Hrvoje is available for hire
Hire HrvojeHrvoje Čukman
Verified Expert in Engineering
Software Developer
Zagreb, Croatia
Toptal member since November 24, 2022
Bio
Hrvoje is an experienced and passionate Flutter developer with extensive experience creating mobile applications. He has delivered mobile apps ranging from MVPs to million-user apps. Hrvoje has further experience in education, vehicle sharing, retail, and fintech. As a co-founder and lead mobile developer of a vehicle-sharing startup, he has developed architecture and project planning software and led a mobile team.
Portfolio
Bashar Hamad
GitHub, Artificial Intelligence (AI), React Native...
Spectora, Inc
Flutter, Riverpod, Model View ViewModel (MVVM), Large Language Models (LLMs)...
Abdullah Al-Shaya
Flutter, Dart, DevOps, NestJS, Full-stack, Mobile Apps, Software Architecture...
Experience
- Flutter - 7 years
- Dart - 7 years
- Android Studio - 7 years
- Cloud Firestore - 6 years
- Firebase - 6 years
- REST - 5 years
- Agile Deployment - 4 years
- Swift - 2 years
Preferred Environment
Flutter, Dart, Slack, Mobile Development, Firebase, Cloud Firestore
The most amazing...
...project I've developed is a Roll+ app, a platform currently with over 100,000 rides where people can rent electric vehicles.
Work Experience
Senior Architect, Developer, and Project Manager
2025 - 2026
Bashar Hamad
- Designed and implemented a full MVP architecture using NestJS and Flutter, enabling end-to-end invoice capture, OCR processing, review, and archival within a 4-week delivery timeline.
- Integrated Google Document AI OCR pipelines to extract structured invoice data (supplier, totals, dates) with per-field confidence scores, supporting human-in-the-loop correction and AI improvement tracking.
- Provisioned and deployed a production-ready cloud infrastructure on Google Cloud (Cloud Run, Cloud SQL, Storage, IAM), including staging and production environments with CI/CD automation.
- Delivered a complete invoice lifecycle flow from camera/gallery capture to OCR review, edit, archive, and search, supporting multilingual UI (English/Arabic) across mobile and web clients.
- Implemented a multi-tenant–ready database schema with audit logging, encryption-at-rest foundations, and event-driven design placeholders to support future ERP and third-party integrations.
Technologies: GitHub, Artificial Intelligence (AI), React Native, Optical Character Recognition (OCR), Full-stack, MySQL, Software Architecture, Flutter, Payment Processing, Web Development, Computer Vision, Google Maps API
Senior Flutter Developer
2025 - 2025
Spectora, Inc
- Implemented a new AI module inside an existing Flutter mobile application, extending the current architecture while maintaining clean principles and MVVM patterns.
- Built secure image, video, and audio upload pipelines from the mobile app to back-end AI services, including real-time progress tracking and state synchronization using Flutter state management.
- Delivered AI-processed home inspection results to the UI by consuming back-end evaluation outputs, transforming raw AI responses into structured, user-friendly inspection insights within the app.
Technologies: Flutter, Riverpod, Model View ViewModel (MVVM), Large Language Models (LLMs), BloC, Swift, Kotlin, Audio Processing, Image Processing, Firebase, Speech-to-Text (STT), Computer Vision
Flutter Developer
2025 - 2025
Abdullah Al-Shaya
- Developed a full-featured Flutter mobile application from scratch using clean architecture principles and Riverpod for scalable and maintainable state management.
- Integrated Google Maps into the mobile app to display real estate listings with geolocation support and dynamic property markers.
- Built and deployed a NestJS back end with modular architecture, incorporating role-based authentication, OTP-based sign-in, and secure session handling.
- Collaborated closely with designers and stakeholders to align UI/UX implementation with Figma prototypes, ensuring a pixel-perfect and responsive design.
- Reviewed and optimized legacy code, improving performance and maintainability across multiple modules of the application.
- Implemented secure RESTful API endpoints with data validation and error handling, enabling seamless integration between mobile and back-end services.
Technologies: Flutter, Dart, DevOps, NestJS, Full-stack, Mobile Apps, Software Architecture, Twilio, Agile, API Design, Architecture, SQL, Payment Processing, Web Development, Google Maps API
Flutter Developer
2024 - 2025
Queue LLC
- Developed the Flutter app for iOS and Android, enabling real-time interaction between users and DJs through features such as song requests, video requests, and shoutout requests.
- Designed and implemented a wallet top-up system, allowing users to manage in-app transactions effectively.
- Developed PixiJS web application, a responsive online casino platform enabling players to access games, manage accounts, and perform transactions seamlessly.
- Led the development of the admin dashboard in React, enabling efficient management of user accounts, transactions, and game settings.
- Collaborated with cross-functional teams, including designers and backend developers, to deliver high-quality features on schedule.
