Hoang Yell

Paradox.ai (Olivia) — Senior Software Engineer

Da Nang, Vietnam · Sep 2018 – Present · Occasional onsite, Arizona, USA

• Architect of the ATS integration framework that plugs Paradox into enterprise ATS partners. Traffic grew ~360% YoY while keeping the same SLA and shipping zero highest-priority production bugs; the reusable boilerplate I designed is now the default starting point for new partner onboardings.
• Led the company-wide logging migration off RDS / NoSQL to an AWS data lake (Kinesis → Firehose → S3 → Glue, Parquet + JSON tables, union views) — adopted across other teams as the standard logging blueprint.
• End-to-end owner of the webhook + audit subsystem: architecture, primary reviewer, on-call. Added log enrichment, log-id correlation, and rerun tooling for ops.
• Built an internal Postman-like asynchronous request runner for large-scale API workflows — shifted integration work from devs to specialists for Compass Group, 7-Eleven, McDonald's, ADP, and other Fortune-500 clients.
• Proactive observability with Datadog, Sentry, and Slack alerts; caught and mitigated a major queue incident before it escalated.
• Quality & mentorship: drove the test-suite migration to Pytest and zero-production-bug sprints (consistent A / A+ release quality); hosted internal knowledge-sharing sessions on AI-assisted dev (Cursor / Claude / Copilot) and led PR-review culture across INT/US time zones.

Fiverr — Freelance Backend Engineer

Remote · 2021 – 2022

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

FPT Software — Software Developer

Da Nang, Vietnam · May 2017 – Sep 2018

• 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.

GOSU Online Corporation — Part-time Developer

Hue, Vietnam · Jan 2016 – May 2017

• 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 & Mock Webhook API

Browser-based developer utility that repairs broken JSON / XML / YAML / CSV with 29 documented auto-fix passes, converts across formats, lets users publish any payload as a live REST endpoint, and dispatches HTTP requests with saved templates. Built on React 19 · Next.js 16 · Cloudflare Workers with edge KV for the mock-webhook log portal. Includes JMESPath search, multi-view (tree / graph / table) visualiser, Monaco diff, and cross-device cloud backup.

markdy.com — Open-source animation DSL engine

"Like Mermaid, but for motion." A framework-agnostic animation DSL with a zero-dependency TypeScript parser (@markdy/core, ~12 KB), a Web Animations API renderer (@markdy/renderer-dom, ~22 KB), and an Astro island (@markdy/astro, ~2 KB). Designed to be AI-agent-friendly — ships an AGENT.md so LLMs can generate, validate, and iterate scenes.

@hoangyell/gallery — Astro image gallery on npm

Published npm package for Astro: lightbox, pyramid multi-row layout, full keyboard / accessibility support. Extracted from this blog after the third copy-paste — shipped as a reusable component instead.

chat.hoangyell.com — Real-time chat on the edge

Real-time chat over native wss:// to a Cloudflare Worker + Durable Objects. Password-protected rooms, presence, drag-and-drop file uploads, dark/light glassmorphism UI. Next.js 16 · React 19 · TypeScript, WCAG 2.1 AA, GPU-only animations to keep Lighthouse green.

hoangyell.com — Personal blog (this site)

Bilingual (EN/VI) blog on Astro 6 · Tailwind v4 · Cloudflare Pages. Migrated from Hugo without losing a single URL. Lighthouse 100/100/100/100, view transitions, premium glass mobile drawer, AI-assisted SEO & image pipelines.

hn.hoangyell.com · repo.hoangyell.com — Bilingual content pipelines

Two sister blogs (HN stories and GitHub repos) that retell source material in EN + VI. Same Astro engine, AI-driven /new-post Cursor skill that fetches the upstream source, drafts bilingual MDX, validates SEO, and commits — all guarded by Lighthouse CI gates.

bulk-webp-url-replacer — Python image ETL on PyPI

CLI + library that extracts image URLs from markdown (frontmatter, galleries, inline), downloads in parallel, converts to WebP at custom quality / dimensions, and rewrites the markdown to point at a CDN prefix. Dry-run mode, skip already-processed assets, used to migrate this entire blog.