Сергій Ветеран

Serhii Markov
Full Stack Web & Mobile
Developer

SUMMARY
Full Stack Web & Mobile Developer specializing in modern web apps,
Telegram Mini Apps, and blockchain-integrated platforms. I build scalable,
user-focused solutions using React, Next.js, TypeScript, and Node.js —
seamlessly connecting web experiences with mobile technologies like
React Native and Expo. Passionate about clean architecture, teamwork,
and creating products that truly engage users.

CONTACTS
LinkedIn
email:[открыть контакты](см. выше в блоке «контактная информация»)
tel: [открыть контакты](см. выше в блоке «контактная информация») PROJECTS
Realtors
TECH SKILLS Role: Frontend Developer
Mobile application which implements the ability to search
Frontend for the purchase, rent, sale of real estate, and it is
also a platform for the work of Realtors. This project uses
React.js (3+ years)
the next technologies:
React Native + Expo (3+ years) React Native, React-hooks, Classnames, Axios,
TypeScript (2+ years) react-hook-form, expo, react-native-community/hooks
.
PWA (3+ years) OSBB
Next.js (1+ years) Role: Frontend Developer
PWA which implements the ability to manage a residential
Tailwind CSS (1+ years) building. Allows:
Redux (3+ years) users to easily find the information they need;
reduce energy consumption;
WebSocket (3+ years) keep a commercial bookkeeping office;
Backend share information, discuss and make decisions related;
control access to the house;
Node.js (2+ years)
This project uses the next technologies: React.js, PWA,
Express.js (2+ years) TypeScript, Redux, Classnames, Axios, react-hook-form,
MongoDB (2+ years) Jest.

Firebase(2+ years) Chat
Testing Role: Frontend Developer
Allows: the creation of group chats, exchange of messages,
Jest(2+ years) ability to search and send contacts, integration with
Other other corporate programs.
This project uses the next technologies: React.js, PWA,
@MUI TypeScript, Classnames, Axios, react-hook-form,
DaisyUI Jest, WebSocket, Mattermost API.
Formik
OS.comunity
Figma Role: Full Stack Developer
Classnames A mobile application designed to facilitate communication within closed
communities, enabling residents to exchange information, coordinate
TON Connect 2.0 events, and interact conveniently.
Telegram SDK Technologies: React Native(Expo), TypeScript, Firebase: Authentication,
Storage, Realtime Database and Cloud Firestore, Redux, ReactNativePaper,
Mattermost API react-native-custom-qr-codes-expo and others.
HTML, CSS ( LESS, SASS),
GrinG
Git Role: Full Stack Developer
The Telegram Mini App allows users to invest in real businesses and earn

SOFT SKILLS points. The app supports TON payments integration, a referral system, and
a rewards mechanism.
Industrious Technologies: React.js, Next.js, TypeScript, Tailwind CSS, MongoDB,
Telegram Mini App SDK, TON Connect 2.0, Axios.
Effective communication
Problem-solving mindset Asparagus Store
Role: Full Stack Developer
Self-management A website for selling fresh asparagus in Ukraine with a fully functional online
Flexible store, recipes, and administrative features. Implemented a product catalog,
order modals, responsive design, internationalization (Ukrainian/English), feedback
Quick learner forms with EmailJS integration, and SEO optimization.
Successful work as a team player Technologies: React.js, Next.js, TypeScript, Tailwind CSS, MongoDB,
Telegram Mini App SDK, TON Connect 2.0, Axios.
EDUCATION SUP.port
Kharkiv National University Role: Full Stack Developer
A Progressive Web App (PWA) for online booking of SUP boards and tours in Ukraine.
of Internal Affairs,
The project is localized (uk/en), SEO-optimized, and features Telegram and Firebase
qualification - lawyer | (2004- integrations, as well as smooth animations in the Apple Design style. It includes
2008) a PWA manifest, offline access for info pages, and modern UI.
Technologies: Next.js 15 (App Router, RSC), TypeScript 5, Tailwind CSS 4,
LANGUAGE daisyUI 5, next-intl 4 (localization), react-hook-form 7 + Zod 4 (forms/validation),
Framer Motion 12 (animations), Firebase Admin SDK (Firestore), Axios, Vercel (Deployment).
Ukrainian — native
Russian — native
And many others
English — intermediate
 projects

OSBB

This app is designed to make managing your home as simple and efficient as possible. The
application offers a wide range of functions that will help control various aspects of ensuring
functioning. Key features include:
Monitoring of energy consumption: the application allows you to view the level of energy
consumption of the house and analyze consumption trends over a certain period. This will
help you reduce energy consumption and save money.
Heating management: the application allows you to conveniently manage your home's heating
system, ensuring a comfortable temperature and energy efficiency.
Scheduled Repairs and Maintenance: The app reminds you of scheduled repairs and
maintenance so you can complete them on time and avoid expensive repairs in the future,
and notifies the community about scheduled and unscheduled events.
Access control: the app allows you to control access to your home, such as opening a gate or
a door lock.
Interactive notifications: The app sends interactive notifications about new messages and
events.
Information about services and ordering repair or maintenance services directly from the
application.
Advertising goods or services directly to platform users.
Commercial accounting: The application provides an opportunity to keep commercial
accounting of the house, where you can control all financial transactions related to the house.
Common platform for residents: The application provides an opportunity to create a common
platform for residents where they can share information, discuss and make decisions related
to life in the house.