- Implemented a robust authentication system, including OTP-based login and forgot PIN recovery workflows, ensuring secure access for players.
- Connected multiple game providers’ APIs, enabling players to interact with a diverse selection of games while ensuring smooth gameplay.
- Used Laravel (PHP) to implement back-end features, such as refining API endpoints, enhancing database queries, and integrating 3rd-party services.
Technologies: Flutter, Dart, REST APIs, PHP, React, TypeScript, PixiJS, Vite, Capacitor, Stripe, Riverpod, Amazon S3 (AWS S3), PostgreSQL, Full-stack, Stripe API, Mobile Apps, Software Architecture, Twilio, Agile, Architecture, SQL, Payment Processing, identity verification, Web Development, Vercel, Google Maps API
Technical Lead (via Toptal)
2024 - 2024
Cherry LLC
- Reviewed and enhanced the Flutter mobile app, implementing significant code improvements to boost performance and reliability.
- Analyzed and upgraded a React web application, making code refinements and fixing bugs to enhance functionality and user experience.
- Evaluated and optimized back-end code using Node.js and MongoDB, implementing code improvements and bug fixes to increase system stability and performance.
Technologies: Technical Leadership, Mobile, React, Node.js, Flutter, JavaScript, MongoDB, REST APIs, Stripe, Riverpod, Full-stack, Stripe API, Mobile Apps, Software Architecture, Twilio, Agile, API Design, Architecture, Payment Processing, Web Development, Google Maps API
Flutter Developer
2024 - 2024
Harlowe Health LLC
- Developed a Flutter Twilio messaging package that encapsulates both iOS and Android SDKs, incorporating robust chat functionality into the application.
- Refactored legacy code to align with modern best practices, segregating presentation, domain, and data layers to optimize maintainability and scalability.
- Implemented REST API request logic using Dio and Retrofit packages, enhancing data integration and network communication within the app.
- Added Flavors support for production and development builds, enabling customized configurations and simplifying management across different environments.
- Implemented the Codemagic CI/CD platform to streamline development workflows and enhance deployment efficiency for multiple app versions.
- Integrated Firebase messaging for notifications support, significantly improving user engagement and communication within the app.
- Created an admin web application from scratch using Angular, designed to enhance administrative capabilities and streamline back-end management processes.
- Implemented authentication in the Angular project using Azure B2C, ensuring secure access and identity management for administrative users.
Technologies: Flutter, Angular, .NET, REST APIs, Azure, Riverpod, Mobile Apps, Software Architecture, Twilio, Agile, SQL, Web Development
Flutter/Firebase Developer (via Toptal)
2024 - 2024
BoBo App, Inc
- Implemented key features for a social networking app, such as QR code group joining, push notification reminders, and sign-in integrations with Google and Apple.
- Developed a user-friendly profile picture upload function and a task creation screen with customizable frequency settings (daily, weekly, monthly) following Figma designs.
- Enhanced the user experience by integrating roommate statistics on the Roomies screen and establishing Firebase production/testing environments.
Technologies: Flutter, Dart, Firebase, iOS, Android, Riverpod, Mobile Apps, Software Architecture, Agile, Firebase Cloud Functions
Lead Software Engineer
2023 - 2024
Ani Biome
- Led the launch of Ani Biome on the App Store and Google Play, receiving user acclaim for its intuitive interface and precise gut health diagnostics.
- Integrated TensorFlow Lite ML models, enhancing real-time diagnostic capabilities and significantly improving user experience.
- Developed and managed a scalable, high-performance back end using Google Cloud and Node.js, ensuring efficient data handling and system communication.
- Implemented an OpenAI API, adding advanced AI features like natural language processing and elevating the app's personalized user interaction capabilities.
Technologies: Dart, Flutter, Android Studio, JavaScript, Node.js, Firebase, Cloud Firestore, Firebase Realtime Database, Crashlytics, Google Cloud, Google Analytics, OpenAI, ChatGPT, APIs, REST, GraphQL, TensorFlow, Machine Learning, App Store, Google Play Store, CI/CD Pipelines, Data Science, Firebase Cloud Messaging (FCM), Mobile, Technical Leadership, REST APIs, Android, iOS, Android SDK, Agile Software Development, Stripe, Riverpod, Stripe API, Mobile Apps, Software Architecture, Agile, API Design, Firebase Cloud Functions
Co-founder | Lead Flutter Developer
2021 - 2024
Roll+
- Released the Roll+ app, a platform where other people can rent their vehicles. The app was published in 2022 and, in its first three months of production, had over 10,000 scooter rides.
- Designed the project database in Firebase/Cloud Firestore.
- Created tasks in Jira and ensured the project was delivered on time.
- Developed a CI/CD for the Android and iOS app with Codemagic.
