Open to senior backend & full-stack roles· AU / NZAustralia / New Zealand

I make money move safely,queries run fast,and AI agents behave.

Lucas Sim, backend engineer, 8+ years. Now at YTL AI Labs.

See the proof

Résumé PDF

system maphover a node

~0×
faster heavy queries
5–6
person team led to launch
0M
rows migrated live

Shipped at

YTL AI Labs
GXBank
Skribble Lab
qBayar

Kuala Lumpur --:--

Known for

Query performance
Team leadership
High-concurrency Go
Race conditions
Zero-downtime migrations
MCP + guardrails
Payments

Go
PHP · Laravel
Python
PostgreSQL
Redis
AWS
Kubernetes
Docker
CI/CD

01About

Illustration of Lucas in headphones, sipping from a mug with a code icon on it

I'm Lucas. Eight years of backends: a digital bank, a 0‑to‑1 SaaS I led, and now MCP tooling at YTL AI Labs. I like the parts nobody sees. Next chapter: Australia or New Zealand.

Illustration of Lucas coding on a laptop, with books on Go and Postgres on the desk — 01 / 04

Illustration of Lucas in a cap, holding a tennis racket and a ball — 01 / 04

02Proof

01 / 07Scroll →

Specialty · PerformanceYTL AI Labs
2 min → <10 s
Heavy platform queries
Specialty · LeadershipSkribble Lab
Team of 5–6
Zero to launch in ~12 months
03YTL AI Labs2026
20M rows
Migrated live, zero downtime
04GXBank2026
Redis mutex
Onboarding race, fixed
05YTL AI Labs2026
agent
guardrails
mcp
1. › grafana.get_dashboard("payments")✓ allowed · read
2. › datadog.query_metrics("p99 latency")✓ allowed · read
3. › ops_portal.run_action("rerun_report")✓ approved action
4. › db.execute("DROP TABLE users")✗ blocked · behavioural boundary
MCP + guardrails
Agents with boundaries
06GXBank2026
Hotspots
Redis hash slots, rebalanced
07qBayar2021 — 2023
1 login
SSO with QR sign-in

03Career

Jul 2026 — Present · AI platform

2 min → <10 s

heavy platform queries

Built MCP for the internal operational portal so teammates can pull data and run approved actions through an agent instead of only using the UI.
Wired existing market MCP servers into day-to-day workflows (credentials based) for tools such as Datadog, Grafana, GitHub, and cloud systems.
Designed guardrails for agent workflows beyond simple permission checks, including behavioural boundaries for safer production use.

Jan 2026 — Jul 2026 · Digital banking

Race condition

fixed in onboarding with a Redis mutex

Built and maintained high-concurrency backend microservices in Go for digital banking services designed for high availability and high-volume financial traffic.
Resolved a critical race condition in the onboarding flow using Redis-based mutex locking.
Optimised Redis hash slot distribution to reduce hotspotting as traffic grew.

Sep 2023 — Jan 2026 · SaaS · edtech

Team of 5–6

led from zero to launch in ~12 months

Promoted to Lead Developer for Skribble Learn. Owned solution architecture, infrastructure planning, and mentorship for a team of 5 to 6.
Shipped the Skribble Learn platform within about 12 months, with major gains in processing speed and usability versus legacy systems.
Built CI/CD from scratch and pushed a testing culture (PHPUnit, high coverage targets) to support safer releases.

Apr 2021 — Sep 2023 · Fintech · payments

1 login

SSO with QR sign-in across products

Built a centralised Identity Server (SSO) and auth package, including QR-based login across products.
Led legacy migration from Yii1/Zend to Laravel, improving release speed and reducing technical debt.
Created a reusable API wrapper package that cut third-party integration time for the team.

Nov 2018 — Sep 2020 · Fintech · payments

RHB H2H

payment gateway integration, led

Led RHB Host-to-Host payment gateway integration and related finance automation workflows.
Built petty cash claims with RHB payouts and led purchase/inventory tracking systems.

04Projects

P/01A Mac database app in Rust

InletDB

Keyboard-first Postgres and SQLite. One round trip per query, a safe mode for risky writes, and a guarded MCP server for agents.

Rust
Tauri 2
PostgreSQL
MCP

Website Private alpha · macOS

InletDB · shop-eu

Query 1customers⌘K

1-- Customers who paid this week

2SELECT c.id, c.email, c.plan, i.paid_at

3FROM customers c

4JOIN invoices i ON i.customer_id = c.id

5WHERE i.paid_at > now() - interval '7 days'

idemailplanpaid_at

10482aisyah@example.compro10-06 09:41

10477wei.jie@example.comteam10-06 09:12

10455priya@example.compro10-05 22:03

10431daniel@example.comfree10-05 17:48

10419hana@example.comteam10-05 11:26

10398arjun@example.compro10-04 20:15

10376siti@example.compro10-04 08:57

10351marcus@example.comteam10-03 19:30

10327nur@example.comfree10-03 07:04

10302kai@example.compro10-02 16:22

UPDATE on customers isn't run yet

No WHERE: this changes every row in customers (about 48,213).

prd · shop-eu / shop · Confirm writes is on

Cancel escUpdate all rows ⇧⌘↵

✓ Nothing ran. Nothing changed.

connected · warm1,284 rows · 52 ms

run

Commands

Run statement ⌘↵

Run all statements ⇧⌘↵

P/02Semantic search, visible

RAG Playground

A recruiter query, embedded, matched against 50 profiles in pgvector, answered by a streaming LLM.

Go
Encore
pgvector
Gemini

Read the case study Live demo Code

rag-playground.lucascodes.dev

P/03Money moving, in real time

WebSocket Transaction Visualizer

Every step of a bank transfer, from balance check to confirmation, streamed live over WebSocket.

Go
Encore
WebSocket
PostgreSQL

Read the case study Live demo Code

webhook-playground.lucascodes.dev

P/04A Claude Code plugin

Claude Usage Mod

Context and rate limits above the Claude Code prompt, watched by a pixel crab whose mood follows the highest one.

Unofficial fan project, not affiliated with Anthropic.

TypeScript
Claude Code
SVG

Website Code

Claude Code · payments-api

05Contact

Next stop: Australia or New Zealand.

Email

Email me

GitHub

Résumé PDF

Malaysian citizen · needs AU / NZ sponsorship · ready to relocate

KUL · home

Route

KUL→SYD6,620 km

Kuala Lumpur

--:--

Sydney

--:--

I make money move safely,queries run fast,and AI agents behave.

Proof, in motion.

Heavy platform queries

Zero to launch in ~12 months

Migrated live, zero downtime

Onboarding race, fixed

Agents with boundaries

Redis hash slots, rebalanced

SSO with QR sign-in

Eight years, one changelog.

InletDB

RAG Playground

WebSocket Transaction Visualizer

Claude Usage Mod

Next stop: Australia or New Zealand.Next stop:Sydney.

Next stop: Australia or New Zealand.