This project uses the next technologies: React.js, PWA, TypeScript, Redux, Classnames, Axios,
react-hook-form, Jest.

React.js enabled efficient organization and reuse of application components.
Thanks to strict typing, TypeScript improved the reliability of the code.
By enabling offline access, PWA allowed users to use the application without an internet
connection.
Classnames provided more flexibility to add classes to elements in code, improving readability
and comprehension.
Axios facilitated requests to the server for data retrieval and enabled me to monitor the
consumed internet traffic.
React-hook-form efficiently managed forms in the application and optimized form data processing
speed.
Jest, used for testing written code, ensured code quality and identified errors before the
application was released to users.
In this application, Redux is utilized for efficient and convenient management of the application
state (ensuring a single source of truth), simple processing of actions, and a convenient method
for restoring the previous state in case of errors.
 projects

Realtors

An application that allows you to search, buy, rent and sell real estate. Also, the application is
a platform for the work of realtors, which allows them to effectively use the application to find
potential clients and conclude deals.
This app has several advantages over other apps for finding, buying, renting and selling real
estate:
A wide selection of real estate. The application offers a wide selection of properties for sale, rent
and purchase to suit all tastes and budgets, offering not only residential properties but also
commercial properties, land plots and other types of properties.
Efficiency. The application allows you to quickly and efficiently find the right real estate and
conclude deals, which saves users time and effort.
The platform for realtors. The application provides an opportunity for realtors to offer their
services and effectively interact with potential customers.
Intuitive interface. The intuitive interface makes it easy to find the property you need and make
deals.
Security. The application provides a high level of security, which is especially important when
concluding real estate transactions.
During development, React Native was used, which made it possible to create a cross-
platform dock for iOS and Android. React-hooks are used to work with components, which
allow us to effectively work with the life cycle of components. We use the Classnames library to
manage classes, which made it easy to add and remove classes from components.
The Axios library is used to communicate with the server, which allows you to make requests
to the API and get the necessary data. To create forms, we use the react-hook-form library,
which allows you to easily create and validate forms.
Also, Expo was used for development, which made it possible to quickly and efficiently
develop the application, without the need to install and configure the development
environment.
React-native-community/hooks is a React hooks library that has helped to implement certain
features in the application faster, reducing the time needed to write the code, reducing its
complexity and improving its readability.
This library contains a set of useful hooks such as useBackHandler, useFocusEffect, useNetInfo,
useOrientation, usePermissions, useSafeArea, useScrollToTop, useStatusBar, useToggle and
others.
They were used for:
Preserving component state between renderings.
Running effects after the component is loaded.
Access to certain functions, such as changing screen orientation, reading network status,
working with permissions, etc.
Support for collapsing the program when pressing the "Back" button.
Optimizing app performance with various tools like SafeArea, StatusBar, etc.

Jest - used for testing the written code, helped to ensure the quality of the code and detect
errors even before the application got into the hands of users.
 projects

Chat

The application was created to create group chats, exchange messages, provide access to
documents and other resources, the ability to search and send contacts, integration with other
corporate programs.
The advantage of using PWA technology is the speed of loading pages, the possibility of using
it without connecting to the Internet, the possibility of adding it to the main screen as an
application, less development costs, and the possibility of reuse.
This project uses the next technologies: React.js, PWA, TypeScript, Classnames, Axios, react-
hook-form, Jest, WebSocket, Mattermost API.
Using React.js made it possible to efficiently organize application components and reuse
them.
The use of TypeScript increased the reliability of the code, thanks to strict typing.
The use of PWA allowed users to access the application even offline.
Classnames allowed more flexibility to add classes to elements in code, making it easier to
read and understand.
Axios helped to make requests to the server to obtain data for your application and with its
help I developed the monitoring of the traffic of the consumed Internet.
React-hook-form provided efficient management of forms in the application and also
optimized the speed of form data processing.
Jest - used for testing the written code, helped to ensure the quality of the code and detect
errors even before the application got into the hands of users.
The application also used WebSocket and Mattermost API technologies to provide efficient
and continuous data exchange between the client and the server, which ensures high chat
performance and reliability.
WebSocket is a technology that allows you to establish a permanent connection between a
client and a server. In a chat application, WebSocket can be used to send messages between
chat users in real-time. That is when a user sends a message, it is immediately displayed on the
side of other users participating in the conversation.
The Mattermost API is an API that allows the chat application to interact with the Mattermost
server. Mattermost is a corporate communication system that provides the ability to create
closed chats for a team or project. In order to interact with Mattermost, a chat application may
use the Mattermost API to retrieve data about users, channels, messages, and other system
elements.
 projects

