# KODA is a coding mentor built on a $150 POCO C55 Android phone > Source: > Published: 2026-09-17 16:27:08+00:00 # KODA is a coding mentor built on a $150 POCO C55 Android phone Building an AI developer tool doesn't require a high-end MacBook or a computer science degree. I'm 12 years old and I've launched KODA, an AI coding mentor designed to help beginners debug and build projects, using nothing but a budget Android device. To make this work on low-end hardware, I had to rely on a lean architecture that offloads the heavy lifting to the cloud. ## How the API fallback chain handles stability Since running local LLMs on a mobile device is out of the question, KODA uses a fallback system to ensure the app doesn't crash when an API hits a limit. The logic follows a specific sequence: the prompt is first sent to a high-speed, low-cost provider like Groq or OpenRouter. If the system detects a timeout or an API failure, it catches the error and automatically routes the request to a secondary provider. To keep track of this, I've set up telemetry that logs the `model_served` value in the database for every request, which allows me to identify and fix silent failures. ## Managing data with Supabase I used Supabase as the backbone because I didn't have the budget or the need for a custom backend server. It handles several critical functions for the app: - **Authentication:** This manages global users across different regions, including Japan, India, and China. - **PostgreSQL and RLS:** I use Row Level Security to protect the data. This ensures that while public submissions are readable, only authenticated admins have the permissions to view private logs or update champion statuses. - **Mobile Administration:** The Supabase web dashboard is fully functional in a mobile browser, which is how I manage the entire database from my phone. ## Keeping the frontend lean To avoid heavy React bundles and wasting free hosting minutes on complex build pipelines, I stuck to a mobile-first vanilla stack. The frontend is built entirely with vanilla HTML, CSS, and JavaScript. This keeps the site fast and prevents build-minute exhaustion. I also focused the UX on the constraints of a 5.5-inch screen, implementing dark mode and large touch targets for better usability on a phone. The goal of KODA was to stop beginners from spending three hours stuck on a single syntax error. By building this on a $150 phone, I wanted to prove that hardware constraints can actually drive creativity. You don't need the most expensive gear to ship a product; you just need to start building. If you want to test the tool or check out the implementation, you can find it here: ``` https://koda-aicodementortemp.netlify.app/ ``` And the community is over at the Discord: ``` https://discord.gg/NJCY7TB4y ``` [Next How cuTile Rust brings ownership safety to CUDA tile operations →](https://promptcube3.com/en/threads/9480/) ## All Replies （3） I'm curious if this works offline. I tried using Termux for a similar project but kept hitting error 127... I want to try this tonight. I've been fighting with AIDE for weeks, but I keep getting 403 errors... I'm dying to know if this actually scales. Did you use Python 3.11 for the backend or some other wrapper?