← Owen Siregar

~/owen $ whoami --role developer

I build the systems payments run on

Backend developer behind QRIS, e-wallet, Virtual Account and card payment systems in C# .NET and SQL Server. For the past year I've been shipping full-stack with Next.js, React and TypeScript.

Get in touch →See the work
subscription payments processed every month
10,000+
fewer transaction errors on subscriptions
25%
payment methods behind a single link
4

// what I do

Payment integrations

QRIS (static and dynamic), e-wallets, Virtual Accounts and credit cards — including recurring billing and settlement.

APIs & data

Backend APIs in C# .NET on SQL Server, with LINQ and stored procedures where performance matters.

Full-stack with Next.js

App Router, React and TypeScript — from server components to the interface people actually click.

// selected work

  1. 01

    Recurring e-wallet billing

    Subscription Payments API

    An API that charges subscribers automatically on a schedule through e-wallet payment gateways.

    What I did

    • Designed the API that manages subscription payments
    • Integrated e-wallet payment gateways
    • Hardened transaction security and reliability

    Result

    • 10,000+ transactions processed per month
    • 25% fewer transaction errors
    • C# .NET
    • SQL Server
    • LINQ
    • Stored procedures
  2. 02

    One link, four ways to pay

    Payment Link

    Lets partners collect a payment from a single link — by Virtual Account, credit card, e-wallet or QRIS.

    What I did

    • Built the API that generates payment links
    • Integrated four payment methods behind one flow
    • Kept the flow secure and simple for partners

    Result

    • Higher payment conversion
    • More payment flexibility for partners
    • C# .NET
    • SQL Server
    • LINQ
    • Stored procedures
  3. 03

    QR payments wired into the cashier

    QRIS Generation & Transaction Reports

    Static and dynamic QRIS generation with real-time transaction reports, integrated with merchants' cashier systems.

    What I did

    • Built the API that generates static and dynamic QRIS
    • Built integrated transaction reporting
    • Helped merchants plug it into their cashier systems

    Result

    • Real-time transaction reports for merchants
    • A system merchants find easy to use
    • C# .NET
    • SQL Server
    • LINQ
    • Stored procedures
  4. 04

    From sign-up to live QR

    Merchant QRIS Onboarding

    An admin platform to register merchants' QRIS, activate it and track every registration's status.

    What I did

    • Built the merchant onboarding API
    • Built validation and the integration with the QRIS service
    • Streamlined registration to cut onboarding time

    Result

    • More efficient merchant onboarding
    • Smooth integration with QRIS payments
    • C# .NET
    • SQL Server
    • LINQ
    • Stored procedures
  5. 05

    Where did the money land?

    Settlement Report Dashboard

    A dashboard that shows settlement status across transactions and payments for admins and merchants.

    What I did

    • Built the API that collects settlement data
    • Built the interactive reporting dashboard
    • Kept the data accurate and fast to load

    Result

    • Clear settlement visibility for admins and merchants
    • Less time spent on manual reports
    • C# .NET
    • SQL Server
    • LINQ
    • Stored procedures
  6. 06

    Next.js, WebGL and custom shaders

    This website

    A Next.js App Router site where one 3D mesh morphs into a CPU, a compass, a camera lens and a beating heart.

    What I did

    • Built with Next.js, React and TypeScript
    • Wrote the GLSL shaders and morph targets by hand
    • Kept it accessible: reduced-motion support and a no-WebGL fallback

    Result

    • You're looking at it
    • Next.js
    • React
    • TypeScript
    • Three.js
    • GLSL
    See it on the home page →

// path

  1. Then

    Backend developer, payments

    Built payment infrastructure at Ezeelink in C# .NET and SQL Server — QRIS, e-wallets, Virtual Accounts, card payments, subscriptions and settlement.

  2. Now

    Full-stack with Next.js

    About a year of building with Next.js, React and TypeScript, bringing that backend discipline all the way to the interface.

// stack

Backend
C#.NETSQL ServerLINQStored procedures
Frontend
Next.jsReactTypeScriptCSS Modules
Payments
QRISE-walletVirtual AccountCredit card

Building something with payments or Next.js?

mowenbs@gmail.com