Available for consulting work

Agastya Darma

Software EngineerTokyo, Japan

Building mobile commerce at Mercari US. Crafting high-performance, design-centric React Native apps.

Selected Work

Current Role
Mercari US logo

Mercari US

Software Engineer Tokyo, Japan
July 2025 - Present

Designing scalable React Native architecture, establishing foundations, and driving technical decisions for high-performance mobile commerce experiences serving millions of users in the US marketplace.

20+ Million Downloads
Play StoreApp Store
React NativeTypeScriptReduxExpoGCP

Highlights

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Previous Experience
Ruangguru logo

Ruangguru

Engineering Manager Jakarta, Indonesia3.5 years
November 2021 - June 2025

Leading the Mobile Platform Team, enhancing performance and scalability of React Native hybrid and native iOS/Android apps across key products including Ruangguru (K-12 learning), Roboguru (AI tutoring), SkillAcademy, RuangKerja, and English Academy. Previously led development of universal frontend architecture with React Native and Tamagui, achieving 50% faster build times and 60% improved app startup.

20+ Million Downloads
Play StoreApp Store
React NativeTamaguiSwiftKotliniOSAndroidLeadership
Kumparan logo

Kumparan

Software Engineer Jakarta, Indonesia3.5 years
May 2018 - November 2021

Migrated mobile site from Redux Saga to Apollo GraphQL, created cross-platform Kumparan UI Kit for React and React Native, and rewrote mobile app with React Native, Apollo, and GraphQL. Achieved faster load times, seamless Cordova integration with zero downtime, and increased daily active users.

1+ Million Downloads
Play StoreApp Store
React NativeGraphQLApolloReactCordovaRedux
Tech Evangelism

Developer Circle Leads

Facebook Developer Circles Program

September 2017 - November 2021

4+ years

In my role with the Developer Circles from Facebook program, I introduce and promote Facebook's latest APIs and core system frameworks that power the platform experiences on Facebook, Instagram, and WhatsApp. I also help developers adopt Facebook's open-source technologies such as React, React Native, and Relay. By leading workshops and community events, I ensure developers can leverage these tools to build impactful, scalable solutions.

ReactReact NativeRelayGraphQLCommunity BuildingTechnical Workshops
My Values

Building for
Sustainable Impact

At Mercari, I work on technology that extends the lifecycle of goods. Every feature I build helps reduce waste and creates value in the circular economy— from Tokyo to the world.

Millions

Users Empowered

Sustainable

Tech for Good

ROPPONGI, TOKYO

Open Source & Writing

I believe in democratizing knowledge. I contribute to the React Native ecosystem and write technical deep-dives on performance and architecture.

GitHub Read Articles