Hi, I'mLionael
Surya

Why I build

Details nobody sees.

Education

Selected work

Systems I've built.

Six featured systems, then the rest grouped by discipline. Every case study explains the engineering decisions behind the work — not just what was built, but why.

1. Next.js appApp Router · TypeScript
2. SupabasePostgres · auth
3. Project workflowskanban · tasks · docs
4. DeploymentVercel

Internal software · 2026

Aspen OS

The project operating system the QuickRN team actually runs on — tasks, kanban, documentation, and collaboration in one place. Built solo, in daily use at a nursing-education company.

Next.js · TypeScript · Supabase · Playwright · Vercel

Case study →Live ↗ — Aspen OSGitHub ↗ — Aspen OS

1. CSV importschema + referential checks
2. Multi-tenant dataPrisma · row-level isolation
3. Tax reference dataversioned · effective-dated
4. PPh 21 engineTER Jan–Nov · Pasal 17 Dec
5. Reports & payslipsCSV export · PDF

Payroll SaaS · 2026

Sakti 21

A multi-tenant PPh 21 payroll tax calculator serving 64 companies from one shared instance — Indonesian income-tax rules, bulk payroll imports, and PDF payslips in one system.

Next.js · TypeScript · PostgreSQL · Prisma · NextAuth · Playwright

Case study →GitHub ↗ — Sakti 21

Real-time data · 2026

Streaming Clickstream Pipeline

A real-time lakehouse for e-commerce clickstream — Kafka to Spark to Delta Lake to a live dashboard. Seven services, one command, exactly-once semantics.

Kafka · Spark · Delta Lake · DuckDB · Docker

Case study →GitHub ↗ — Streaming Clickstream Pipeline

1. FastAPIPydantic · extra=forbid
2. Historical contextPostgreSQL · strict < T
3. Feature engineeringserver-side · shared contract
4. Model + SHAPRandom Forest · TreeExplainer
5. Risk engineML 70% · rules 30%
6. Persistence & queueupsert · Streamlit

ML systems · API · 2026

FraudLens

A real-time fraud-scoring API that answers one question for an analyst — which transactions to investigate, and why — with leakage-safe features, SHAP explanations, and a hybrid ML-plus-rules risk engine.

FastAPI · PostgreSQL · scikit-learn · SHAP · dbt · Terraform

Case study →GitHub ↗ — FraudLens

AI engineering · 2026

IDX Stock Scanner

A daily decision-support agent for Indonesian equities: rules filter, an XGBoost model ranks, and an LLM explains. It now runs itself — scheduled scans, signal tracking against the index, and a gated challenger-model workflow.

Python · XGBoost · Claude API · GitHub Actions · Streamlit

Case study →GitHub ↗ — IDX Stock Scanner

Policy analytics · 2026

Nutrition Priority Index

A transparent, evidence-backed index ranking Indonesia's 38 provinces for child-nutrition intervention — built on real government data only, validated before published.

Python · GeoPandas · PySAL · Streamlit · pytest

Case study →Live ↗ — Nutrition Priority IndexGitHub ↗ — Nutrition Priority Index

Data Engineering

• Retail Sales ETL PipelineProduction-style batch ETL for a real retail dataset: validation, a star-schema warehouse, Airflow orchestration, and reruns that are safe by design.Python · Airflow · PostgreSQL→
• dbt E-Commerce Analytics MartA tested dbt project turning the real Olist e-commerce dataset into a single source of truth for revenue, customers, and product performance.dbt · PostgreSQL · SQL→
• Toronto Mobility IntelligenceA reproducible PostgreSQL + PostGIS platform that turns 20 years of Toronto's official collision data into findings a city team could defend — from Open Data to a Power BI dashboard.PostgreSQL · PostGIS · Python→

Machine Learning & Data Science

• Customer Churn PredictionAn end-to-end churn system for telecom: calibrated XGBoost, SHAP explanations, ROI-optimized thresholds, and FastAPI + Streamlit serving with drift monitoring.XGBoost · SHAP · Optuna→
• Retail Demand ForecastingSKU-level demand forecasting with honest evaluation: walk-forward validation across naive seasonal, Prophet, and XGBoost — beating the baseline before claiming anything.Prophet · XGBoost · pandas→
• FloodCast JakartaHyperlocal flood-risk early warning for 15 Jakarta neighbourhoods: calibrated multi-horizon XGBoost with SHAP explanations in Bahasa Indonesia and an offline map dashboard.XGBoost · Optuna · SHAP→

Client Software & Websites

Client website · 2025

Aspen Training Centre

Responsive marketing website for a Canadian vocational training centre — built with HTML, CSS, and JavaScript. No framework, no build step, no unnecessary complexity.

