Portfolio · Antoni Wijaya
Selected work from 6 years of shipping software at national scale.
GoPay Merchant
GoTo Group · Senior Software Engineer · 2021 to 2025
Merchant fintech app at national scale, built in Flutter.
500,000+ active merchants · 70% less regression testing
Problem
GoPay Merchant is the app 500,000+ active merchants use to take payments. At that scale a bad release or a wrong payment status costs merchants real money, so shipping fast had to go hand in hand with shipping safely.
What I built
A mobile automation test suite with Flutter Integration Test and Patrol, running on BrowserStack in GitLab CI/CD. BLoC state management that cut crashes, watched in Crashlytics. Webhook-based payment status reconciliation with Midtrans, with idempotency and a polling fallback. In-app KYC and lending verification through a WebView bridged to Flutter. I also ran Play Store and App Store releases and mentored junior and mid-level engineers.
Result
Regression testing time down 70%, and crash-free sessions kept consistently high across releases of a national-scale fintech app.
Flutter, Dart, BLoC, Patrol, Midtrans, GitLab CI/CD
AI & Automation
Independent · 2026
WhatsApp ordering bots and workflow automation for small Indonesian businesses.
Problem
A building-materials distributor took every order by hand on one WhatsApp number, with prices and stock in a spreadsheet and three price tiers (grosir, eceran, reseller) to get right on every quote.
What I built
A WhatsApp ordering bot on the official WhatsApp Cloud API and self-hosted n8n. It reads free-text orders in Bahasa Indonesia, including units like sak and dus, quotes the right tier price with a margin floor, and runs each order from draft to confirmation, payment, and stock update. Prices come live from the store's own Google Sheet. An ops dashboard lets the owner approve orders, track credit, print receipts, and hand unclear messages to staff. Prices, stock, and payments stay rule-based by design: no AI guessing on money.
Result
Deployed as a pilot with one store, designed to take over most of the order desk while the owner approves every order.
n8n, WhatsApp Cloud API, Google Sheets, Python, Docker
Halocoko
Client · Built the full site · WordPress · Oct 2026
Bilingual brand website for Halocoko, an Indonesian chocolate ice cream brand.
Problem
Halocoko needed a brand website to show its ice creams, share its story, and bring in new partners, in Bahasa Indonesia and English.
What I built
A WordPress site on a custom Hello Elementor child theme, built with Elementor Pro and translated with Polylang. Product pages for the ice cream range, the brand's journey and awards, an inspiration hub for partner stories, activities and campaigns, a news section, and Become a Partner and contact pages. Google Site Kit connects Search Console and Analytics.
Result
Live at halocoko.com in Bahasa Indonesia and English.
WordPress, Elementor Pro, Hello Elementor child theme, Polylang, Google Site Kit
Vegigo
Founder · Built solo · 2026
Community-verified restaurant finder for vegetarian, vegan, halal, and gluten-free diets.
5,000+ places listed · 4 countries
Problem
A star rating tells you the food was good, not whether the broth uses meat stock or whether vegetarian means no eggs. For strict vegetarians, and for Jain, halal, or allergy diets, the reliable answer comes from other diners. Existing apps had thin, outdated coverage in Indonesia and no way to verify dietary claims.
What I built
The whole product, solo and part-time: a Flutter app for iOS and Android, a Node.js API, and a Next.js site with SEO restaurant pages and an admin panel, all on Firebase. Diners verify dietary tags and every place gets a verdict against your own diet rules. Plus a trust score that resists farming, Local Guide roles, a community feed, restaurant claims, rewards, and an Ask AI recommender built on Claude.
Result
Live on the App Store and Google Play with 5,000+ places listed across 4 countries, starting with Indonesia and Taiwan.
Flutter, Riverpod, Node.js, Next.js, Firebase, Claude
Miledadao Music
Founder · Private build · 2025 to 2026
Devotional music player for a faith community, on iOS, Android, CarPlay, and the web.
113 songs · 3 languages
Problem
A community with songs in Chinese, English, and Indonesian needed one place to listen, including offline and on the road, instead of scattered audio links.
What I built
An Expo and React Native app for iOS and Android plus an installable Next.js PWA, with song data in Firebase. Background playback, shuffle and repeat modes, a queue, full-screen lyrics with pinyin, playlists, offline downloads that recover when the network drops, CarPlay, and shareable links to any song.
Result
113 songs across three languages, built for the community's private use. Not publicly released.
Expo, React Native, Next.js PWA, Firebase, CarPlay
Jejakku
Founder · Mar to Aug 2026
Trail discovery and GPS hiking app for Indonesia.
Problem
Urban hikers in Jakarta, Bandung, and beyond struggled to find reliable, local trail information in Bahasa Indonesia. International apps like AllTrails and Komoot had little Indonesian trail data.
What I built
A Flutter app with trail discovery, map explore, live GPS tracking, trail logs, challenges and badges, a community feed, live location sharing with family, and a Jejakku Plus subscription. A Next.js website in Bahasa Indonesia with a trail directory, maps, and a blog, plus an admin dashboard, all on one Supabase backend.
Result
Reached version 1.0.4 between March and August 2026, then shut down.
Flutter, Supabase, Next.js, RevenueCat, Leaflet