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Web Development

5.0

(2 reviews)

Kostiantyn S.

@stadnichuk

5.0

2

3.5

3.5

100%

Full-Stack | Web 3 & Blockchain Developer

$35 USD / Hour

・

Ukraine (10:37 PM)

・

Joined on July 24, 2025

$35 USD / Hour

・

I build secure and scalable web and blockchain applications for startups and businesses. With 3+ years of full-stack experience in PHP (Laravel, CodeIgniter), JavaScript (Node.js, React.js), and blockchain (Ethereum, BNB Chain, Solana), I deliver everything from smart contracts and full-stack dApps to NFT marketplaces, staking platforms, and crypto payment integrations. I handle both backend and frontend development, as well as Web3 logic and deployment, so you get a complete solution from one developer.

Verifications

On time

100%

On budget

100%

Accept rate

100%

See all PHP Developers in Ukraine

Portfolio

Portfolio

I designed and deployed a full-scale automation system to manage multiple Twitter accounts with smart posting and analytics. The workflow leverages n8n for orchestration, Puppeteer + AdsPower + proxy rotation for automated posting, and Google Sheets for centralized reporting. Real-time monitoring updates run every 2–3 hours, providing accurate insights into engagement and growth.

Twitter&Instagram automation

Developed a Zapier workflow that monitors a remote FTP folder, uploads new files to Google Drive, extracts content using code steps, sends it to OpenAI (GPT) for processing, and auto-emails the result via Gmail. This system automates document parsing, AI-enhanced analysis, and report delivery with zero manual input.

FTP Document Processor

Dex Raiden is a fast, multichain DEX built for Ethereum and BSC, offering token swaps, liquidity pools, staking, bridging, and token creation. I developed and deployed smart contracts (router, factory, staking), created the frontend with wallet integration, and built custom subgraphs for real-time charts. The platform provides a seamless DeFi experience across chains

Multichain Decentralized Exchange

Developed a secure and scalable blockchain-based credential issuance and verification platform, inspired by solutions like CertOnce. The platform allows institutions (e.g., universities, companies, or certifying bodies) to issue tamper-proof digital certificates that can be instantly verified by third parties without relying on centralized authorities.

✅ Key Features Implemented:
Credential Issuance System:

Institutions can issue digital certificates (e.g., degrees, diplomas, experience letters) anchored on the Ethereum blockchain.

Each credential is hashed using SHA-256 and the hash is stored on-chain via a smart contract.

Instant Verification Portal:

Anyone (employers, universities, agencies) can verify the authenticity of a certificate by uploading or pasting the credential hash.

The system compares the hash to the one recorded on-chain and confirms its validity.

Decentralized Storage (IPFS):

Certificates are stored in IPFS to ensure permanent, distributed availability while

Blockchain-based Digital Credential

Developed a secure and scalable blockchain-based credential issuance and verification platform, inspired by solutions like CertOnce. The platform allows institutions (e.g., universities, companies, or certifying bodies) to issue tamper-proof digital certificates that can be instantly verified by third parties without relying on centralized authorities.

✅ Key Features Implemented:
Credential Issuance System:

Institutions can issue digital certificates (e.g., degrees, diplomas, experience letters) anchored on the Ethereum blockchain.

Each credential is hashed using SHA-256 and the hash is stored on-chain via a smart contract.

Instant Verification Portal:

Anyone (employers, universities, agencies) can verify the authenticity of a certificate by uploading or pasting the credential hash.

The system compares the hash to the one recorded on-chain and confirms its validity.

Decentralized Storage (IPFS):

Certificates are stored in IPFS to ensure permanent, distributed availability while

Blockchain-based Digital Credential

Developed a backend system using ASP.NET Core for managing restaurant services, including table reservations, order processing, and real-time kitchen updates. Implemented RESTful APIs with Entity Framework Core for database integration, ensuring scalability and maintainability. Focused on clean architecture, role-based access, and efficient data flow between front-of-house and kitchen staff.

ASP.NET Core Backend for Restaurant

Developed a backend system using ASP.NET Core for managing restaurant services, including table reservations, order processing, and real-time kitchen updates. Implemented RESTful APIs with Entity Framework Core for database integration, ensuring scalability and maintainability. Focused on clean architecture, role-based access, and efficient data flow between front-of-house and kitchen staff.

ASP.NET Core Backend for Restaurant

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

I designed and deployed a full-scale automation system to manage multiple Twitter accounts with smart posting and analytics. The workflow leverages n8n for orchestration, Puppeteer + AdsPower + proxy rotation for automated posting, and Google Sheets for centralized reporting. Real-time monitoring updates run every 2–3 hours, providing accurate insights into engagement and growth.

