Open to AI-native engineering roles

Kelvin You

AI-native Full-stack Engineer

I build agents I don't trust — so they audit each other. Day job: payment flows that 9,000+ people move real money through.

How I Work

Payments taught me what it costs when a system is quietly wrong. I build agents like those stakes carried over.

9,000+
Users in production
4 agents
Debate pipeline, self-scored
RN + Kotlin
Front and back, shipped
Portrait of Kelvin You Kok Eng

Kuala Lumpur, Malaysia

Currently Building

A multi-agent stock-analysis pipeline on the Claude Agent SDK — four analyst agents, a debate stage, and an outcome-memory loop that scores its own past calls.

See the pipeline

Skills

Three layers, one glance. The marker says how far each has gone — filled means it ran in production for paying users.

●Shipped to paying users○Built in my own systems

AI systems

Personal-OS · ai-stock-analysis — public repos, weekly cadence, no paying users

  • LLM Integration (Claude API) — Built in my own systems
  • Claude Agent SDK — Built in my own systems
  • MCP (Model Context Protocol) — Built in my own systems
  • Multi-agent Systems — Built in my own systems
  • RAG — Built in my own systems
  • Prompt Engineering — Built in my own systems
  • Claude Code — Built in my own systems

Interface

dtcpay app · Simpletruss · Tencent / MiHoYo analytics dashboards

  • TypeScript — Shipped to paying users
  • React — Shipped to paying users
  • React Native — Shipped to paying users
  • Next.js — Shipped to paying users
  • GraphQL — Shipped to paying users
  • Apollo Client — Shipped to paying users

CourseworkFlutter

Server & data

dtcpay payments backend, Kotlin · PTIB, paid for by 3 centres

  • Kotlin — Shipped to paying users
  • PostgreSQL — Shipped to paying users
  • Supabase — Shipped to paying users
  • Python — Built in my own systems
  • Node.js — Built in my own systems
  • FastAPI — Built in my own systems

CourseworkJava · Solidity · Dask · scikit-learn · pandas

Ship & ops

  • Vercel — Shipped to paying users
  • Git — Shipped to paying users
  • Docker — Built in my own systems
  • GitHub Actions (CI/CD) — Built in my own systems
  • Playwright — Built in my own systems

CourseworkFirebase

Studied, never shipped

Go · Redis · AWS · Kubernetes— current learning target, kept off the resume

Projects

Each one with the measured result it produced — and an honest blank where there isn't one.

Agentic systems2026

Multi-Agent Stock Analysis

Four analyst desks — fundamentals, technical, sentiment, macro — each on its own MCP server, argued through a debate stage and merged by a synthesizer. Signals are validated walk-forward against a frozen holdout, with Wilson intervals and a deflated Sharpe on the strategy search — which is how I know the factor still lagged buy-and-hold.

Python · Claude Agent SDK · MCP · RAG · Multi-agent Systems · Walk-forward Backtesting · Pydantic · FastAPI

1.32
Sharpe on a frozen 2023-26 holdout, net of cost
10/12
tickers still net-positive at 30 bps/side
Source

2026

Personal-OS

Guardrail design over raw model output. Only an acute bad-sleep night is non-overridable; on the noisier 7-day trend, live HRV overrides the automated deload — so it catches real risk without crying wolf every week on a lagging metric.

Claude Code · MCP · LLM Integration · Multi-agent Systems · Python · TypeScript · Agent Skills

12
agent skills running on a weekly cadence
1
non-overridable rule; the rest defer to live HRV
Source

2025

PTIB

Multi-tenant SaaS that digitised a 200-student tuition centre: role-based portals, Stripe billing, QR attendance, row-level security in Supabase.

Next.js · TailwindCSS · Supabase · PostgreSQL · Stripe · Shadcn · React

$500
MRR from 3 pilot centres
5 hrs
of admin saved per week
Demo
All 8 projects

Experience

From production fintech platforms to agentic systems I build on my own time.

2025

NOW

1 yr 2 mos

Full-timeKuala Lumpur, Malaysia

Frontend Engineer

DTCPay (FinTech)

Production payments platform, 9,000+ users. Led Flutter to React Native migration unifying mobile + web.

  • Kotlin backend for cross-currency batch payments: FX quote lock, largest-remainder allocation, CAS-on-status duplicate guard.
  • Fail-closed PII masking across 5 payment surfaces — unmask only on explicit corporate classification.
  • KYT case review UI: maker-checker approval workflow, RFI state machine, scope-gated decisions.

Kotlin · React · React Native · TypeScript · Payment Systems · Concurrency · System Design · Fintech

Wrote about this16

The Status Column Is the Lock: Duplicate-Submit Protection Without an Idempotency KeyMaking the Rows Add Up: Rounding in a Cross-Currency Batch PaymentFail-Closed: Picking the Conspicuous Failure Over the Silent OneFour Eyes, One Status Column: Modelling a Maker-Checker Review WorkflowNo Test Runner: Verifying a Migration by Triangulating Three Blind Tools
11 more
545 Migrations in a Shared JARChecking Idempotency Against the Wrong ClockThe Update That Reverted Someone Else's UpdateThree Copies of the Same Rule, Three Different Answers for ZeroThe Guard Kept Running, It Just Stopped Being Able to FailThe Flag Meant 'Done', But 'Done' Hadn't Happened YetDisabling It Did Nothing, Because 'Off' and 'Never Set' Looked the SameThe Permission Check That Was Right for the Old CallerA Cache Rebuild Looked Exactly Like a New LoginThe Merge Conflict That Compiled Clean and Broke at RuntimeComputed Once, Wrong Forever

2024

2025

1 yr 1 mo

Full-timeKuala Lumpur, Malaysia

Frontend Engineer

Simpletruss

Building enterprise property management SaaS. 500+ properties, 10K+ maintenance tickets monthly.

