The DeveloperMeet the Developer Behind App369
App369 is founder-led: every project is built by a senior developer who has shipped and maintains production apps in mobile, web, and AI.
Simon Dziak
Founder & Lead Developer
Simon founded App369 with a mission to build technology that drives real business results. He builds every client project himself and also built and runs Workspace369, a production Flutter and Firebase platform with a native iOS app.
His technical expertise spans Flutter, Swift, Kotlin, Vue.js, Node.js, Firebase, and Google Cloud Platform. He specializes in translating complex business requirements into clean, scalable architecture.
He works in writing, at fixed prices, and you keep the code. Small jobs have one published price; bigger builds start with a $450 written scope that turns into one fixed quote.
Core Expertise
- Flutter
- Swift
- Kotlin
- Vue.js
- Node.js
- Firebase
- Google Cloud
- TypeScript
- React
- UI/UX Design
- System Architecture
- AI Integration
Writing
Recent articles by Simon
Insights on app development, technology trends, and building successful software products.
App Development
Turn a Prototype Into a Real App: Phases and Costs in 2026
A clickable prototype shows the screens, not accounts, saved data or payments. The phases from prototype to a live web and iOS app, and what each costs.
Read moreDevelopment Costs
Android App Development Cost (2026)
Android app development cost in 2026, worked from the BLS median developer wage, plus Google Play costs only Android has: a 25 USD fee, testing, API updates.
Read moreDevelopment Costs
Custom CRM Development Cost (2026): Agency Prices Compared
Custom CRM development cost in 2026: agencies publish $15,000 to $100,000 for a first version. App369 builds one from $6,000 after a $450 written scoping.
Read moreAI & Technology
How Much Does Firebase Cost in 2026? Prices and 3 Examples
What Firebase costs in 2026: Spark and Blaze free limits, Firestore, Cloud Functions, Hosting and Auth prices from Google, and worked bills for 3 app sizes.
Read moreAI & Technology
How to Build an MCP Server in 2026: Step by Step with Code
Build an MCP server over your existing REST API with the TypeScript SDK v2: tools, Streamable HTTP, Inspector tests and OAuth, on the 2026-07-28 spec.
Read moreAI & Technology
AI API Errors: 7 OpenAI, Claude, Gemini and MCP Fixes (2026)
AI feature broken by a 401, 429 or 529, or an MCP connector that won't connect? 7 OpenAI, Anthropic, Gemini and MCP errors, what each means and how to fix it.
Read moreStart here
Work with Simon
Simon builds every App369 project himself. Send your project details, or book a consultation ($100 per 15 minutes, paid upfront) to talk it through with him.