My AI-driven side project

passed 500 GitHub stars

Lessons learned

Kota Hayashi

Japanese version

React Native & Flutter Meetup - 2026/04/24

About me

Kota Hayashi

X profile screenshot
React Native & Flutter Meetup - 2026/04/24

What I built

CC Pocket

  • An app for controlling Codex and Claude from a phone
  • Built for a native experience, not a terminal UI
  • A personal Flutter app
  • Released the iOS version on 2026/03/06
CC Pocket GitHub repository card
React Native & Flutter Meetup - 2026/04/24

App screens

CC Pocket iPad screenshot CC Pocket iPhone screenshot
React Native & Flutter Meetup - 2026/04/24

Early traction

Metric Number
GitHub Stars 626
App Store reviews (Japan) 21 / 4.8
Google Play reviews 10 / 5.0

  • A strong start about two months after launch

  • The UI/UX feedback has been especially positive

  • AI helped me achieve both speed and polish

App Store review screenshot
React Native & Flutter Meetup - 2026/04/24

CC Pocket architecture

Mobile / macOS app
Flutter / client
Communicates via WebSocket
Devices connect through Tailscale, etc.
Bridge server
Self-hosted on Mac / TypeScript
Manages Codex / Claude sessions
Registers device tokens
Sends notifications via FCM
Firebase / FCM
TypeScript / notifications
  • Run the Bridge on a Mac to control Codex / Claude
  • Connect from a phone to operate AI sessions remotely
  • Use Firebase only for notifications
React Native & Flutter Meetup - 2026/04/24

Why Flutter

  • I had built SwiftUI macOS apps, React Ink TUI tools, and more with AI-driven development
  • They looked good and got some early attention on social media
  • But the UX was not polished enough, so I stopped using them myself
  • To ship quality, you need both AI and real understanding of the chosen technology
  • I put familiar Flutter at the center of the product
  • For surrounding pieces like the Bridge, I used TypeScript
React Native & Flutter Meetup - 2026/04/24

AI tools I used

Tool Main role
Claude Code Early design, implementation, environment setup
Codex Current main tool, from design through coding
Antigravity Final UI polish and asset generation
  • I did not rely on a single tool; I used each one for its strengths
React Native & Flutter Meetup - 2026/04/24

Main development: Claude Code and Codex

  • I used AI for almost everything: design, implementation, and environment setup
  • Early on, I used Claude Code
  • Now I have mostly moved to Codex
  • Model quality is good enough for practical use in both cases

Plan history:

  1. Claude Max $100
  2. Claude Max $100 + Codex Plus $20
  3. Claude Pro $20 + Codex Pro $100
  4. Codex Pro $100
React Native & Flutter Meetup - 2026/04/24

Why Codex is my main tool now

  • The biggest reason is cost performance
  • In my workflow, at the same price range, Codex gave me more usage headroom

A major difference: tolerance for third-party tools

  • Codex: subscription tokens can be used from third-party tools
  • Claude: third-party usage became a terms-of-service violation

Third-party tools include OpenClaw, OpenCode, and CC Pocket itself

React Native & Flutter Meetup - 2026/04/24

Antigravity handled design

  • The multimodal strength of Gemini-family models feels important here
  • The generated code quality is low
  • But if you think of it as a designer who can write a little code, it is very capable
  • It was especially useful for app icons, generated assets, and final UI adjustments

Antigravity contributed a lot to the positive feedback on CC Pocket's UI/UX

  • By the way, being from Google does not make it magically better with Flutter...
React Native & Flutter Meetup - 2026/04/24

Supporting tech that worked well with AI

  • shorebird
    Easy remote device testing and convenient OTA-style updates
  • marionette mcp
    Important for letting AI verify the UI by itself
  • BLoC
    Easier for AI to handle than overly flexible state management
  • GitHub Actions
    Easy for AI to automate because errors are available through CLI and API

I will cover these in the following slides

React Native & Flutter Meetup - 2026/04/24

shorebird

  • https://shorebird.dev/
  • An OTA (Over The Air update) tool for Flutter
  • Lets you release without app store review
    • Avoids losing AI's productivity gains to review delays
  • Also useful when you cannot connect directly to a Mac for device testing
    • Much faster than distributing through TestFlight

OTA support may matter a lot in AI-first development

  • Honestly, Expo probably has a better experience in this area
React Native & Flutter Meetup - 2026/04/24

marionette mcp

React Native & Flutter Meetup - 2026/04/24

BLoC

  • Riverpod and BLoC are both popular state management options in Flutter
  • With Riverpod, I felt AI-generated code was less stable because the style is very flexible
  • After switching to BLoC, state management has been reliable even when I mostly delegate it to AI

My impression is that stricter rules reduce generation stress and fit AI better, though I have not used BLoC deeply enough to make a stronger claim

React Native & Flutter Meetup - 2026/04/24

GitHub Actions

  • Because the project is public, using it for free is a big advantage
  • Beyond that:
    • Error details are available through CLI and API, so AI can work with them easily
    • When choosing CI/CD tools, avoid services where important information is only visible in the GUI
React Native & Flutter Meetup - 2026/04/24

Summary

  • Even in AI-driven development, understanding the chosen technology matters
    • A good balance is to center the product on technology you know well while adopting new tools around it
  • Claude Code / Codex for main development, Antigravity for design worked well
    • If I had to recommend only one for individual developers, I would recommend Codex
  • I also introduced supporting technologies
    • OTA updates and feedback loops are especially important
React Native & Flutter Meetup - 2026/04/24