Oleksii Koval
Private message 
Offer work 
Kyiv,
Ukraine
available for hire
Rating
Language proficiency level
English: fluent
Українська: fluent
Русский: fluent
CV
About Our Company
We are The Dev Company, a team of four experienced developers who have united their knowledge and passion for innovation to create outstanding digital solutions.
Our journey began in Kyiv with a simple idea: to combine deep technical expertise with a creative approach to solving complex challenges. Today, we work with clients around the world while staying true to our Ukrainian roots and values of quality and reliability.
Our Mission
We create digital products that not only meet expectations — they exceed them. From concept to launch, each project is an opportunity to bring new ideas to life and push the boundaries of what’s possible in web development.
What Sets Us Apart
Full-cycle development: From frontend to backend, from idea to final product
Cutting-edge technologies: Specializing in AI integration and Web3 solutions
Global perspective: Operating 24/7 thanks to our distributed team
Ukrainian quality: High standards paired with competitive pricing
Our Expertise
Frontend development: Next.js, React, WordPress — building intuitive and fast user interfaces
Backend development: Python, Nest.js, APIs, GraphQL — creating robust architectures for your applications
AI & Machine Learning: Enhancing functionality and user experience through intelligent systems
Web3 & Blockchain: Solidity, smart contracts, decentralized apps — the future is already here
Our Values
Innovation: Always seeking new ways to solve problems
Quality: Every line of code undergoes thorough review
Partnership: Your success is our success
Transparency: Open communication at every project stage
Why Clients Choose Us
Our clients trust us because we don’t just complete technical tasks — we become part of their team. We understand business needs, offer optimal solutions, and are always ready to adapt to new challenges.
Ready to start your next project?
Whether you need a simple website, a complex web app with AI features, or an innovative Web3 solution — we’re ready to bring your ideas to life.
Skills and abilities
Programming
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AI & Machine Learning
from 271 USD for project
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Bot Development
from 113 USD for project
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Content Management Systems
from 158 USD for project
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Cryptocurrency & Blockchain
from 902 USD for project
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Databases & SQL
from 113 USD for project
- Gaming Apps
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HTML & CSS
from 180 USD for project
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Javascript and Typescript
from 226 USD for project
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Python
from 1353 USD for project
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Web Programming
from 226 USD for project
Design & art
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Interface Design (UI/UX)
from 271 USD for project
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Mobile Apps Design
from 271 USD for project
Services
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AI Consulting
from 135 USD for project
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Website Development
from 609 USD for project
Portfolio
- All works 4
- Javascript and Typescript 1
- Web Programming 1
- AI & Machine Learning 1
- Cryptocurrency & Blockchain 1
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3500 USD AI CRM – CRM system with AI-assistants using Vapi.ai
AI & Machine Learning
Development of a Full-Fledged AI CRM System with Vapi Integration for Voice Agents
Our team, The Dev Company, developed a comprehensive AI CRM system designed for automated client handling via telephony using Asterisk and integrated with Vapi.ai.
… Backend:
The backend was fully developed in Nest.js, with Vapi.ai and Asterisk integration, enabling the creation of AI assistants that call a provided list of phone numbers. The system supports automated client request handling, call scenario management, and detailed logging.
Frontend:
The frontend was implemented in Next.js, fully integrated with the backend, with authentication and role-based access (admin / user). The web application features:
– a dashboard for managing AI assistants and trunks;
– pages for leads and numbers for single or automated calls;
– real-time call monitoring;
– detailed logs of each call, dialogue transcription;
– call outcome evaluation (success/failure);
– ability to listen to recorded calls;
– and many other tools to control and optimize AI assistant performance.
Result:
A complete AI CRM system that efficiently automates client handling, increases contact center productivity, and provides full control over all calls and interactions.
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10 000 USD TradeLook – AI journal for trading
Javascript and Typescript
TradeLook — enterprise web application for traders
Technologies:
Frontend: Next.js, Material UI, authentication via Google and Passport.js
… Backend: NestJS, integration with crypto exchange APIs (Binance, Bybit) and MetaTrader, full development of own REST API.
AI: Integration with OpenAI API for generating personalized dashboards and textual explanations of trading statistics
Database: Firestore
Link: https://help.tradelook.io/en/
Main features:
– Authentication via Google (OAuth2)
– Connecting trader accounts to crypto exchanges through API keys
– Automatic loading of trade history
– Powerful analytics and visualization of trading metrics
– AI interface that allows creating queries like: "Show the most successful days of the week", "Generate the perfect dashboard for me"
– Ability to customize dashboards, save templates, and display statistics in real time
Role:
– Full development of the frontend in Next.js
– Building the backend in NestJS with integration of third-party APIs and OpenAI
– Implementation of authentication, secure handling of API keys, dynamic AI queries
– Architecture, deployment, support, and testing of the project
Complexity:
– Enterprise-level architecture
– Asynchronous processing of large volumes of financial data
– Working with sensitive information (API keys, analytics)
– AI-generated user interface structure depending on trading patterns
The project is ongoing, currently in closed testing.