HTML · CSS · JavaScript · Responsive Design

Case study →Live site ↗ — Aspen Training Centre

Client website · 2026

Delta Harvest Festival

Heritage festival website for the Delta Mill Society — a two-day event site with programme details, venue histories, and ticketing. Built with HTML, CSS, and JavaScript.

HTML · CSS · JavaScript · Event Website

Case study →Live site ↗ — Delta Harvest Festival

Client website · 2026

Nel Coloma-Moya Portfolio

Academic portfolio for a human geographer and educator — a comprehensive personal site with biography, teaching experience, research, events, and publications. Built with HTML, CSS, and JavaScript.

HTML · CSS · JavaScript · Academic Portfolio

Case study →Live site ↗ — Nel Coloma-Moya Portfolio

Automation & Productivity

• Employee CV GeneratorDeterministic CV generation for a real HR team: pulls employee data from Drive and Sheets, fills a branded template, and exports PDF + DOCX — no code required by the user.Google Apps Script · Drive API · Docs API→

Research & Simulation

• Behind the FeedDoes personalized news exposure cost people diversity? A reproducible analysis of 8.6 million Microsoft News impressions for the TECHNATION Behind the Feed challenge, with Margil Parekh.Python · pandas · Jupyter→
• Elevator SimulationA discrete-event simulation answering a real capital question: how many elevators does a five-floor commercial building actually need — one, two, or three?Python · SimPy · NumPy→

Experience

The journey so far.

Four roles, most recent first.

1. Sep 2026 — presentToronto, Canada

   Career Peer

   Seneca Works, Seneca Polytechnic

   A part-time role in Seneca's career centre, helping students and alumni get their applications ready.

   • Review resumes and cover letters and give written feedback on clarity and accuracy.
   • Direct students and alumni to job-board access and career resources; support Career Threads workshops and events.
   • Keep student-support records up to date in SharePoint.
2. Jul 2025 — presentRemote

   Web Development and Data Operations

   QuickRN Canada

   QuickRN is a nursing-education company. I started on exam-prep content data and website support, then moved into building the team's software.

   • Built Aspen OS solo — the tasks, kanban, and documentation platform the team uses daily — with Supabase row-level security, versioned migrations, and Playwright end-to-end tests.
   • Delivered three production websites from concept to deployment, turning non-technical stakeholders' needs into requirements and maintaining each site after launch.
   • Maintain WordPress content, troubleshoot website and online-course access issues, and document each fix for customer inquiries.

   Building for real users meant working with non-technical stakeholders, figuring out what they actually need, and maintaining things after launch. That full cycle was valuable.

   Next.js · TypeScript · Supabase · Playwright · Vercel · WordPress

3. Aug 2025 — Sep 2026Toronto, Canada

   IT & Media Strategy Associate

   PERMIKA Toronto

   IT and media work for PERMIKA Toronto, a volunteer-run Indonesian student organization.

   • Built and maintained internal tools for event management and member engagement.
   • Led the social media campaign for League of Toronto 2026, the organization's annual event, coordinating a team of ten from planning through delivery.

   Working with volunteers taught me that leading without authority requires earning trust rather than relying on hierarchy.

4. Jun — Aug 2025Jakarta, Indonesia

   Software Engineering Intern

   CV. Veda Sakti Dharma

   My first internship: internal payroll software at a small firm.

   • Developed and tested a Python application that automates PPh 21 (Indonesian income tax) calculations and payslip generation.
   • Validated outputs against payroll records and debugged calculation issues before reporting; organized payroll data to make reporting more efficient.

   Payroll software needs to be correct every time. That was a good standard to learn early.

   Python

Skills

What I work with.

Grouped by the job to be done — nearly every tool here appears in a system above.

Social activities

Leadership before software.

The first systems I ran were made of people. These are the ones I'm proudest of.

Student council president

SMAK Penabur Summarecon Bekasi · 2023 — 2024

Led the student council through a full year of initiatives — the liaison between students, faculty, and administration. The council earned its Golden Flag certification with a near-perfect 248 of 251 score, and brought Easter to the children of Immaculatta orphanage.

Chief committee — SUBSCRIBE 6

LOSPELAGO festival · 2023

Directed the school's flagship event: a seven-day sport-and-art festival, from budget and logistics to delivering the opening speech — and playing the lead in the opening-night theatre performance.

Alumni visit organizer

SMAK Penabur Summarecon Bekasi · 2025

Co-led the school's alumni day from the other side of the world — managing the event's online operations from Toronto, connecting alumni with students preparing for university.

Resume

Different versions for different directions.

Seventeen variants of the same record, each written for a specific role. Preview any of them in full, then take the one that matches the job.