Karofi 365 (K365)
Senior Flutter / Mobile Engineer · OXII / KAROFI
IoT consumer application serving 50,000+ users through connected water-purifier status, alerts and maintenance experiences.
IoTConsumer
Bùi Hữu Đoàn
Open to senior mobile and technical lead opportunities
Hanoi, Vietnam
Senior Mobile Engineer · Flutter Lead · Mobile Tech Lead
I build mobile products from architecture to release.
Nine years across Flutter, native mobile, IoT, realtime and enterprise products—with hands-on platform architecture, contract design and technical leadership.
MOBILE PRODUCT SYSTEM2017—2026
01
ProductConsumer · Enterprise · Platform
02
EngineeringFlutter · Native · SDK / Contracts
03
DeliveryAPI · CI/CD · Store / Release
9+years engineering
7+years Flutter
50K+K365 users
50+career releases
20person team led
01
Selected work
Commercial mobile systems, shipped and operating.
Three bodies of work across consumer IoT, enterprise operations and multi-product engineering leadership.
OxiiWork
Senior Flutter / Mobile Engineer · OXII Smart Technology
Enterprise workplace platform combining realtime chat, BLE Beacon attendance, approvals, meeting-room and vehicle booking.
EnterpriseRealtime
Hưng Hà Product Ecosystem
Head of Mobile Apps & AI / Mobile Engineering Lead · Hưng Hà Payment JSC
Delivered 30+ applications during the 2017–2022 tenure across logistics, chat, HR, attendance, recruitment and enterprise digitization.
LeadershipEcosystem
View case studyMultiple released products
02
Case studies
Commercial delivery, architecture and production ownership.
OXII / KAROFI · 2023—Present
Karofi 365 (K365)
Own major areas of mobile delivery across architecture, Flutter implementation, native/device integration, APIs, performance, release and maintenance.
Context
K365 is an IoT consumer application in the Karofi ecosystem serving 50,000+ users. It brings connected-device status, alerts and maintenance flows to mobile.
My role
Own major areas of technical delivery: solution design, Flutter implementation, native and API integration, debugging, performance work, release and production maintenance.
Engineering approach
Keep device-facing features behind clear data boundaries, model realtime and cached states explicitly, and isolate platform-specific behavior from product flows.
Outcome
Reliable mobile delivery across connected-device behavior, performance, releases and ongoing production maintenance.
OXII Smart Technology · 2023—Present
OxiiWork
Own major mobile modules across architecture, implementation, cross-platform integration and production delivery.
Context
OxiiWork combines employee communication and operational workflows in one enterprise application, with behavior shaped by different workplace roles.
Technical challenges
Realtime chat state, media and file handling, push, pagination and cache coexist with BLE Beacon attendance, approvals and resource-booking flows.
My role
Led implementation of major modules, designed mobile flows and integrations, reviewed technical approaches, solved cross-platform issues and supported production releases.
Outcome
A cohesive workplace app that carries communication, attendance and business operations without becoming a collection of disconnected utilities.
Hưng Hà Payment JSC · 2017—2022
Hưng Hà Product Ecosystem
Led a team of up to 20 while remaining hands-on across mobile, backend, AI and production operations.
Context
A broad digital-transformation portfolio where mobile products, backend services, AI capabilities and production infrastructure had to move together.
Leadership scope
Set technical direction, created project plans, broke down work and allocated tasks for an application/AI organization of up to 20 people.
Hands-on engineering
Contributed across mobile, backend and AI; supported architecture and production troubleshooting; managed 10+ Linux servers and worked on face recognition and text-to-speech.
Outcome
Released 30+ Android/iOS applications during the 2017–2022 tenure across multiple operational domains.
03
Engineering capabilities
The engineering scope I bring to mobile teams.
Mobile & platform architecture
Clean and modular architecture, host/runtime boundaries, SDK/API contracts, dependency injection and product-grounded state management.
IoT & hardware integration
Connected-device flows, BLE/Beacon, native integration, realtime state and resilient behavior around imperfect networks and devices.
Realtime & chat
WebSocket messaging, conversation state, media/file flows, pagination, local cache, notifications and offline-aware experiences.
Enterprise mobile systems
Attendance, approvals, bookings, field operations and role-aware workflows for daily operational use.
Performance & production
Startup, memory, rendering, large lists, networking, caching, Crashlytics and production troubleshooting.
CI/CD & release
GitHub Actions for Android, Xcode Cloud for iOS, Firebase services and app-store delivery with release ownership.
