// JUNXIONG.DEV / SINGAPORE
Ong Jun Xiong
AI infrastructure engineer at TikTok in Singapore. I build backend systems for production AI, and a lot of small tools nobody asked for.
Agent runtimes, tool servers, data products, and the occasional two-day experiment. Some of it is work. Most of the rest started because something annoyed me enough to write code about it.
JX / 2026
SINGAPORE
// PROJECTS
Stuff I built
Open source · 2026
Python
A deterministic boundary for agent output. Tool results become typed facts, and any ranking, total or relationship those facts do not support gets blocked before it reaches the user.
groundplane / boundary.py
169 tests
reg.record_ranking("campaign_ctr", rows, key="ctr", ...)
with boundary(reg, facts=[...], checks=[superlative(...)]) as b:
b.submit({"winner": "north"})
UnsupportedClaim: registered facts support 'harbour'
Argmax
Order
Aggregate
Entity
Row
Personal tool · 2026
Data + agents
Scores Singapore property listings against official transactions, cost models and agent research. I built it because comparing units by hand in a spreadsheet was miserable.
Sample report
Comparable unit
relative value
78%
liquidity
64%
hold fit
86%
Company · 2025
Sold to a client
A one-person AI studio I ran alongside TikTok. I did the selling and the pricing, built the document-grounded assistants, shipped them, and then sat with clients until they could use the thing without me.
knowledge
LlamaIndex
service
FastAPI
interface
Next.js
Two-day hackathon · computer vision
Chrome extension that pauses and seeks YouTube with hand signs.
2021 – 2023
Older projects
2023
Interview practice with a collaborative editor, built as a distributed system.
2021
Gamified, accessible learning platform. Our NUS Orbital project.
// NOW
At work
I build shared AI infrastructure at TikTok in Singapore: an A2A and LangGraph runtime, a Go MCP server, a React chat SDK, and the backend systems around them.
Work history →Away from work
Tennis, a trading journal I actually keep up, and far too much reading about home-server hardware I have not bought. I also build small tools for decisions I would otherwise wing.
Hobbies →