David Xiao
Full Stack Developer, Secco Squared
Internal tools, AI agents and production web apps in TypeScript, React, PostgreSQL and Python.
Cut 20 minutes of manual entry per offer and surfaced 28,560 missed offers by building OfferBridge, a Next.js/TypeScript tool that pulls offers from partner REST APIs and logs imports in PostgreSQL.
Approach & current work
I'm a Full Stack Developer at Secco Squared, working across TypeScript, React, PostgreSQL, and Python. I like hard, load-bearing work: tools that replace manual entry, APIs that don't lose data when a partner goes down, and pipelines that make systems cheaper to change.
At Secco Squared I built OfferBridge, a Next.js/TypeScript tool that pulls offers from partner REST APIs, an AI agent in Slack on OpenAI tool calling, and a scheduled job that pauses capped offers before they overspend partner budgets; I also rebuilt a video sales funnel, saving $1,300+ per month. On the side I build Agentflow (a Python CLI that gates AI-written code changes behind schemas and human sign-off), Kyarafit (offline-first web and mobile apps that sync SQLite to Convex), and ForgeArena (a React fitness app gated on CI).
- TypeScript
- JavaScript
- Python
- SQL
- HTML/CSS
- PHP
- Bash
- React
- Next.js
- React Native
- Node.js
- Express
- Fastify
- Tailwind CSS
- REST APIs
- PostgreSQL
- MySQL
- Supabase
- Convex
- SQLite
- Firestore
- Git
- GitHub Actions CI/CD
- Docker
- Vercel
- Vitest
- Jest
- Playwright
- TDD
- Agile Scrum
- OpenAI API
- MCP
- Claude Code
- Codex
- Cursor
Work
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Personal Portfolio
xiaoOS: a Go + TypeScript portfolio with a procedural city, windowed applications and independently readable project and resume documents.
How it’s built
Built from scratch with Go and Gorilla Mux serving semantic HTML templates, then enhanced with vanilla TypeScript. One lazy-loaded three.js city carries the camera from the boot sequence into the desktop; applications open as windows on desktop and documents on mobile. GSAP coordinates the cinematic, with a static acquisition sequence for reduced motion and an SVG fallback when WebGL is unavailable. The project index supports filtering, technology relationships and live captures of locally hosted games. A LaTeX source supplies the downloadable resume; esbuild, Tailwind CSS and Docker support the Heroku build.
- Go
- TypeScript
- HTML/CSS
- Tailwind CSS
- LaTeX
- Docker
- Heroku
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Kyarafit
Cross-platform cosplay wardrobe app — TypeScript monorepo (Next.js web, Expo RN mobile) on a Convex reactive backend with Stripe-gated tiers.
How it’s built
A cross-platform cosplay wardrobe and outfit planning app. Organize costume pieces in a digital closet, link them into character builds, plan conventions day by day, and auto-generate smart packing lists. Built as a TypeScript monorepo with a Next.js web app, React Native (Expo) mobile client, shared design system, and Convex serverless backend with real-time reactive queries. Features offline-first mobile storage via SQLite, Better Auth authentication with Google OAuth, tiered subscriptions via Stripe.
- TypeScript
- React Native
- Next.js
- Expo
- Convex
- FastAPI
- Python
- TailwindCSS
- Docker
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OutfAI
Wardrobe-first AI stylist redesigned around an editorial landing page, closet-aware recommendations, and clear outfit reasoning.
How it’s built
A Next.js + Convex wardrobe app that turns closet uploads, mood, weather, calendar, and preferences into explainable outfits. The May 2026 redesign moved OutfAI from a dashboard-first feel to a full-bleed editorial landing page with a styled brief, generated look, and why-it-works panel that makes the product value legible before sign-up.
- Next.js 15
- React
- TypeScript
- Tailwind CSS
- Convex
- Better Auth
- Framer Motion
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SavvyBurrow
BG Media's umbrella lead-generation site: six verticals on savvyburrow.com subdomains, shared legal pages, and pointer-reactive WebGL2 dither shaders on Next.js 16.
How it’s built
BG Media's umbrella lead-generation site, built at Secco Squared. The root site presents six lead categories; each vertical lead site lives on a savvyburrow.com subdomain (such as tax.savvyburrow.com) and shares one set of privacy, terms and California privacy pages on the root, with return-to-origin links that keep tracking parameters intact. Built in Next.js 16 with GSAP, Lenis smooth scrolling, three.js and custom pointer-reactive WebGL2 ordered-dither image shaders, deployed on Vercel. Performance work removed lag while keeping the animations intact. Source is private company code.
- Next.js 16
- React
- TypeScript
- GSAP
- Lenis
- three.js
- WebGL2
- Vercel
Experience
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Full Stack Developer at Secco Squared
- Cut 20 minutes of manual entry per offer and surfaced 28,560 missed offers by building OfferBridge, a Next.js/TypeScript tool that pulls offers from partner REST APIs and logs imports in PostgreSQL
- Let staff get live offer and sync answers in Slack by building an AI agent on OpenAI tool calling that runs multi-step lookups, checks each user's permissions, and asks before making changes
- Stopped live offers from overspending partner budgets, a revenue leak raised by the business team, with a scheduled Vercel cron job that pauses capped offers via the Everflow API and alerts Slack
- Kept sales leads from being lost when partner systems went down by building a Next.js REST API on Supabase (PostgreSQL) that saves each lead first, then delivers it with automatic retries
- Saved $1,300+ per month by rebuilding a video sales funnel as responsive HTML/CSS pages in Next.js and React, with video streaming and ad-conversion tracking
- Shipped 175+ merged pull requests across 11 company codebases by setting up GitHub Actions CI/CD pipelines, writing tests first (TDD), and using AI agents (Claude Code, Cursor) to write and review code
- TypeScript
- React
- PostgreSQL
- Python
-
Software Engineer Intern at Unadat
- Shipped service extractions across several production releases by decomposing a PHP/JavaScript monolith alongside senior engineers and testing changes before code review
- Sped up slow REST endpoints by batching repeated MySQL queries and validating inputs in the PHP backend
- Made UI fixes land once instead of in every copy by consolidating duplicate forms and modals into shared React components, delivered in Agile Scrum sprints
- JavaScript
- PHP
- React
- MySQL
- RESTful APIs
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Bachelor of Arts, Computer Science · CUNY Hunter College
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