Open to opportunities

Toby Zulkarnain

@tobyzulkarnain

Message

I am a senior full-stack developer specializing in Android and backend fintech systems.

Indonesia

Message

What I'm looking for

I seek senior roles modernizing fintech platforms with a security-first, cloud-native approach, mentoring teams, reducing technical debt, and delivering measurable performance and reliability gains.

I am a strategic technologist and senior full‑stack developer with 7+ years delivering high‑impact, end-to-end fintech and legacy-modernization solutions. I have driven 30%+ transaction speed gains, 70% vulnerability reduction, and 40%+ efficiency improvements while aligning engineering with business OKRs.

My core expertise spans Android (Kotlin/Java), backend (.NET Core, Spring Boot), cloud (GCP, AWS, Azure) and secure payments (NFC, PCI‑DSS, OWASP). I modernize legacy systems using MVVM/Clean Architecture, microservices, CI/CD and observability to reduce technical debt and improve maintainability.

I prioritize pragmatic, security-first engineering and cross-functional collaboration. I am currently pioneering AIM‑Vis for intelligent 3D metadata automation and seek roles where I can modernize financial platforms at scale and mentor engineering teams.

Experience

Work history, roles, and key accomplishments

Current

Software Engineer

Current

PT Bank Mandiri (Persero) Tbk

Nov 2024 - Present (9 months)

Designed and developed core Android modules using Kotlin and Java, modernizing legacy codebases and adopting MVVM/Clean Architecture to improve maintainability. Implemented real-time crash monitoring and performance optimizations to reduce production incidents and improve app startup times.

Kotlin Java MVVM Android Jetpack Firebase Crashlytics Performance Monitoring

Mobile App Developer

PT Entrepreneur Trust Digital

Nov 2023 - Nov 2024 (1 year)

Engineered core features of an enterprise Android app using Kotlin and MVVM, delivering a modular, scalable codebase to improve development efficiency. Resolved production-critical issues via systematic debugging and Firebase Crashlytics, and collaborated on UI/UX redesigns to enhance user experience.

Kotlin MVVM Firebase Crashlytics

Associate Application Developer

PT Mitra Integrasi Informatika

Sep 2022 - Aug 2023 (11 months)

Led full lifecycle development of Android apps, driving Kotlin migrations and implementing MVVM/Clean Architecture to improve maintainability. Integrated RESTful APIs and security features (OAuth2, AES-256) and introduced real-time monitoring to reduce incident resolution time.

Kotlin MVVM Retrofit OAUTH2 Firebase Crashlytics CI CD

Associate IT Project Officer

PT Bank Rakyat Indonesia

Jul 2020 - Aug 2023 (3 years 1 month)

Engineered high-performance Android applications and integrated secure payment solutions (NFC/BRIZZI) using Kotlin and MVVM to support financial transaction workflows. Automated CI/CD pipelines and implemented Firebase monitoring to improve stability and streamline deployments.

Kotlin MVVM Retrofit Jenkins Firebase Crashlytics

Full Stack Developer

PT Nex Solusi Teknologi

Jun 2018 - Oct 2020 (2 years 4 months)

Engineered end-to-end solutions using .NET (C#) and modern JS stacks, migrating monolithic systems to microservices and serverless architectures to improve scalability. Implemented CI/CD with Docker/Kubernetes and optimized database schemas to reduce technical debt and improve performance.

C#ASP.NET Core Docker Kubernetes Azure SQL Server Angular React

Assistant Instructor

Universitas Bina Sarana Informatika

Mar 2018 - Jul 2019 (1 year 4 months)

Developed industry-aligned course materials and supplemental learning resources to increase student preparedness for industry roles. Managed assessments and provided one-on-one mentoring to improve student outcomes and reduce routine inquiries.

Curriculum Development LMS Assessments Mentoring Lesson planning Educational Content

Education

Degrees, certifications, and relevant coursework

STMIK Nusa Mandiri

Bachelor of Computer Science, Information Technology

2015 - 2019

Completed a Bachelor of Computer Science program at STMIK Nusa Mandiri with a focus on information technology and practical software development (2015–2019).

Universitas Bina Sarana Informatika

Associate Degree, Computer Technology

2015 - 2019

Earned an Associate Degree in Computer Technology from Universitas Bina Sarana Informatika, emphasizing applied computing and technical system implementation (2015–2019).

SMK Prestasi Prima

Vocational Diploma, Software Engineering

2013 - 2015

Completed vocational secondary education in Software Engineering at SMK Prestasi Prima, focusing on practical software development and engineering fundamentals (2013–2015).