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Rhony Abdullah Siagian
From Indonesia 10:07 PM (GMT+07:00)
$15/hr or $22,800/yr

Active 5 days ago


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Senior Android Engineer

Cross-Platform Mobile Developer
Available for hire
Years of experience
10+ years
Experience level
Senior
Available for
Full-time, Part-time, Contract, Freelance
Available from
26 Jun 2026
Download Resume / CV

My Story: What Makes Me Unique

I am Rhony, a seasoned Android Engineer with 10 years of experience in designing and delivering scalable, high-performance mobile applications for fintech, retail, health tech, and e-commerce industries. What makes me unique is my blend of technical mastery, leadership, and a relentless focus on security and performance. I don’t just build apps. I solve complex challenges, lead teams, and create solutions that drive real business impact.

My journey in mobile development began a decade ago, and over the years, I’ve grown into a technical leader who thrives in fast-paced, collaborative environments. I’ve led teams of 5+ engineers, mentored developers, and contributed to high-traffic platforms used by thousands. My expertise in optimizing performance, implementing robust security, and deploying seamless user experiences has been a cornerstone of my career.

What truly sets me apart is my commitment to innovation and continuous growth. I stay ahead of industry trends by integrating cutting-edge tools and architectures like Jetpack Compose, modularization, and AI-driven development into my work. My deep knowledge of mobile security (OWASP MAS, cryptography, Play Integrity API) has reduced mobile fraud by 95% in previous roles, ensuring the apps I build are secure, reliable, and compliant.


My Experience: A Decade of Impact

Over the past 10 years, my career has been defined by leadership, innovation, and a passion for excellence:

  1. Leadership and Collaboration

    • Led teams of 5+ engineers, mentored mid/senior developers, and collaborated with product managers, designers, and architects to deliver high-impact projects.
    • Bridged gaps between technical and non-technical stakeholders to align vision and execution.
  2. High-Traffic Platforms

    • Built and optimized consumer-facing apps for fintech, retail, and health tech, supporting 10K+ daily transactions and 1M+ users.
    • Focused on performance optimization, modular architecture, and scalability to ensure seamless experiences.
  3. Mobile Security & Performance

    • Implemented OWASP MAS, cryptography, and Play Integrity API to reduce mobile fraud by 95%.
    • Achieved 80% performance improvements and 60% app size reduction through optimizations.
  4. End-to-End Development

    • Managed Google Play and App Store submissions, technical documentation, and automation testing for seamless deployments.
    • Developed apps from scratch, including a retail app with 5 major features (home, product list, authentication, payment).
  5. Innovation & AI Integration

    • Leveraged AI tools (Jetbrains AI, Copilot, Gemini and Ollama) to boost productivity and maintain code quality.
    • Explored Compose Multiplatform to share business logic and UI across iOS and Android.

What I’m Looking For

I’m seeking Android Engineer III, Senior Android Engineer, Lead Android Engineer, Lead Mobile Engineer, Technical Program Manager or Product Engineer roles where I can leverage my decade of expertise to drive impact. Here’s what I bring to the table:

✅ Technical Excellence

  • Kotlin (8+ years), Jetpack Compose (2+ years), MVVM (7+ years), modularization (7+ years), Hilt/Dagger, Koin.
  • Mobile security (OWASP MAS, cryptography, Play Integrity API).

✅ Leadership & Collaboration

  • Proven ability to lead teams, mentor engineers, and thrive in agile/international environments.

✅ High-Impact Projects

  • Experience building high-traffic platforms for fintech, retail, and health tech.

✅ Innovation & Efficiency

  • Passion for AI tools, automation, and modern architectures.

✅ Freelance/Contract Ready

  • Equipped with MacBook Pro M1 Pro (16GB RAM), PC (64GB RAM), and Android/iOS test devices.
  • Open to freelance, contract, or full-time roles (European and Asian time zones).

Why Hire Me?

If you’re looking for a Senior or Lead Android Engineer who can lead teams, optimize performance, and deliver secure, high-quality apps, I’m the right fit. My 10 years of experience, technical expertise, and leadership ensure I can drive impactful results for your projects.

Let’s connect and discuss how I can contribute to your team’s success!