OS.community

OS.comunity is an innovative mobile application aimed at swiftly deploying a platform for
communication within a closed community. This application aims to unite residents of a specific
locality or area, providing them a convenient means of information exchange, coordination, and
interaction.
The functionality of the OS.comunity application includes the following features:
1. Chat: This is the primary tool for communication within the community. Users can exchange
messages one-on-one or in group chats, enabling convenient discussions on various topics,
event planning, and information sharing.
2. Community Events: Users can add and view information about community events. These
could include meetings, seminars, festivals, charitable actions, and other events of interest
to the community members.
3. Community News: The application offers quick access to news related to the community.
Users can learn about local events, receive updates on community-related information, and
stay informed about collective initiatives.
4. Creation and Discussion of Community Posts: This feature allows users to create posts on
the community's wall, sharing impressions, ideas, questions, and observations. Other
participants can leave comments and engage in discussions around these posts.
5. Information about Municipal Establishments and Useful Contacts: The application provides
access to a list of phone numbers and addresses of municipal establishments, taxis,
restaurants, and other useful contacts. This simplifies the task of finding necessary services
and establishments.
6. Searching for Orders for Various Services: Users can search for available orders for various
services, such as pet care, plumbing repairs, appliance repairs, and more. This can be useful
for those seeking specific services or offering them.
7. Top News Channels: The application allows users to receive the latest news from leading
information channels. This helps users stay informed not only about community events but
also about global events.
8. Weather Widget: The main screen of the application features a weather widget that provides
up-to-date information about weather conditions in the community's region.

During the development of the OS.comunity application, I utilized a stack of modern
technologies and tools to create a comprehensive and efficient platform. The development
process involved integrating various libraries and frameworks to achieve the desired
functionality. Here's a breakdown of the technologies and tools I employed:
1. React Native: I chose React Native as the core framework for building the application. This
allowed me to develop a single codebase that works on both iOS and Android platforms,
saving time and resources.
2. React Hook Form: To handle form management efficiently, I utilized the React Hook Form
library. This enabled smooth form validation and data handling within the application.
3. TypeScript: TypeScript was used to enhance code quality and maintainability by
introducing static typing to the project. This helps catch errors early in the development
process and improves the overall development experience.
 5. ReactNativePaper:
I incorporated ReactNativePaper to achieve a visually appealing and consistent UI design
throughout the application. This UI library streamlined the process of creating components
that adhere to Material Design guidelines.
6. react-native-gifted-chat:
To implement the chat functionality, I integrated the react-native-gifted-chat library. This
library simplified the process of building interactive and engaging chat interfaces within the
application.
7. react-native-vector-icons:
To enhance the visual elements of the app, I integrated react-native-vector-icons. This
allowed for easy integration of vector icons into various parts of the user interface.
8. expo-image-picker:
The expo-image-picker library facilitated the process of selecting and uploading images
within the application. This was particularly useful for features that involve user-generated
content.
9. react-native-custom-qr-codes-expo:
I integrated this library to enable the generation of custom QR codes within the application.
This functionality can be utilized for various purposes, such as event invitations or sharing
user profiles.
10. react-redux:
To manage the application's state in a scalable and organized manner, I incorporated react-
redux. This state management solution ensures efficient data flow and synchronization
between different components.
11. Firebase:
I leveraged various services from Firebase to enhance the application's backend capabilities:
Authentication: Firebase Authentication was used for secure user authentication and
authorization processes.
Storage: Firebase Storage enabled efficient storage and retrieval of user-generated
content, such as images and files.
Realtime Database and Cloud Firestore: These real-time databases were employed to
store dynamic and structured data, such as chat messages, user posts, and event
information.

In summary, OS.comunity is an advanced mobile application that brings residents of a specific
region or city closer together by offering them access to information, communication, and
services that enhance their daily lives.
 projects

GrinG

GrinG is an innovative multi-language mini-app on Telegram that allows users to build a
community where decisions on platform development are made through voting. GrinG uses its
own token on the TON blockchain, which serves as a tool for voting, rewards, and monetization.

Key Project Features
Development Voting:
Users vote with GrinG tokens to decide how the app will evolve.
Rewards:
Community members earn tokens for being active (voting, creating content,
participating in contests, and more).
Monetization:
Revenue will come from ads in the app, including social media profiles, other apps,
and promotions.
Reinvestment:
A portion of ad revenue will be reinvested into GrinG tokens to help maintain their
value.

