Hoang Yell

Da Nang, Vietnam · Occasional onsite, Arizona, USA

• Architect of the ATS integration framework connecting Paradox to enterprise ATS partners — traffic grew ~360% YoY on the same SLA with zero critical production bugs; the reusable foundation I designed is now the standard starting point for new partner onboarding.
• Led the company-wide migration to an AWS data lake for logging and analytics (Kinesis, S3, Glue) — adopted as the standard approach across the organization.
• End-to-end owner of a core webhook and audit system — architecture through on-call — improving reliability and traceability for customer integrations.
• Built a Postman-like internal tool for large-scale API workflows — let non-engineers handle integration work for Compass Group, 7-Eleven, McDonald's, ADP, and other Fortune-500 clients.
• Built proactive observability (Datadog, Sentry, Slack alerts) that caught and defused a major queue incident before it escalated.
• Quality & mentorship: led the migration to Pytest for company-wide test coverage; mentor engineers on AI-assisted development (Cursor, Claude, Copilot) and set code-review standards across international and US teams.

Remote

• Delivered Python, regex, automation, and Screaming Frog SEO projects for clients worldwide.
• Maintained 100% 5-star satisfaction across every engagement.

Da Nang, Vietnam

• Shipped full-stack modules with ASP.Net, Angular, ReactJS, Node.js, and Swift / Xamarin.iOS for enterprise clients.
• Operated inside structured corporate teams and Agile delivery cycles.

Hue, Vietnam

• Designed REST APIs and optimised the schema for a scalable online card-game platform.
• Built WebSocket-based real-time gameplay in Python/Node.js — boosted player engagement +80%.
• Launched an in-game event that generated ~130M VND (~$5.5K) in revenue within two weeks.

yellorn.com — Data doctor, format studio & mock webhook API

Browser-based data workbench. 31 documented auto-fix passes recover broken JSON / XML / YAML / CSV from LLM output, log dumps, and Excel pastes; a 22-format viewer opens binary payloads (Parquet, Arrow, Excel, MessagePack, CBOR, Protobuf, BSON), AI model artifacts (Safetensors, GGUF, ComfyUI), and X.509 certificates — all decoded locally in a Web Worker, nothing uploaded. Converts across formats (JSON ↔ XML ↔ YAML ↔ CSV ↔ Python) and publishes any payload as a live mock REST endpoint with dynamic {{ }} tokens in under a minute. Built solo on React 19 · VINExt (Vite + RSC) · Cloudflare Workers · D1.

markdy.com — Open-source animation DSL engine

Write MarkdyScript, get animated scenes in the browser — a framework-agnostic animation DSL, not a diagram tool. Zero-dependency TypeScript parser (@markdy/core, ~12 KB), a Web Animations API renderer (@markdy/renderer-dom, ~22 KB), plus Astro and MDX bindings (@markdy/astro / @markdy/mdx). Chapters, camera pan / zoom / shake, stick-figure actors with articulatable limbs, and a forgiving-by-default / strict-on-demand parser. Designed to be AI-agent-friendly — ships an AGENT.md so LLMs can generate, validate, and iterate scenes directly.

hoangyell.com — Personal blog & this résumé

Bilingual (EN/VI) blog on Astro 6 · Tailwind v4 · Cloudflare Pages, including the page you're reading. Migrated from Hugo without losing a single URL; Lighthouse 100/100/100/100 across every route, view transitions, a hand-tuned glass mobile drawer, and AI-assisted SEO & image pipelines that keep both languages in sync.