# Ong Jun Xiong

> Ong Jun Xiong is an AI infrastructure engineer at TikTok in Singapore. See his agent systems, open-source tools and personal software projects.

Software engineer at TikTok in Singapore, building AI infrastructure for e-commerce. Before that, Go services for TikTok's seller platform. Founded and ran Compoze alongside TikTok in 2025 until a client bought it. Studied computer science at the National University of Singapore, including NUS Overseas Colleges in Munich.

Contact: email via https://junxiong.dev/contact. GitHub: https://github.com/ong6. LinkedIn: https://www.linkedin.com/in/junx6/.

## Work history

- [Resume](https://junxiong.dev/resume): roles, teams, dates and skills; mirrors LinkedIn
- [Resume PDF](https://junxiong.dev/resume/Ong-Jun-Xiong-Resume.pdf): one-page print version

## Projects

- [Groundplane](https://junxiong.dev/groundplane): open-source Python library that checks declared fields in agent output against recorded tool facts, with deterministic checks and errors that include provenance. Code: https://github.com/ong6/groundplane
- [Compoze](https://junxiong.dev/compoze): document-grounded assistants for businesses, built and run solo in 2025; a client bought the company at the end of that year
- [Trading engine](https://junxiong.dev/trading-engine): paper-trading research engine run nightly on real US market data, with pre-registered strategies and a fill model that cannot see the future. Code: https://github.com/ong6/trading-engine. Earlier versions, each with its own diagram: https://junxiong.dev/trading-engine/v1 to /v5
- [Skillsmith](https://junxiong.dev/skillsmith): makes an agent skill from a repo and keeps it only when it beats a no-skill baseline on heldout tasks. Code: https://github.com/ong6/skillsmith
- [Skillpack](https://junxiong.dev/skillpack): Claude Code and Codex skills shared across repos as a two-way git subtree. Code: https://github.com/ong6/skillpack
- [Jobforge](https://junxiong.dev/jobforge): Claude Code plugin for coding-interview prep that grades the plan said out loud. Code: https://github.com/ong6/jobforge
- [UI Pack](https://junxiong.dev/uipack): shared web figures, motion and slide starters used across these projects. Code: https://github.com/ong6/uipack

## Writing

- [Notes](https://notes.junxiong.dev): longer working notes on AI systems and projects

## Optional

- [Hobbies](https://junxiong.dev/hobbies): coding and AI, tennis, trading, home servers, travel, reading
- [Archive](https://junxiong.dev/works): university-era projects, 2020 to 2023