01 / 03Mobile App2026
Competence
Every focused minute builds a town, piece by piece.
- Released Oct 2026
- iOS + Android
- 8 languages
Available for select projects
Engineer forthe whole system.
Mobile apps, cloud backends, internal systems — and the strategy that ships them.
About
01AboutEngineer · Architect · PM
I build the whole product — the app in your hand, the AI behind it, the cloud underneath, and the plan that gets it shipped. Ten years of turning loose ideas into software people actually use.
- Years shipping, from first sketch to production
- 10+
- Years shipping, from first sketch to production
- Experience
- Saved per year through RFP and vendor strategy
- $70k
- Saved per year through RFP and vendor strategy
- Corporate Site Redesign
02AppsApps designed & built
A few screens from apps I've designed and built, end to end.
02 / 03Mobile App2026
Indian Calculations
Mental-math training, turned into a daily habit.
- Released Apr 2026
- App Store
03 / 03Mobile App2025 — Live
Chaletta
A Korean learning app, from first word to TOPIK.
- iOS + Android
03Selected Work10 projects · 2017 — 2026
Things shipped.
Apps on the store, services in eighty stores, and the plans that made the budget work.
04CapabilitiesEnd to end
Mobile
Native-feeling apps that people open every day.
- Flutter / Dart
- iOS & Android release
- Habit & learning UX
- Subscription design
Used in — CompetenceIndian CalculationsChaletta
AI Systems
LLMs wired into real workflows, not demos.
- LLM integration
- RAG pipelines
- Vector search & embeddings
- OpenAI / Claude APIs
Web & Cloud
Serverless backends that cost cents, not thousands.
- TypeScript / React / Next.js
- PHP / Laravel · Node.js
- AWS Lambda · DynamoDB · Amplify
- Vercel · Neon
- MySQL · PostgreSQL · SQL Server
Used in — Calendar ReportAR Photo ServiceConstruction Site Cloud
Strategy
The part before the code — and the part after.
- DX strategy & planning
- RFP & vendor negotiation
- Requirements definition
- KPI design & team leadership
Used in — Corporate Site RedesignOMO Project
05Experience2015 — Now
2024 — Now
PM / Tokyo Lead
Contract Development / SES Company
- Managing and driving projects as PM
- Overseeing organizational management of the Tokyo branch
DetailsLess
At a company operating contract development and SES services, serving as PM for project management and execution while overseeing Tokyo branch operations.
2022 — 2024
DX Strategy PM
Major Retail Chain
- Led planning, RFP preparation, and vendor selection for a corporate site redesign, achieving approximately $70,000 in annual cost savings
- Planned, researched, and prototyped the corporate app for the OMO project; designed the in-store pickup concept and coordinated across departments to finalize strategy
DetailsLess
End-to-end ownership from employee interviews and planning proposals to requirements definition, development, and operations. Led the launch of in-house services from scratch and upstream processes for a corporate site redesign.
- Built and operated the AR Photo Service from scratch — deployed in 80+ stores, reaching 30,000+ users and 100,000+ photo sessions
- Reduced monthly server costs to just a few dollars by adopting serverless architecture
- AR Photo Service was also adopted in a government ministry collaboration project
React · TypeScript · Node.js · AWS Amplify · Lambda · DynamoDB · API Gateway · Cognito · S3
2020 — 2022
IT Systems / DX Initiative Launch
Major Retail Chain
- Delivered high-quality feature additions to core systems through thorough impact analysis and testing
- Automated pop-up store sales aggregation and publisher revenue reporting, reducing workload by 48 hours/month
DetailsLess
Worked in the IT Planning Department on core system development, account management, and POS terminal setup. Contributed to launching the DX department through proactive process improvement proposals and new business initiatives.
- Proposed and implemented the adoption of an internal groupware solution
- Built an internal employee blog site and evaluated/verified BI tools
Unicage · Shell Script · PHP · WordPress · JavaScript · Red Hat
2017 — 2020
Contract Developer / Part‑time Lecturer
SES Company
- Handled architecture, detailed design, and development for a construction site cloud management system; proactively created and submitted the API architecture beyond assigned scope
- Worked on equipment inventory system overhaul while stationed at a major electronics manufacturer
DetailsLess
After being stationed at a major electronics manufacturer through SES, worked on contract development of a cloud management system for the construction industry. Simultaneously served as a part-time lecturer at alma mater vocational school.
- Served as a part-time C language lecturer for first-year students at alma mater, teaching twice a week — invited directly based on academic track record and reputation
Laravel · PHP · C# · .NET · MySQL · SQL Server · Amazon Linux · C
2015 — 2017
Web Engineer
System Integrator
- Handled diverse contract projects including estate planning services, telephony services, content management systems, and social media campaign systems
DetailsLess
Gained experience across the full development lifecycle — from requirements definition to design, implementation, testing, and release — working on web services and e-commerce systems as a system integrator. Acquired a broad tech stack through diverse client projects across multiple industries.
Ruby on Rails · PHP · CakePHP · Java · Spring Boot · JavaScript · AngularJS · PostgreSQL · MySQL
06ContactNew projects · Collaborations
Write directly
kuroumaru@zokko.devMobile apps, AI integration, or a plan that needs an engineer in the room — tell me what you're making.