Android Software Engineer  ·  Tokyo, Japan

Yosuke

Sakurai.

Production Android with a focus on stability, performance, and root-cause analysis.

ExperienceContact
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01

About

Android engineer with 6+ years building and supporting production Android apps, with emphasis on stability, performance, and runtime behavior.

Experienced diagnosing production issues—crashes, ANRs, and device-specific failures—using logs, stack traces, and systematic root-cause analysis.

Comfortable across the Android stack: lifecycle, threading, memory, MVVM, Redux/MVI, multi-module codebases, and Dagger/Hilt in high-availability environments.

Japanese (native) · English (fluent)

02

Experience

Rakuten

Mar 2024 – Present

Android Developer

Tokyo

  • Features and maintenance in a large-scale e-commerce Android app with strong uptime expectations.
  • Redux/MVI with MVVM for predictable UI and state across configuration changes and lifecycle.
  • Multi-module structure and Dagger/Hilt for lifecycle-aware components and reduced coupling.
  • Performance work: main-thread blocking, background execution, and safer network retry flows.
  • Quality: JUnit/Mockito, SonarQube remediation, Bitrise CI/CD, and AI-assisted code review in PR workflow.
  • Internal tooling integrating Confluence, Jira, GitHub review, and Figma; workflow automation with Claude Code MCP.

U.S. Bank

Oct 2020 – Jan 2024

Android Developer

Minneapolis

  • Epic delivery, testing, and coordination with offshore teams.
  • Multi-module apps with Dagger; collaboration across product, UX, and engineering.
  • Banking features, performance, and stability for customer-facing mobile banking.

JetBlue Airways

Jul 2019 – Sep 2021

Android Developer (Internship)

Chicago, IL

  • MVVM at project level; Kotlin modules for reservation and waitlist.
  • Retrofit/RxJava integrations; Google Vision + Room for QR and flight data.

Shoe Carnival

Mar 2018 – Jun 2019

Android Developer (Internship)

United States

  • Material Design UIs; Volley + RecyclerView; Dagger 2 and MVP.

Sotheby's International Realty

Apr 2017 – Feb 2018

Android Developer (Internship)

United States

  • Property detail flows; Volley/Picasso; FCM alerts; MPChart visualizations.

Instin LLC

Jun 2016 – Mar 2017

Android Developer (Internship)

United States

  • Orientation and screen-density support; custom calendar for school activities; Material Design patterns.
03

Skills

Languages

Java, KotlinJavaScript, TypeScriptPython (beginner)

Android & platform

Activity / Fragment / Service lifecycleThreading: coroutines, executors, background workersMemory, leaks, ANRs, crashes, OS/version differences

Architecture & delivery

MVVM, Redux/MVIMulti-module apps, Dagger 2 / HiltGradle, Bitrise CI/CD, GitJUnit, Mockito, SonarQube
04

Projects

LoA— Law of Attraction

Mindful app usage: pause before distracting apps with intention, gratitude, and affirmations.

Website
  • Android app uses AccessibilityService to detect launches of apps you choose, then shows a mindfulness / LoA screen before entry—without reading other apps' content.
  • Customizable intercepts, cooldowns, affirmations, and progress toward more intentional phone use.
  • Web stack: Next.js, Firebase (Auth, Firestore, Storage), Shotstack video tooling, Anthropic SDK, and related automation.
AndroidNext.jsFirebaseShotstackAnthropic API

TaskGate— Digital wellness

Break impulsive opens: complete a micro-task before accessing blocked apps.

WebsiteApp StoreGoogle Play
  • Flutter app for iOS & Android: block distracting apps, intercept opens, and offer breathing, affirmations, quizzes, or partner-linked tasks.
  • Native SDKs (Swift, Kotlin) and Flutter package for partner integrations; Firebase Cloud Functions where used.
  • Marketing site: Next.js landing, waitlist/contact via Firestore.
FlutterSwiftKotlinFirebasePartner SDKs

Deckbase— AI flashcards

Learn with decks, FSRS spaced repetition, rich templates, and AI-assisted card creation.

WebsiteApp StoreGoogle Play
  • Flutter app: Anki-style study (Again/Hard/Good/Easy), FSRS scheduler, templates with text/image/audio/quiz blocks, OCR and voice input, Anki .apkg and spreadsheet import.
  • Offline-first Drift/SQLite with Firebase sync (Auth, Firestore, Storage), RevenueCat, FCM, home widgets.
  • Web companion: Next.js marketing site, SEO/ASO workflows, Cloud Functions, optional MCP server for tooling.
FlutterRiverpodDriftFirebaseRevenueCatNext.js

EverJournal— AI journaling

AI-powered storytelling for your life — reflect and remember what matters.

Website
  • Mobile app (Flutter, iOS & Android) for private journaling with AI-assisted reflection and storytelling.
  • Firebase backend (Auth, Firestore, Functions, Storage) with real-time sync and Cloud Functions for AI processing.
  • Companion web app (Next.js) for marketing, web access, and deep-link routing.
FlutterFirebaseNext.jsCloud Functions

AgentOS— AI agent management

Observe, organize, and control AI agents across tools — Claude Code, Cursor, and more.

  • Local-first platform providing hierarchical structure for AI agent sessions: projects, teams, and CHARTER.md-driven context inheritance.
  • Cross-tool observability: detect and track agents regardless of which tool runs them; HMAC-secured bridge and approval workflows.
  • TypeScript backend with Supabase, APNs/FCM push, and mobile pairing API.
TypeScriptSupabaseExpressAPNsFCM
05

Education

University of Central Oklahoma, Edmond

Computer Science

May 2016 – Dec 2019

06

Contact

Let's talk.

Open to conversations about Android engineering roles and technical collaboration.