Данило

DANIEL HAPOTIN
FLUTTER FULL-STACK DEVELOPER
Lviv, Ukraine • [відкрити контакти](див. вище в блоці «контактна інформація») • [відкрити контакти](див. вище в блоці «контактна інформація»)

SUMMARY
Flutter Full-Stack Developer with 4+ years of experience building scalable, high-load, production-
grade mobile applications for iOS and Android. Strong expertise in Flutter, Dart, Firebase, REST API
integration, and scalable application architecture. Experienced in full-cycle development: from
designing architecture and implementing core functionality to optimization, release management,
and production support.
Focused on performance optimization, clean architecture, and maintainable code. Skilled in solving
complex production issues, improving application stability, and delivering smooth user experiences
for real-world products with thousands of active users.

WORK EXPERIENCE
Subscription Platform / Flutter Full-Stack Developer February 2026 – Present
Telegram-based subscription platform similar to Tribute with creator monetization tools.
Features
Subscription system
Telegram authorization
Payment integration
Media content management
Push notifications
Admin dashboard
Technologies
Flutter, Dart, Firebase, REST API, BLoC, Clean Architecture, Cloud Functions
Responsibilities
Built project architecture from scratch
Implemented authentication and payment flows
Developed scalable state management structure
Integrated Firebase backend services
Optimized app performance and caching

Mobile Arcade Game / Flutter Full-Stack Developer October 2025 – December 2025
Hyper-casual mobile game focused on physics-based ball mechanics, smooth gameplay, and high
FPS stability across Android and iOS devices.
Technologies
Flutter, Dart, Firebase, Hive, Google Mobile Ads (AdMob), Figma
Responsibilities
Developed physics-based gameplay mechanics and ball movement system.
Optimized rendering performance and FPS stability for low-end devices.
Integrated Firebase (Analytics, Crashlytics, Remote Config).
Implemented local game state persistence using Hive.
Added AdMob monetization: rewarded, interstitial, and banner ads.
Built responsive UI from Figma designs.
Reduced frame drops, memory leaks, and animation-related performance issues.
Implemented async asset loading and gameplay optimizations.
 UPC — E-commerce Web Platform / Flutter Full-Stack Developer June 2025 – October 2025
Stack: Flutter Web, Firebase (Auth, Firestore, Storage, Cloud Functions), Google Ads, Firebase
Hosting
Developed a full-stack e-commerce web platform with a custom admin dashboard for managing
products and business operations.
Built a complete e-commerce system (catalog, product pages, cart, orders) using Flutter Web
Developed a Firebase-powered admin panel for managing products, pricing, and inventory in
real time
Implemented real-time data synchronization between client storefront and admin dashboard
Integrated Google Ads for monetization and traffic tracking
Designed a responsive UI optimized for desktop and mobile web usage
Structured and optimized Firestore data model for scalability and performance

Global Law Consulting — Corporate Web Platform / Flutter Full-Stack Developer April 2025 – June 2025
Stack: Flutter Web, Firebase Hosting, Firestore, Custom Domain
Developed a corporate website for a legal consulting company with dynamic content management
and custom domain deployment.
Built a responsive corporate website using Flutter Web
Configured Firebase Hosting with custom domain setup and deployment pipeline
Implemented admin panel for managing website content (services, articles, company info)
Created contact forms with submissions stored and managed in Firestore
Optimized performance and SEO structure for web visibility and fast loading
Ensured full responsiveness across all devices (desktop, tablet, mobile)

E-commerce / Flutter Full-Stack Developer September 2024 – March 2025
Developed and maintained a high-performance cross-platform retail application with a multi-tier
product catalog.
Engineered a secure checkout pipeline by integrating Stripe SDK, supporting multi-currency
payments and automated coupon validation.
Designed complex Firestore data models with optimized indexing to handle deep product
categories, search filters, and user order history.
Implemented advanced state management strategies for real-time cart synchronization,
handling offline states, and dynamic pricing updates.
Accelerated screen rendering times by 35% through custom image caching algorithms and
lazy-loading heavy UI layouts.
Banking App / Flutter Developer November 2022 – August 2024
Built from scratch and maintained production-grade cross-platform mobile applications (iOS,
Android) using Flutter, along with a supporting web platform developed in React.
Implemented clean architecture for maintainability.
Resolved deployment issues and successfully published applications to the App Store and
Google Play.
Implemented lazy loading, pagination, and infinite scrolling for large datasets.
Handled crash analytics & monitoring (Firebase Crashlytics).
Reduced crash rate from 97.3% to 99.4% crash-free sessions by fixing async state issues and
memory leaks on production.

Weather App / Flutter Developer June 2022 – September 2022
Built pixel-perfect UI based on Figma designs with full responsiveness across devices.
Reduced app startup time and memory usage via performance tuning.
Implemented Model-View-Presenter architecture for scalability, reducing app maintenance cost
for the client.
Created custom reusable widgets library, reducing development time by 50%.
Implemented custom animations & transitions for improved UX.
Handled dark mode & theming system with dynamic styling support.
 PROJECTS
Built scalable, production-grade cross-platform mobile and web applications from scratch using Clean
Architecture and BLoC/MVP patterns.
Structured robust offline-first repository layers using Hive and handled secure data storage.
Integrated complex REST APIs via Dio/Retrofit with custom interceptors for token management and
global error handling.
Developed and optimized backend logic utilizing Firebase Cloud Functions to handle server-side
operations and business logic.
Designed scalable, real-time data synchronization pipelines between client applications and admin
dashboards using Firestore.
Configured automated push notifications using Firebase Cloud Messaging (FCM) and set up secure
authentication flows.
Significantly improved application stability, raising the crash-free sessions rate from 97.3% to 99.4% by
refactoring asynchronous state handling and fixing memory leaks.
Optimized rendering performance, UI transitions, and asset loading to achieve stable, high-FPS
gameplay and smooth responsiveness on low-end devices.
Accelerated data rendering for large datasets by implementing lazy loading, cursor-based pagination,
and infinite scrolling.
Implemented secure checkout pipelines and payment gateway integrations for creator monetization and
e-commerce systems.
Integrated multi-format ad monetization (rewarded, interstitial, and banner ads) using Google Mobile
Ads (AdMob).
Managed the full deployment pipeline, successfully publishing and supporting applications on the App
Store and Google Play Console.

TECHNOLOGIES
Mobile Development Backend & APIs Local Storage
Flutter REST API Hive
Dart Dio SharedPreferences
State Management Retrofit Secure Storage
BLoC / Cubit Firebase Tools & Platforms
Provider Cloud Functions Git
GetX WebSockets GitHub
Redux Firebase App Store Connect
RxDart Authentication Google Play Console
Architecture Firestore Figma
Clean Architecture Cloud Messaging VS Code
MVP Crashlytics Additional
Repository Pattern Analytics Responsive UI
Dynamic Links Performance Optimization
Push Notifications
Deep Links
Async Programming

EDUCATION
Bachelor in computer sciences
V.N. Karazin Kharkiv National University
Graduated: July, 2024

LANGUAGES
Ukrainian - native
Russian - native
English — B1+ / B2 Reading Technical Documentation