I'm 12. I don't have a laptop. I built a full-stack AI SaaS on my Android phone.

Hi everyone! 👋

My name is Harun. I am 12 years old.

I don't own a laptop or a PC. My entire development environment is a POCO C55 Android phone and a free code editor called Acode.

Today, on my school holiday, I decided to stop watching tutorials and actually ship something. I built KODA, a full-stack AI coding mentor.

🛠️ The Stack (100% Free Tier)

• Frontend: Vanilla HTML, CSS, and JavaScript (Hand-coded on a 6.7" screen).
• Backend & Auth: Supabase (PostgreSQL + Row Level Security).
• AI Brain: Groq (using the llama-3.1-70b-versatile model for speed).
• Hosting: Netlify (Drag-and-drop deploy).
• Mobile Wrapper: Median (to turn it into a native Android app with a splash screen).

🐛 The "Boss Fight" Bugs

Building on mobile is hard. The screen is small, and debugging is painful.

1. The Mobile Viewport Trap:
I used height: 100vh for my app container. On desktop, it's fine. On mobile Chrome, the address bar hides part of the screen, pushing my input box off the bottom!
The Fix: I had to switch to height: 100% on the html, body and use env(safe-area-inset-bottom) to glue the input area above the navigation bar.

2. The Supabase RLS Silent Killer:
My profiles table was updating, but my chats table was empty. No errors in the console.
The Fix: I realized RLS (Row Level Security) was blocking inserts because I hadn't granted permissions to the authenticated role. I wrote a SQL script to GRANT ALL ON public.chats TO authenticated and suddenly, the data started flowing.

🏆 User #1

My older brother (an engineering student) was my first beta tester.
He opened the app and typed: "Vanakam da mapila" (Hello friend/brother-in-law in Tamil).
When I teased him for treating the AI like a person, he replied: "THAT'S MY FRIEND TEXTING YOU, IDIOT." 😂

That was the moment I knew the product felt "alive."

🚀 Try KODA

I deployed it live on Netlify. It has multi-chat history, code syntax highlighting, and a "Panic" button that explains things "Like I'm 5."

Live Link: koda-aicodementor.netlify.app

🙏 I Need Your Feedback

Since I am learning solo, I would love for senior developers to roast my code or tell me what to build next.

• Should I add Streaming (typewriter effect)?
• Should I add a PWA manifest?

Thanks for reading my story!