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8000 USD Defaust Academy – web platform for learning
Web Programming
Defaust — an educational platform for traders
What has been done:
… — Full development from scratch, including design, architecture, and implementation of the entire platform.
— Tech stack:
— Frontend: Next.js (React) + Astro (combined for marketing pages and web application)
— Backend/API: Supabase (PostgreSQL + Auth + Edge Functions)
— Authentication: Supabase Auth with email/password and OAuth
— UI: Custom design system on Tailwind CSS
— Admin panel: separate part of the application with full CRUD interface for courses, articles, sections, tests, users
Key functionality:
— Public marketing part (on Astro): articles, landing page, SEO
— User personal account: courses, tests, progress
— Educational content divided into modules with access logic
— Registration/login, access to materials based on role
— Full admin panel for platform management — courses, access rights, users, content
— Webhooks, analytics, automation of updates
Our role:
— Architect and developer: development of the entire platform (frontend, backend, DevOps)
— Integration of all services (Supabase, OpenAI, Astro, Next.js)
— UI/UX design
— Building the logic of the educational process and access rights
— Continuous support and scaling of functionality
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12 000 USD MemeWars — Web3 on-chain game
Cryptocurrency & Blockchain
Stack: Solidity, Ethereum, Arbitrum, zkSync, Chainlink VRF, Thirdweb, Alchemy, Next.js, Webhooks
Description:
… MemeWars is a fully on-chain strategic game built on smart contracts for Ethereum, Arbitrum, and zkSync networks. Players compete for dominance over memes in an imaginary crypto universe, using tokens, NFTs, and PvP mechanics that operate entirely on the blockchain.
Team Role:
– Developed a complete architecture with 10+ interconnected smart contracts in Solidity (game logic, NFTs, tokenomics, PvP battles, staking mechanics).
– Integrated a randomness oracle via Chainlink VRF for fair randomness in battles.
– Used Thirdweb for convenient interaction with contracts on the frontend.
– Connected Alchemy for notifications and event monitoring via Webhooks.
– Developed a full frontend on Next.js with wallet connections (Metamask, WalletConnect).
– Ensured support for a multi-chain game (Ethereum, Arbitrum, zkSync).
Result:
All game logic, including battles, rewards, and NFT updates, operates fully on-chain without a centralized server.
Reviews and compliments on completed projects 8
1 April
197 USD
Corrections on bots
We have collaborated multiple times - and each time everything goes smoothly and with excellent results. You can always count on explanations and quick feedback. It is pleasant to work together.
27 March
101 USD
Integration of Google Sheets + Kajabi through the official Public API The Dev Company
We have been working together on multiple projects already — and every time the result is excellent. I appreciate that you always provide guidance, help to understand, and never leave questions unanswered. Very comfortable collaboration.
I am reaching out for the first time. Everything, as always, is at a high level. I will reach out again.
| Everything is great!!! This is the third time we are working with The Dev Company team. Very satisfied )
13 August 2025
293 USD
Understand and complete the project. CRM, VAPI, Asterisk FreePBX, NestJS framework, Node.js
Feedback on collaboration with The Dev Company
The work was done at the highest level – all points of the technical task were implemented clearly and professionally.
13 August 2025
271 USD
Understand and complete the project. Change CRM, VAPI, asterisk freePBX Frontend
Feedback on collaboration with The Dev Company
The work was done at the highest level – all points of the technical task were implemented clearly and professionally.
2 August 2025
45 USD
Telegram bot + Google Spreadsheet + WayForPay API
We are contacting Oleksii's team for the second time — and once again we are very satisfied with the result! The task was complex, with many nuances, integrating a Telegram bot, Google Sheets, and WayForPay, as well as additional requests that arose during the work process.
We especially want to highlight:
Patience and attentiveness — the team always responded calmly to all edits, explained each step in detail, answered all questions, and helped understand even those moments that went beyond the initial technical assignment.
Meticulous approach — all technical details were considered, the system's logic was implemented as clearly as possible, with a user-friendly interface, detailed instructions, and support at every stage.
Responsiveness — tasks were completed within the agreed deadlines, even when additional difficulties or requests arose.
Code quality — the solution works stably, is flexibly adjustable to our needs, and all integrations are implemented at a high level.
It is very pleasant to work with professionals who not only complete the tasks but also genuinely help improve the product! We definitely recommend collaborating with them — and are confident that we will turn to you again in the future!
Thank you for your work and human approach!
If you are also looking for responsible and professional performers for business process automation — feel free to contact this team!
30 July 2025
68 USD
API Nova Poshta
Feedback on collaboration with The Dev Company
The work was done at the highest level – all points of the technical task were implemented clearly and professionally. Automatic creation of TTHN, status updates, dropdown lists, validation, error protection – everything works stably and conveniently.
The team is very responsible and responds quickly – always in touch, promptly makes corrections, provides clear explanations. Very satisfied with the cooperation – it's a pleasure to work with professionals who truly know their craft.
Immediately after completing the first project, I handed over the second – so satisfied with the result.
I recommend! And I will definitely contact again!