Custom app development in Palm Beach CountyKnow your price before you hire.
Mobile apps, web apps, AI features and payments, built by Simon Dziak, the senior developer you actually talk to. Fixed prices, everything in writing.
Mobile apps start from $9,000. 5 quick questions, then your contact details.
Get my quote- 126 public Fiverr reviews
- 5.0
- projects shipped since 2020
- 21
- paid upfront and on delivery
- 50/50
- Eastern Time hours, Boynton Beach
- ET
Selected work since 2020
Apps, AI and platforms we’ve shipped
2023–now · Our own product
Workspace369
An all-in-one workspace for service businesses: CRM, proposals, invoicing and payments, scheduling and a shared email, SMS and voice inbox. Designed, built and run by App369.
2026 · Our own product
3693
2026 · Open source by Simon Dziak
SaaS MCP Connector
Client project
BILSTEIN (opens in a new tab)
2023 · Client project, built by Simon
Bull Horn GPS Alarm
2021 · Our own R&D
Deep Dream
What App369 builds
One senior developer across the whole product
The app, the web front end, the backend, the AI features and the payments.
iOS and Android apps, from a first release to fixing one that already has users.
- Flutter
- Swift
- App Store & Google Play
Fixed price: App Fix Ticket (from $450)
Mobile apps
iOS and Android apps, from a first release to fixing one that already has users.
Built by App36936932026 · Our own product- Flutter
- Swift
- App Store & Google Play
Fixed price: App Fix Ticket (from $450)
Founder and head developer
Who builds it
Work directly with the senior developer who builds your app
Here the person you talk to writes the code, from start to finish.
Simon Dziak, App369’s founder and head developer, leads every project himself. Larger firms hand projects to junior team members. At App369 there is no hand-off.
Meet Simon in 60 seconds: how App369 scopes, prices and builds your app.
Reviews
5.0Rated 5.0 across 126 Fiverr reviews
126 public Fiverr reviews since 2020, all copied word for word on our reviews page.
Working with Simon makes everything run so smoothly and better than I could ask for it. Amazingly communicative, extremely knowledgeable of coding and the backend processes. I strongly recommend.
“Working with Simon has been an absolute pleasure. He’s not only incredibly skilled with his code, but he also brought so much care and attention to detail, especially when creating a custom section template for my Shopify site. He made the entire process smooth and collaborative, and consistently went above and beyond to make sure everything looked and functioned beautifully, very much the way I've envisioned. Highly recommend him for anyone looking for thoughtful, top-notch development support!”
“Very detailed and professional. Understands full scope of project before advancing and has honest but critical feedback. such a pleasure with consultation and can't wait to get started.”
Fixed-price services
Fixed scope. Fixed price. In writing.
Paid upfront, and the work happens in writing; no call needed.
- App Fix Ticketfrom $450One reproducible bug in an existing mobile or web app, diagnosed and fixed.
- AI-Built App Rescuefrom $450A Lovable, Bolt or Cursor app checked end to end in 3 days, then its worst problems fixed at a fixed price.
- AI Feature or Agent Build$2,500One LLM feature or agent wired into your app or tools, with an eval set that shows how well it works.
- Web App MVP Sprintfrom $6,000A scoped web app MVP in Vue/Nuxt or React, with a fixed quote after a $450 written scoping.
- Stripe Billing Fix and Setup$950Subscriptions, webhooks, customer portal and failed payments set up or fixed, tested in Stripe test mode.
- API Integration$1,200Two systems connected through their APIs, with retries, logs, failure alerts and tests.
- Firebase Security Rules Audit + Fix PR$950Tests whether one user can read or edit another customer’s data, and fixes what it finds.
- MCP Connector for your SaaS$2,500An MCP server over your existing REST API, so your product works inside Claude and ChatGPT.
- Firebase Cost-Cut Audit$750Where your Firebase or Google Cloud bill goes, with savings ranked by dollars a month and risk.
- Shopify Speed & Checkout Tune-Up$750Mobile speed and cart-to-checkout fixes on a duplicate theme, measured before and after.
- SaaS Launch Video$1,500A 60-second motion-graphics product video built from your real screens, plus a 15-second and a vertical cut.
- Shorts-as-a-Service$1,500/monthTwelve vertical motion-graphics Shorts a month from your docs, posts or a voice memo. No filming.
- Workspace369 setup, done for youfrom $450Proposals, signatures, invoices and payments set up in one place for freelancers and small agencies.
- AI Agent Engineering Setupfrom $750Your repos made ready for Claude Code, Codex and Cursor agents: a written diagnostic first, then a setup sprint.
- Monthly Dev Subscriptionfrom $1,495/monthOne development request at a time, most back in about 2 business days. Pause or cancel anytime.
How it works
From idea to launch: most MVPs take 6–12 weeks
Understanding your idea
We start by listening to your idea and understanding your goals, then we create a plan to bring your idea to life.
Design & development
We design and build your app or website with you in mind, making sure it's easy to use, visually appealing, and works on all devices.
Launch & support
Once your app or website is ready, we launch it and continue to provide support, making sure it works flawlessly as your idea grows.
Technologies we use
Pick the tool that fits the job
Not the other way round.
// The tools we pick from, matched to the job
export const stack = [
- 'Flutter',
- 'Swift',
- 'Kotlin',
- 'Firebase',
- 'Google Cloud',
- 'TypeScript',
- 'Vue',
- 'Node.js',
- 'Nuxt',
- 'React',
- 'Python',
- 'PostgreSQL',
];
Custom iOS and Android apps built to be easy to use, reliable, and scalable. Whether it's a personal project, startup, or enterprise tool, App369 turns your idea into a production-ready application.
Follow along Behind the builds
@app369company → (opens in a new tab)
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Simon DziakFounder and head developer
Start here
Get a personalized assessment by email
Submit your project details and we’ll reply by email with a personalized assessment, usually within one business day.
Prefer a call? Consultations are $100 per 15 minutes, paid upfront.