Mining Mechanism:
Tokens can be earned by completing tasks in the app.
Mining limits will be set to control inflation and attract new users.

This project uses the next technologies: React.js, Next.js, TypeScript, Tailwind CSS, MongoDB,
Telegram Web Application SDK, TON Connect 2.0, Axios, React Context API, DaisyUI, Eslint,
Next-intl, react-confetti

🔗 Project Link: https://t.me/GrinG_official_bot/GrinG
 projects

Asparagus Store

Asparagus Store is a fully functional, responsive e-commerce website developed for the direct
sale of fresh asparagus and related products to the end consumer in Ukraine. The project
provides an efficient platform for the farm, allowing them to publish details about the harvest,
accept orders, and provide valuable content (recipes) to enhance customer engagement.

Key Project Features
E-commerce and Product Catalog:
Streamlined Ordering: Intuitive order modals allow customers to quickly finalize
purchases, simplifying the transaction process.
Dynamic Catalog: Clear presentation of seasonal asparagus varieties and other
products with high-quality images and detailed descriptions
Design and User Experience (UX):
Responsive Design (Mobile-First): The website works flawlessly on any device (desktop,
tablet, mobile), ensuring a consistently high user experience level.
Internationalization (next-intl): Full support for Ukrainian and English languages,
expanding the potential audience and simplifying access for international partners.
Modern UI/UX: Utilization of the DaisyUI library to create a clean, modern, and
aesthetically pleasing interface that aligns with the fresh produce theme.
Integration and Functionality:
Feedback Forms (EmailJS): Integration for immediate processing of customer inquiries,
questions, and suggestions, ensuring a fast and reliable communication channel.
Maps and Contacts (Google Maps API): Embedded map to conveniently display the
farm/pickup locations and detailed contact information.
Performance and SEO:
SEO Optimization: The project is developed with modern SEO requirements in mind
(utilizing Next.js 14 App Router), ensuring fast indexing and high search engine
rankings for targeted queries.
High Performance: Leveraging Next.js static generation and server-side rendering
to ensure lightning-fast loading speeds and smooth page transitions.

This project uses the next technologies: React.js, Next.js 14 (App Router), TypeScript,
Tailwind CSS, DaisyUI, MongoDB, next-intl (Localization), EmailJS, Google Maps API,
Vercel(deployment)

🔗 Project Link: https://asparagus-cherkasy.vercel.app/
 projects

SUP.port

SUP.port Cherkasy is a modern Progressive Web App (PWA) designed to provide a seamless
online booking experience for SUP boards and organized tours in Cherkasy. The project is
engineered for high performance, excellent user experience across all devices, and efficient
management of bookings, leveraging cutting-edge web technologies and cloud services.

Key Project Features
Progressive Web App (PWA) Capabilities:
Offline Access: Core informational pages remain accessible even without an
internet connection, enhancing reliability for users on the go.
Installability: Users can install the PWA directly onto their mobile devices
(iOS/Android) for quick access and an app-like experience without needing an
app store.
PWA Manifest: Configured to ensure proper PWA behavior, including custom splash
screens and full-screen display.
Design and User Experience (UX):
Apple Design Style: Implementation of smooth, aesthetically pleasing animations
and a clean UI/UX inspired by Apple's design principles, powered by Framer Motion 12.
Localization (next-intl): Full support for Ukrainian and English languages, catering
to both local residents and tourists.
Modern UI: Built with Tailwind CSS 4 and DaisyUI 5 for a responsive, modern,
and easily maintainable user interface.
Integration and Backend:
Booking and Data Management: Utilizes Firebase Admin SDK (Firestore) for robust
and scalable management of booking data, user sessions, and service information.
Communication & Notifications: Integration with Telegram for real-time notifications
to administrators regarding new bookings or inquiries, streamlining operational
efficiency.
Form Handling: Robust form management and validation using react-hook-form 7
paired with Zod 4 for secure and reliable data submission.
Performance and SEO:
SEO Optimization: Designed for high search engine visibility, crucial for attracting
customers searching for local activities and tours.
High Performance: Built on Next.js 15 (App Router, RSC) and TypeScript 5,
ensuring superior speed, reduced bundle sizes, and optimal performance
through React Server Components.

This project uses the next technologies: React.js, Next.js 15 (App Router, RSC), TypeScript 5,
Tailwind CSS 4, DaisyUI 5, Framer Motion 12, Firebase Admin SDK (Firestore), Axios,
next-intl (Localization), react-hook-form 7, Zod 4, Google Maps API, Telegram API (for
notifications), Vercel(deployment).

🔗 Project Link: https://sup-port.vercel.app/