Android Engineer · Jakarta, Indonesia

Building Android apps
people rely on every day.

I'm William — an Android Engineer with 7+ years of experience shipping high-quality mobile applications across e-ticketing, fintech, banking, and music streaming. Native Android (Kotlin/Java) specialist with cross-platform experience in Flutter.

Download CV (PDF) See my work

7+: Years of experience
11+: Apps built & shipped
3: Industries served
6: Engineers led

About

Analytical engineer, pragmatic shipper.

I specialize in Native Android (Kotlin/Java) and have cross-platform experience with Flutter. I'm known for strong analytical and debugging skills, with a proven track record of improving stability, performance, and user experience.

I care about writing clean, maintainable code and collaborating closely with product and engineering teams to deliver impactful mobile solutions.

Get in touch

Skills

What I work with.

Core

Native Android (Kotlin)
Java
Flutter
Mobile development
App size reduction

Architecture

MVP
MVVM
Dependency Injection (Koin)
Technical debt & code refactor
Code review

Quality & Testing

Unit testing (JUnit)
UI testing (Espresso)
Bug-fixing
Crashlytics monitoring
Complex problem solving

Security

Encryption
ProGuard
Penetration testing (Frida, jadx)
App hardening

Languages: Indonesian (native) · English

Experience

Where I've worked.

Sep 2022 — Dec 2025 · 3 yrs 4 mos

Android Engineer

TIX ID · PT Nusantara Elang Sejahtera
- Developed several TIX ID features for Indonesia's leading cinema ticketing app
- Built TIX Mini from scratch using Flutter
- Handled TIX Events merchant offline cashless app
- Maintained app security and wrote technical documentation
- Monitored Crashlytics and app reviews; fixed crashes and maintained tech debt
Dec 2020 — Sep 2022 · 1 yr 10 mos

Android Developer Lead

PT MNC Bank Internasional, Tbk
- Developed several Motion Banking features and improved app security
- Improved the code structure and team development behavior
- Led a team of 6 engineers and the Android team's biweekly standups
- Mentored junior developers and wrote technical documentation
Jul 2018 — Dec 2020 · 2 yrs 6 mos

Android Developer

PT Code Development Indonesia
- Built, updated, and patched client Android applications across fintech, sales force, music streaming, and marketplace products