Technologies: Flutter, Firebase, Cloud Firestore, Dart, Firebase Hosting, TypeScript, Google Cloud, Codemagic, GitHub, Mobile Apps, Scrum, JavaScript, Node.js, Full-stack, API Integration, Mobile Development, Minimum Viable Product (MVP), NoSQL, Firebase Cloud Messaging (FCM), Mobile, Technical Leadership, REST APIs, Android SDK, Angular, Bluetooth, Software Architecture, Agile, API Design, Payment Processing, Firebase Cloud Functions, Google Maps API
Senior Flutter Developer
2021 - 2023
Q Agency
- Developed an application to collect football players' digital cards for the FIFA World Cup 2022 Qatar. Users can scan physical cards from the REWE supermarket and organize them digitally.
- Managed the development of a mobile app for pet tracking for Deine Tierwelt, Germany's leading pet community.
- Worked on the fintech app for one of Switzerland's largest retail and wholesale companies. The app offers digital banking services, including pension funds, investments, and insurance.
- Collaborated with a team of up to five Flutter developers, project managers, business analysts, and QA from the Q Agency side and a couple of back-end developers, project managers, business analysts, and QA from the client side.
Technologies: Flutter, REST, SignalR, GraphQL, Android Studio, Swift, Kotlin, Agile Deployment, Dart, Firebase, Android, iOS, Mobile Apps, Scrum, Jira, Full-stack, API Integration, Mobile Development, Minimum Viable Product (MVP), NoSQL, Firebase Cloud Messaging (FCM), Mobile, Technical Leadership, REST APIs, Amazon Web Services (AWS), Crypto, Android SDK, Riverpod, BloC, Software Architecture, Agile, Google Maps API
Co-founder and Lead Flutter Developer
2019 - 2021
Self-employed
- Developed and released the Rolla - Roll & See app, a scooter renting app for our custom-made scooters.
- Designed the project database in Firebase Firestore.
- Organized tasks in Jira and ensured that the project was delivered on time.
- Created CI/CD for the Android and iOS app with GitHub Actions and Fastlane.
- Worked on the back end of the project with Google Cloud.
Technologies: Flutter, Firebase, Cloud Firestore, Dart, Firebase Hosting, TypeScript, Google Cloud, Fastlane, GitHub, Agile Software Development, Jira, Mobile Apps, Payment APIs, PayPal API, JavaScript, Node.js, Full-stack, API Integration, Mobile Development, Minimum Viable Product (MVP), NoSQL, Firebase Cloud Messaging (FCM), Mobile, Technical Leadership, Android SDK, Agile
Flutter Developer
2019 - 2020
Kickstage
- Developed an e-learning app for a client from Germany in Flutter.
- Worked in a team of three developers and UI/UX designers.
- Implemented bloc state management in the Flutter app.
Technologies: Flutter, Dart, Android Studio, Mobile Development, NoSQL, Mobile, Android SDK, Mobile Apps, Agile
Flutter Developer
2018 - 2019
Romana Beach Resort
- Developed a smart cash register app in Flutter for Linux and Windows.
- Created a mobile app for employees to receive new retail items, restock shelves and count the inventory.
- Connected software to the smart shelf can change retail item prices dynamically.
Technologies: Flutter, Dart, Desktop, REST, GitHub, Fastlane, Mobile Development, Mobile, Android SDK, Agile
Experience
Roll+ App for iOS and Android
A Flutter-based app where we provide renters the platform to rent their vehicles through our app and see all kinds of statistics about their cars, rides, and income. The app was published in 2022 and, in its first three months of production, had over 10,000 scooter rides. I was in charge of the solution architectures of the project, leading the mobile team and app development. Also, I was working together with the back-end team to connect the app with the back-end. The app communicates with Firebase and has a lot of its features. Some of them are:
◦ Authentication of Phone, Apple, and Google sign-in.
◦ Firebase Cloud Function, written in TypeScript.
◦ Crashlytics
◦ Cloud Messaging
◦ Dynamic Links
◦ Braintree for Pay, Apple Pay, Google Pay, and Credit Cards.
◦ Authentication of Phone, Apple, and Google sign-in.
◦ Firebase Cloud Function, written in TypeScript.
◦ Crashlytics
◦ Cloud Messaging
◦ Dynamic Links
◦ Braintree for Pay, Apple Pay, Google Pay, and Credit Cards.
Rolla | Roll & See App for iOS and Android
Rolla, the Roll & See app is built in Flutter and published on the App Store and Google Play. It is a scooter renting app for custom-made scooters and was released in 2021. I was in charge of the solution architectures of the project, leading the mobile team and app development. Also, I was working on implementing some back-end features. The back-end is done with the Google Cloud and Firebase Cloud functions and is written in TypeScript. The app communicates with Firebase and has the following features:
◦ Authentication of the Phone, Apple, and Google sign-in.
