// JUNXIONG.DEV / SINGAPORE
Ong Jun Xiong
AI infrastructure engineer at TikTok. I make reliable systems and small tools for problems I cannot leave alone.
Most of my work sits somewhere between backend infrastructure and the people using it: agent runtimes, tool servers, data products, and the occasional two-day experiment. This is where I keep the things I have made.
JX / 2026
ENGINEER + BUILDER
// SELECTED PROJECTS
Things I have made.
Open source · 2026
Python
A small deterministic boundary for agent output. It turns tool results into typed facts, then rejects rankings, totals, and relationships the model cannot support.
groundplane / boundary.py
93 tests
facts = FactSet.from_tool_results(rows)
claim = Winner(entity="north")
boundary.verify(claim) → UnsupportedClaim
output blocked ✓
Argmax
Order
Aggregate
Entity
Row
Personal tool · 2026
Data + agents
I wanted a calmer way to evaluate Singapore homes, so I built one from listing data, official transactions, cost models, and structured agent research.
Sample report
Comparable unit
relative value
78%
liquidity
64%
hold fit
86%
Company · 2025
Acquired
Compoze
A one-person AI studio I ran alongside TikTok. I found the customers, priced the work, built their document-grounded assistants, deployed them, and taught people how to use them.
knowledge
LlamaIndex
service
FastAPI
interface
Next.js
Two-day hackathon · computer vision
A Chrome extension that lets you pause, seek, and control YouTube with hand signs.
Older, still mine
From the archive
2023
A collaborative interview-practice platform built as a distributed system.
2021
A gamified, accessible learning platform made for NUS Orbital.
// 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
I play tennis, keep a written trading journal, overthink home-server hardware, and build software for decisions I would otherwise make badly.
The non-work page →