Twitter&Instagram automation

Developed a Zapier workflow that monitors a remote FTP folder, uploads new files to Google Drive, extracts content using code steps, sends it to OpenAI (GPT) for processing, and auto-emails the result via Gmail. This system automates document parsing, AI-enhanced analysis, and report delivery with zero manual input.

FTP Document Processor

Dex Raiden is a fast, multichain DEX built for Ethereum and BSC, offering token swaps, liquidity pools, staking, bridging, and token creation. I developed and deployed smart contracts (router, factory, staking), created the frontend with wallet integration, and built custom subgraphs for real-time charts. The platform provides a seamless DeFi experience across chains

Multichain Decentralized Exchange

Developed a secure and scalable blockchain-based credential issuance and verification platform, inspired by solutions like CertOnce. The platform allows institutions (e.g., universities, companies, or certifying bodies) to issue tamper-proof digital certificates that can be instantly verified by third parties without relying on centralized authorities.

✅ Key Features Implemented:
Credential Issuance System:

Institutions can issue digital certificates (e.g., degrees, diplomas, experience letters) anchored on the Ethereum blockchain.

Each credential is hashed using SHA-256 and the hash is stored on-chain via a smart contract.

Instant Verification Portal:

Anyone (employers, universities, agencies) can verify the authenticity of a certificate by uploading or pasting the credential hash.

The system compares the hash to the one recorded on-chain and confirms its validity.

Decentralized Storage (IPFS):

Certificates are stored in IPFS to ensure permanent, distributed availability while

Blockchain-based Digital Credential

Developed a secure and scalable blockchain-based credential issuance and verification platform, inspired by solutions like CertOnce. The platform allows institutions (e.g., universities, companies, or certifying bodies) to issue tamper-proof digital certificates that can be instantly verified by third parties without relying on centralized authorities.

✅ Key Features Implemented:
Credential Issuance System:

Institutions can issue digital certificates (e.g., degrees, diplomas, experience letters) anchored on the Ethereum blockchain.

Each credential is hashed using SHA-256 and the hash is stored on-chain via a smart contract.

Instant Verification Portal:

Anyone (employers, universities, agencies) can verify the authenticity of a certificate by uploading or pasting the credential hash.

The system compares the hash to the one recorded on-chain and confirms its validity.

Decentralized Storage (IPFS):

Certificates are stored in IPFS to ensure permanent, distributed availability while

Blockchain-based Digital Credential

Developed a backend system using ASP.NET Core for managing restaurant services, including table reservations, order processing, and real-time kitchen updates. Implemented RESTful APIs with Entity Framework Core for database integration, ensuring scalability and maintainability. Focused on clean architecture, role-based access, and efficient data flow between front-of-house and kitchen staff.

ASP.NET Core Backend for Restaurant

Developed a backend system using ASP.NET Core for managing restaurant services, including table reservations, order processing, and real-time kitchen updates. Implemented RESTful APIs with Entity Framework Core for database integration, ensuring scalability and maintainability. Focused on clean architecture, role-based access, and efficient data flow between front-of-house and kitchen staff.

ASP.NET Core Backend for Restaurant

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

This solution enables real-time remote control of a computer by combining three core technologies:

RTSP Streaming:
Provides a live video feed of the remote computer's screen using the Real-Time Streaming Protocol (RTSP), allowing the operator to visually monitor the system in real time with minimal latency.

WebSocket Communication:
Enables low-latency, bi-directional messaging between the client and server, used for transmitting control commands (such as keyboard/mouse input, gestures, or UI actions) from the remote device to the target computer.

HID (Human Interface Device) Driver Integration:
At the remote system level, a custom HID driver captures WebSocket input and emulates physical keyboard and mouse events, enabling full user input simulation even in low-level or secure system contexts (e.g., login screen, UAC prompts).

Use Cases:

Secure remote administration

Remote desktop over low-bandwidth connections

Headless system control (e.g., servers, kiosks)

Remote training or

Remote Computer Control Solution Usi

5.0 · 2 Reviews

Reviews

M

Automated Dropshipping Setup for Shopify Store • $450 AUD

Amazing work, delivered on time. Not a single thing that made me second guess my choices for choosing him as my freelancer.

Web Development

+3 more

Matthew G.

@matthew499

•

Cianrs, Australia

•

16 days ago

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Master's degree. Automation and computer-integrated technologies

2015 - 2020

•

5 years

Ukraine

2015 - 2020

•

5 years

Freelancer Orientation

P

Preferred Freelancer Program SLA

AI Training - Freelancer Global Fleet