact forms, and an about page.
YouTube Video Downloader
A Python command-line tool for downloading YouTube videos in different qualities. Features progress tracking and support for audio-only downloads.
03Skills
What I build with
The languages, frameworks, and services I use to ship products.
Mobile
- SwiftUI
- SwiftData
- RevenueCat
Web
- TypeScript
- React
- Next.js
- Tailwind CSS
- JavaScript
- HTML
- CSS
Backend & AI
- Firebase
- Firestore
- Cloud Functions
- Supabase
- Convex
- Google Gemini
- Python
- PHP
Tools & Design
- Git
- GitHub
- Figma
- VS Code
- WordPress
- Canva
04Contact
Let's build something
Have a project in mind or want to collaborate? I'd love to hear from you.
Location
Leeuwarden, Netherlands