Sonny Castro
Creating with code. Small details matter.
Overview
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About Me
I enjoy taking products from zero to one. Over the past few years, I've built full-stack web and onchain applications using Next.js, React, and Solidity. I led development on Ikebana Miami, Milady Colombia, and Hypachinko, and worked on AI Arena's onchain infrastructure at ArenaX Labs. This past year, I also shipped full-stack features at SAI. I'm currently building out new ideas and open to new opportunities.
Stack
Blog
Experience
ArenaX Labs
- Developed within a pnpm + Turborepo monorepo with Dockerized services.
- Built APIs, endpoints, and UI flows for model submissions, leaderboard tracking, and benchmarking.
- Optimized performance and usability to improve platform responsiveness for large-scale ML competitions.
- Worked on SAI platform for large-scale ML competitions.
- TypeScript
- React
- Next.js
- Node.js
- Docker
- Turborepo
- MongoDB
- Tailwind CSS
- API Development
SteakWallet (acquired by Omni)
Milady Colombia
Education
Projects(4)
A native iOS app for tracking the little promises friends make to each other — "I owe you a coffee," "Date night on me," "I'll wash the dishes."
Built around a coupon-card metaphor: every IOU is a tear-stub ticket you can send, redeem, fulfill, or break. Two taps to send, one tap to redeem.
- Backend: Supabase Postgres with row-level security, pg_cron for auto-expiry and reminder pushes, edge functions for the APNs pipeline
- Real-time sync between sender and recipient with optimistic UI
- Auth: Apple Sign In + Phone OTP (Twilio), with email/phone-based promise linking for unregistered recipients
- Monetization: RevenueCat-powered free trial → Pro subscription
- Trust & safety: block flow with RLS-enforced send blocking across all identifier types
- Design system: custom typography, palette, haptics, sound effects, and a 6-frame onboarding flow
Live on the App Store since May 2026.
- SwiftUI
- iOS
- Supabase (Postgres + RLS + pg_cron)
- RevenueCat
- APNs
- Fastlane
- Apple Sign In
- Twilio Phone OTP
Modern floral design studio website for Ikebana Miami.
- Built a full-featured studio website with services, events, subscriptions, and contact pages
- Japanese-inspired design aesthetic reflecting the art of ikebana
- Custom event booking and subscription flows
- Live at Ikebana Miami
- React
- Next.js
- TypeScript
- Tailwind CSS
- Vercel
- Stripe
On-chain arcade experience on HyperEVM using vaults to reward users.
- Designing non-custodial vaults for transparent reward accrual and distribution
- Building lightweight mint/play flows and leaderboards
- Focused on low-friction UX and verifiable onchain rewards
- Live at Hypachinko
- Solidity
- HyperEVM
- Vaults
- React
- Next.js
- Node.js
- Viem
