COSAI
Ithiel Studio by COSAI

Your Technology Partner for iOS.

I don't just build your app. I stay on as your technology partner. Competitor research, working prototype, and a clear plan, all before you spend a dollar. Then a production app built to scale, with ongoing development and strategic guidance for as long as you need.

Limited availability. Currently accepting 2 clients per quarter.

Native Swift / SwiftUIFree Prototype Before You PayYou Own Every Line of CodeProduction-Ready in Weeks100% Completion RateDelivery or You Don't PayNative Swift / SwiftUIFree Prototype Before You PayYou Own Every Line of CodeProduction-Ready in Weeks100% Completion RateDelivery or You Don't Pay

What We've Built

Shipped. Tested. Running in Production.

ProductivityApp Store

FlowState

Pomodoro timer with focus tracking and analytics. Built in 7 days.

SwiftUISwiftData
Location + SocialProduction

PulseCheck

Real-time location-based Q&A with MapKit and Supabase. 68 Swift files.

SwiftUIMapKitSupabaseCoreLocation
AI + CommunityProduction

Discipler

AI-powered discipleship app with personalized guidance. OpenAI integration.

SwiftUIOpenAI APISupabase

Currently building ShowMe: a real estate marketplace with Stripe Connect.

Meet Gerrit

I build production-ready iOS apps for founders who need to get to market, not wait 6 months and spend $50K at a dev shop.

Every app is native SwiftUI, built by me personally. You work directly with the person writing your code. No handoffs, no account managers, no surprises.

After launch, I don't disappear. Most of my clients continue with me as their technology partner: new features, strategic guidance, and ongoing development for as long as they need.

When a project needs deeper design or backend support, I bring in trusted specialists. One point of contact. Fixed scope. Quality first.

How It Works

4 Calls. Zero Risk. One Partner.

1

Discovery Call

30 min

I learn your business, your vision, and the problem you're solving. No sales pitch. Just understanding.

Within 48 hours, you get three things, free: Competitor analysis. Working prototype. Full proposal with pricing.

2

Strategy Call

30 min

I walk you through your competitors, demo the working app, and present the full plan. If you love it, we lock in and collect the deposit.

3

Scope Review Call

30 min

We refine features with your feedback, lock the final scope, and confirm the build timeline. This is where the plan gets bulletproof.

I build your app. You get daily progress updates with screenshots. No disappearing acts.

4

Delivery Call

30 min

Your finished app, on your phone, working. We walk through it together. One round of feedback, then App Store submission. Most clients continue as technology partners from here.

Investment

One Price. Everything Included.

A traditional agency quotes this at $40,000 to $150,000 and takes 3 to 6 months. A full-time CTO costs $250,000 to $400,000 per year plus equity. I deliver the same outcome in weeks, not months, and I stay on as your technology partner for as long as you need.

Technology Partnership Build

$18,000 - $25,000

Your idea, built to production. Scope-dependent pricing.

Everything included:

Custom App Build($40K value)

Production-ready native Swift iOS app. Not a template, not no-code. Real code built to scale.

Backend and Infrastructure($10K value)

Supabase: auth, database, real-time subscriptions, row-level security, Edge Functions configured and running.

Competitor Analysis and Market Research($5K value)

8+ competitors mapped with pricing, features, and positioning matrix. Market gaps identified. Positioning validated before a single line of code is written.

App Store Launch and Deployment($5K value)

Full submission: ASO-optimized metadata, screenshots, review process managed start to finish. Custom landing page included.

30-Day Post-Launch Support($5K value)

Anything within scope that breaks gets fixed. No charge. No questions.

Technology Roadmap($3K value)

6-month plan: what to build next, in what order, based on your business goals and user data.

90-Day Priority Direct Access($7.5K value)

My personal number. Priority communication. Daily progress updates with screenshots. Same person from start to finish.

Full Source Code and Handoff

100% of the codebase is yours. GitHub repo transferred. Full documentation. You own everything.

Revenue Infrastructure

Subscriptions, payments, or marketplace splits wired up and tested. If your app charges money, it works on day one.

Analytics and Crash Reporting

Firebase Analytics, PostHog behavioral analytics, Crashlytics. You see what users do from launch day.

Architecture Documentation and Walkthrough

Full documentation of architecture decisions plus a recorded Loom walkthrough so you (or a future developer) understand every choice.

Total value: $75,000+

Your investment: $18,000 - $25,000

50% at contract signing. 50% on delivery. Wire transfer, Zelle, or Stripe invoice.

Technology Partnership

$5,000/month

I don't just build your app. I stay.

Feature sprints: one sprint per month
Crash monitoring and same-day bug fixes
App Store updates and management
Architecture decisions and technical strategy
Priority response time (Slack + phone)
Quarterly roadmap review
The same person who built your app, not a ticket in someone's queue

For existing apps, larger builds, or multi-app partnerships: let's talk.

Book a Discovery Call

5% of every project goes to fighting child trafficking.

The Guarantee

Before you spend a dollar, I build you a free working prototype. You've already seen your app working before we talk money.

If I don't deliver on time, you don't pay the second half. If you want to walk away during the build, you can. No second payment. 30 days of bug fixes after launch. Anything breaks, I fix it.

Your only risk is a 5-minute form and one phone call.

Get Started

Currently accepting 2 clients per quarter.

Beyond the Build

Most developers disappear after delivery. I stay.

After your app launches, I continue as your technology partner:

  • Crash monitoring and bug fixes, same day
  • New features as your business grows, one sprint per month
  • iOS updates and App Store management
  • Strategy calls, same person, same phone number

You focus on your business. I handle the technology.

“I don't know how to fix bugs. Do you actually do this yourself?”

A founder, on a strategy call. That's exactly why the Technology Partnership exists.

Founding Clients

Be One of the First.

I'm currently accepting founding clients for the Technology Partnership. Founding clients get priority access, direct communication, and the most hands-on experience I'll ever offer.

Frequently Asked Questions

Ready to See Your App?

Fill out a 5-minute form. I'll research your competitors, build you a working prototype, and send a clear proposal, all within 48 hours, before you pay a dollar.

48-hour turnaround on your free prototype. No commitment.