AI-assisted engineering
Claude Code, Codex, Cursor and Antigravity accelerate implementation, exploration, refactoring and debugging under engineer-owned review.
Technical leadership
Architecture decisions, planning, estimation, task breakdown, code review, mentoring and product/backend/QA coordination.
04
Featured engineering project
Super App Platform
Architected a Flutter super-app platform for sandboxed H5 mini-apps, combining a capability-based native bridge, secure WebView boundaries, signed manifests, generated SDK/contracts and a NestJS backend.
Personal Engineering / Platform Architecture Project2026
Pre-production · Gated integration
A Flutter host for sandboxed H5 mini-apps. The mobile host mediates access to user, payment, device, storage, share and navigation capabilities instead of exposing unrestricted native APIs.
Policy-controlled trust boundaryGenerated Dart / TypeScript contracts
Gate 3: 1,166 / 1,166 tests · 5 workflows greenIntegration maturity verified; production readiness remains gated.
Explore the architecturePLATFORM MAPProduction flags OFF
HOSTFlutter Host
RUNTIMEMini-app Runtime
BRIDGEJS SDK / Contracts
BACKENDNestJS Backend
Flutter · Dart · Melos · OpenAPI · NestJS · Docker
05
Independent client products
Independent mobile delivery across connected devices, social video and cross-border commerce.
Austec Smart Home
Independent Mobile Engineer · Austec Group
Independently delivered a production Flutter application for smart-door and roller-shutter control.
FlutterSmart homeDevice integrationREST API
Short-video Social Platform
Independent Mobile Engineer · Thế Anh 28
Entertainment and social products built around a short-video feed, publishing and community interaction.
FlutterVideo feedMedia uploadNotifications
Taobao / 1688 Commerce
Independent Mobile Engineer · Import business
A cross-border purchasing application for product discovery, cart, ordering and logistics-related workflows.
FlutterBackend APIsOrderingCart
AI-NATIVE ENGINEERING
AI-accelerated. Engineer-owned.
I use modern coding agents to accelerate implementation, codebase exploration, refactoring, debugging and documentation. I remain responsible for architecture, review, integration, security, performance and production quality.
Claude CodeOpenAI CodexCursorAntigravity
06
Experience
Hands-on engineering with increasing ownership.
2023—Present
OXII Smart Technology JSC
Senior Flutter / Mobile Engineer
Technical ownership across K365, OxiiWork and the OXII/Karofi mobile ecosystem: architecture, implementation, native/device integrations, release and production support.
2022—2023
Independent / Client Projects
Freelance Mobile Engineer
Independent product delivery across smart home, social short-video and cross-border commerce applications.
2017—2022
Hưng Hà Payment JSC
Head of Mobile Apps & AI / Mobile Engineering Lead
Led up to 20 people and delivered 30+ apps during this tenure while staying hands-on across mobile, backend, AI and production infrastructure.
2017
NAL
Mobile Developer Intern
Native Android development in Java—the foundation of a career centered on mobile systems.
07
Released product archive
Representative products from 50+ career releases.
A selection from 50+ production mobile apps released across IoT, enterprise, social, logistics, HR and commerce. Public Store links were verified in September 2026.
Karofi 365
Connected water-purifier experience
A
Live listingOXII
Smart-home control ecosystem
A
Live listingAustec Technology
Smart door and roller-shutter control
A
Live listingOxii Work
Workplace operations and collaboration
A
Live listingKarofi Team
Field sales and employee operations
A
Live listingChat365
Realtime workplace messaging
Ai
Live listingStarsClean
On-demand home-service marketplace
Ai
Live listingPCSPOST Customer
Customer shipping workflows
i
Live listingOP PCS POST
Courier and operations workflows
i
Live listingChấm công 365
Face-recognition attendance
A
Live listingNhà Tuyển Dụng 365
Recruiter and hiring workflows
A
Live listingCV Xin Việc 365
Mobile CV creation
A
Live listingPhiên Dịch 365
Voice, image and text translation
A
Live listingStore links verified Sep 2026
08
Resume
Choose the profile that matches the role.
Download the recruiter-ready PDF. A DOCX copy is also available for internal talent systems.
Senior Flutter Engineer
Deep hands-on mobile profile
Mobile Tech Lead
Leadership + hands-on engineering
About
Bùi Hữu Đoàn
Based in Hanoi, I specialize in Flutter and mobile platform engineering across commercial products, native integrations, explicit contracts and security-conscious system boundaries.
Hanoi, Vietnam
B.Sc. Information Technology · Thuy Loi University · 2013—2018
Vietnamese · Native | English · Intermediate