  • Component library with compound patterns, TypeScript generics, Storybook docs. 40% faster dev velocity, 60KB bundle reduction.
  • GraphQL layer: Apollo Client, 80% cache hit rate, custom hooks (usePaginatedQuery, useOptimisticMutation). Type-safe, zero prop-drilling.
  • Performance: Code splitting, virtualization for 10K+ rows, Zustand over Redux. 35% faster initial loads.

React · TypeScript · GraphQL · Apollo Client · Zustand · Material UI · Storybook

LessenPro

Demo

Scheduling engine, vendor coordination, maintenance tracking. 500+ properties managed.

React · TypeScript · GraphQL · Material UI · Apollo Client

Wrote about this1

The Cache Doesn't Know About Your List: Apollo Normalization in Practice

2023

2024

10 mos

Full-timeKuala Lumpur, Malaysia

Frontend Developer

Beyondsoft (Tencent)

Analytics platform for Tencent, MiHoYo (Genshin Impact), major game studios. Millions of events/day.

  • Performance: Virtual scrolling (500K rows), Web Workers for parsing, debounced filters. Sub-3s loads at 60fps.
  • Quality: Jest standards, mandatory reviews, 40% fewer production bugs. Docker dev env: 4h → 30min onboarding.
  • Cross-team: Specs with Tencent engineers, cross-browser (Safari, IE11), China CDN optimization.

React · TypeScript · Redux · Ant Design · Jest · Docker · Webpack · Go

Databrain Global

Demo

Real-time player analytics. 100K+ row datasets, complex filters, interactive dashboards.

React · Umi.js · Ant Design · TypeScript · Go

Wrote about this1

Every Boundary Leaked: A Year of Micro-Frontends at Tencent Scale

2023

2023

6 mos

InternshipKuala Lumpur, Malaysia

Java Engineer Intern

Finexus (Fintech)

First exposure to fintech production payment systems — legacy Java/JSP monolith, thousands of daily transactions. Foundation for current fintech work at dtcpay.

  • Fixed connection pool bug causing peak-hour failures. HikariCP + JMX monitoring → 99.9% uptime.
  • Deployment automation: Bash scripts for Tomcat WAR deploys. 4h → 2h per release.
  • Jasper Reports: Query optimization, indexing. 8s → 1.2s report generation.

Java · Oracle SQL · Servlets · JSP · Tomcat · Shell Scripting · Jasper Reports

Wrote about this1

The Pool Wasn't Out of Connections, It Was Out of the Right Ones

2020

2021

4 mos

InternshipKuala Lumpur, Malaysia

Blockchain Engineer Intern

Techtics (Web3)

Ethereum dApp during 2020 DeFi boom. Smart contracts, gas optimization, MetaMask.

  • Solidity contracts: Reentrancy guards, gas estimation UI, MetaMask signing. Deployed to mainnet.
  • Gas optimization: IPFS storage, batched transactions. 65K → 38K gas (40% savings).

React · TypeScript · Solidity · MetaMask · Node.js · Express · Redux

Wrote about this1

The Guard That Protects You Is Also the Guard You're Paying For

Education

Two credentials, one institution, four unbroken years. Certificates and transcripts are on file.

Tunku Abdul Rahman University of Management and Technology

Kuala Lumpur, Malaysia2019 – 20234 yrs 2 mos unbroken

3.72

CGPA

Dean's List

top 10% of cohort

CertificateTranscript

Bachelor (Hons)2021 – 2023

Software Engineering (Honours)

Distributed systems, parallel computing and performance optimization, carried through 15+ builds — blockchain dApps, mobile apps, graphics.

  • Final year project — an offline-first travel guide app, built as a two-person team
  • Earned the Finexus (fintech) internship on university recommendation
Core
Data Structures & Algorithms · Distributed Systems · Parallel Computing · Human-Computer Interaction · Graphics Programming
Electives
Mobile Development (Flutter) · Blockchain Development (Solidity) · Data Science (Python)

3.7439

CGPA

Transcript

Diploma2019 – 2021

Computer Science

Where the fundamentals came from: object-oriented Java, then down to C and assembly, against a full mathematics track.

Core
Object-Oriented Programming (Java) · C & Assembly · Algebra · Calculus · Statistics · Discrete Mathematics
Kuala Lumpur · GMT+8Replies within a dayOpen to conversations

Start a thread

Email's the fastest route to me. Pick a subject and the draft below lands in your mail client, already written.

Toykekelvin0220@gmail.com
Re

Hi Kelvin — we're hiring a full-stack engineer and your payments work looks like a fit. Here's the team and the scope —

Open in mail client
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