◦ Storing images and app logs to Firebase storage for further usage.
◦ Hosting admin web app with Firebase hosting.
◦ Firebase function is written in TypeScript.
◦ Crashlytics
◦ Cloud messaging sending notifications to users.
◦ Dynamic links.
◦ Sending in-app money.
◦ Referrals.
◦ Apple Pay, Google Pay, PayPal, Credit Cards.
◦ Authentication of the Phone, Apple, and Google sign-in.
◦ Storing images and app logs to Firebase storage for further usage.
◦ Hosting admin web app with Firebase hosting.
◦ Firebase function is written in TypeScript.
◦ Crashlytics
◦ Cloud messaging sending notifications to users.
◦ Dynamic links.
◦ Sending in-app money.
◦ Referrals.
◦ Apple Pay, Google Pay, PayPal, Credit Cards.
Digital Cards Album App
The number one sports app in Germany, 2022. With the app, users can collect digital cards of football players for the FIFA World Cup 2022 Qatar. Users can scan physical cards from the REWE supermarket and organize them digitally.
Digital Banking App
Fintech app for one of Switzerland's largest retail and wholesale companies. The app offers digital banking services, including pension funds, investments, and insurance.
Animal Market Mobile App
Mobile app for Germany's first animal market with online identification procedures. The app is made for Deine Tierwelt, Germany's leading pet community, and allows users to track their pet's behavior, buy insurance and pet products.
Flutter/OpenAI API Package
https://pub.dev/packages/chat_gpt_flutterThis Flutter package enables easy integration with OpenAI's ChatGPT and APIs, streamlining AI feature implementation in Flutter apps. It simplifies API connections, request management, and response handling, offering developers a user-friendly interface for adding AI capabilities.
ChatGPT-based Flutter App for Automating Company Tasks
This ChatGPT-based Flutter app for automating company tasks is a cutting-edge application designed to revolutionize task management within businesses. Utilizing the capabilities of OpenAI's ChatGPT, this app automates various routine tasks, from scheduling meetings to managing emails. Built using Flutter, it offers a seamless and responsive user experience across multiple platforms. Its intuitive interface and AI-driven functionality make it an ideal solution for companies looking to enhance efficiency and productivity through automation.
Education
2017 - 2021
Bachelor's Degree in Software Engineering and Information Systems
University of Zagreb, Faculty of Electrical Engineering and Computing - Croatia, Zagreb
Certifications
MAY 2021 - PRESENT
Structuring Machine Learning Projects
DeepLearning.AI
FEBRUARY 2021 - PRESENT
Google's Go Programming Language
Udemy
FEBRUARY 2021 - PRESENT
Neural Networks and Deep Learning
DeepLearning.AI
FEBRUARY 2021 - PRESENT
Machine Learning
Stanford Online
Skills
Libraries/APIs
Node.js, REST APIs, React, Stripe, Stripe API, Google Maps API, SignalR, PayPal API, TensorFlow
Tools
Android Studio, GitHub, Jira, Firebase Cloud Messaging (FCM), Codemagic, Fastlane, ChatGPT, Capacitor, Crashlytics, Braintree SDK, Slack, TestFlight, Xcode, Google Analytics
Languages
Dart, TypeScript, JavaScript, SQL, GraphQL, Swift, Kotlin, Python, Java, Go, C, PHP
Frameworks
Flutter, Riverpod, NestJS, Android SDK, Angular, OAuth 2, .NET, PixiJS, React Native
Paradigms
REST, Agile Software Development, Object-oriented Programming (OOP), Mobile Development, Agile, Scrum, DevOps, Model View ViewModel (MVVM)
Platforms
Firebase, Mobile, Twilio, Android, iOS, Amazon Web Services (AWS), Blockchain, Vercel, Bitrise, Azure, Desktop
Storage
Cloud Firestore, NoSQL, Google Cloud, Firebase Realtime Database, Amazon S3 (AWS S3), PostgreSQL, MongoDB, MySQL
Other
Agile Deployment, IT Projects, Mobile App Development, Mobile Apps, Full-stack, Minimum Viable Product (MVP), App Store, Google Play Store, BloC, Software Architecture, Architecture, Artificial Intelligence (AI), Payment Processing, identity verification, Web Development, Firebase Cloud Functions, Computer Vision, Firebase Hosting, API Integration, OpenAI, APIs, Technical Leadership, Crypto, Bluetooth, API Design, Machine Learning, Neural Networks, Deep Learning, Applied Mathematics, CI/CD Pipelines, Push Notifications, Apple Pay, Google Pay, Team Mentoring, Package Design, Payment APIs, Data Science, Vite, Large Language Models (LLMs), Audio Processing, Image Processing, Optical Character Recognition (OCR), Speech-to-Text (STT)
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