Employment History

Part Time - Mobile Developer at Rey.id Current 2026 - Now
• Solely leading full migration of React Native iOS app to Compose Multiplatform (building on previous 30% Jetpack Compose foundation), targeting 100% native code coverage by Q4 2026 to achieve 30-50% faster UI rendering through native performance optimization • Implementing cross-platform UI components using MVI Clean Architecture to establish consistent design system, reducing platform-specific maintenance efforts by standardizing 15+ core features • Documenting migration patterns for future team adoption, targeting 100% coverage of core features with technical specifications by June 2026 to enable seamless knowledge transfer
Part Time - Mobile Developer at Rey.id 2025 - 2025
• Maintain 5 critical breaking dependencies to ensure compatibility and performance. • Initiate 30% jetpack compose migration from the android legacy code-bases. • Lead feature revamp of ReyCard Digital and app localization • Removed leaking objects on which impact on UI performance rendering • Collaborate with 3 Software Engineer, 2 Product, 2 QA and manage app submission
Lead Frontend Engineer (Mobile & Web) at Rey.id 2025 - 2026
• Lead 5 Engineers (1 full time Compose Multiplatform, 1 part-time React Native and 3 Web) while hands on maintaining the React Native iOS app after the contract ended. • Hands-on the existing android code bases while also involves in building the foundation for the new Compose Multiplatform app using MVI Clean Architecture • Managing Google Play Store and App Store submission ensuring compliance and timely releases. • Leveraged AI Tools (Antigravity, Gemini, Copilot, Jetbrains ACP) to boost productivity by 40% for logical problem-solving, 15% technical decision and 60% for code reviews, while ensuring human oversight for critical decisions. • Collaborated with backend, QA and product teams in an Agile/Scrum environment to align technical and strategic goals, delivering on time and within scope.
Android Engineer at Tech Combine (Omise) 2024 - 2025
Under the contract of Tech Combine, I'm placed on Omise a Thai fintech company, we are working on Philippine client to build *myToyota* wallet app. • Led the development of a fintech app with 10K+ users, optimizing performance for high-traffic scenarios. • Developed 3 InstaPay feature journey integration from QR generation, phone number and bank account • Enhance profile QR image generation to support InstaPay payment • Contribute to proprietary SDK for secure pin verification and adding 2 endpoint support • Improved test code coverage gradually from ~20% to ~50%. • Contribute on VAPT evaluation using 3 mobile app penetration testing, frida, mitm and root detection tools. • Researching on "Open Worldwide Application Security Project (OWASP) MAS (Mobile Application Security)" to comply mobile security standard • Support the automation test using Appium and Robotframework • Technical documentation for the Android InstaPay project. • Collaborate with 3 Mobile Engineer, Product Manager, Designer and Solution Architect
Senior Android Engineer at Quadrant.io (Appen) 2022 - 2024
• App performance improvements by ~80% due to memory leaks on POI submission flow • Reduce ~60% app size by replace OpenCV with TensorFlow lite for blurriness detection • Led the design and implementation of a security solution that reduced mobile fraud by ~95% utilizing AES-128 and AWS Data Key • Implement deferred deeplink for user referral campaign • Provide bearing information by utilizing 3 sensors Accelerometer, Compass and GPS • Integrate Google Play in-app update and manage the flow using Firebase • Contribute to recruitment across 3 domains for mid to lead level Android engineer • Migrated ~70% of legacy code to a modular MVVM Architecture • Adopted Trunk Based Development (TBD), utilizing feature toggles and A/B testing • Architect the analytics adapter for Leanplum and Branch.io • Hands-on with Compose Multiplatform to share iOS and Android business logic • Technical documentation guide for Android onboarding, Code Standard, Architecture and Workflow • Secured 100% of secret keys using Android NDK June 2021 - Aug 2022 Sr. Android Engineer | Healthcare | SehatQ by Sinarm
Lead Android Engineer at Umma 2021 - 2021
• Built 3 podcast journeys with JavaScript interface on the landing screen and native ExoPlayer integration for playback, details and list • Maintain critical media player SDK then bundling it as an AAR • Contribute on app deeplinking across features to support marketing campaign • Contribute 2 domain recruitment process for Senior Android Engineer and QA • Delivered analytics events to support data driven decisions • Re-architected the project to resolve build failures from Software rot • Manage Google Play app submission
Senior Android Engineer at SehatQ 2021 - 2022
• Leading the core Android engineering team • Optimized 2 domain features telemedicine & e-commerce • Contribute to recruitment across 2 domains for mid and senior, collaborating directly with Android Lead • Enhanced architecture in 3 critical areas of unit tests, DI and atomic design • Security improvements due to fraudulent activity by utilizing GCP and NDK • App performance optimizations due to memory leak 2 • Proper implementation on 2 app-link process for deeplinking and universal link • Transform the base UI to atomic design as part of system design • Promote sub-module mechanism for Android system design
Android Engineer (Acting Lead) at PT Matahari Department Store 2018 - 2020
• Developed the MDS Android app from scratch with a team of 2, launching 5 major features (home, product list, details, authentication, payment) • Supported recruitment for mid-level Android engineers • Technical documentation for app-link, analytics attributes and app submission • Migrated ~80% of the app to a modular architecture, with remaining work focused on the payment flow • Manage Google Play app submission
Android Engineer at Mataharimall.com 2017 - 2018
• Enhanced authentication security protocols to resolve logic flaws • Payment integration combined native and javascript interface injection for verification • Developed theater details feature for MatahariMall V2 • Contribute on Junior to Middle Android engineering recruitment process • Integrate analytics, tag manager and moengage for campaign • Migrate 2 feature module Profile and Auth from java to kotlin language
Android Engineer at Alfacart.com 2016 - 2017
The company is merged into Alfa group and under the domain of Alfagift • Developed app from scratch with a team of 3 using java • Implement MVP architecture on 3 module home, detail and profile on post release • Integrate google analytics and tag manager for decision making • Promote dagger dependency injection integration • Utilize Realm database to manage offline behavior

Education

Generative AI for Mobile App Developers at IBM 2025 - 2025
Agile Project Management at Google 2025 - 2025
Ultimate Compose Multiplatform: Android/iOS + Testing at Udemy 2025 - 2025
Software Architecture: Patterns for Developers at LinkedIn 2022 - 2022
Bachelor of Computer Science at Mikroskil University 2010 - 2014