zeljko4dev

Web3 Blockchain Developer | Solana | Ethereum | Rust | Solidity

Senior Blockchain Architect & Full-Stack Developer | Fintech, Crypto & DeFi

Expert Software Architect with 20+ years of experience and a Master of Information Technology. I design and deliver secure, scalable architecture for fintech, crypto, and decentralized finance projects - from smart contracts and token systems to complete DeFi platforms and presale infrastructure.

Passionate about clean, efficient code and enterprise-grade solutions. Fully dedicated to achieving 100% client satisfaction on every project.

✅ Blockchain development
✅ Solidity
✅ Rust
✅ Smart contracts
✅ Solana
✅ Ethereum
✅ Web3
✅ NFT
✅ Crypto
✅ ERC-20
✅ ERC-721
✅ SPL
✅ React.js
✅ Backend development
✅ API integrations
✅ Web development
✅ PHP
✅ Plugin development
✅ Payment Gateway Integrations
✅ API development
✅ Web applications
✅ Javascript
✅ Mysql
✅ Linux

#blockchain #blockchainarchitecture #solidity #rust #smartcontracts #solana #ethereum #defi #fintech #web3

Experience: 2 years

Yearly salary: $0

Hourly rate: $40

Nationality: 🇭🇷 Croatia

Residency: 🇭🇷 Croatia

Experience

Blockchain Developer | Rust | Solidity | Smart Contracts | Crypto | Solana | Ethereum

Freelance

2024 - 2026

Designed and developed decentralized applications (dApps) on Solana (Rust) and Ethereum (Solidity), delivering full-stack solutions using Node.js (backend) and React.js (frontend). Built and launched a crypto affiliate platform supporting presale campaigns for meme coins. Engineered smart contracts to automate commission splitting between investors, vendors, platform operators, and affiliates, ensuring transparent and secure fund distribution. Integrated mobile wallet support via WalletConnect, Phantom, and Solflare. Delivered production-ready code with a focus on scalability, security, and cross-chain compatibility.

Web Developer

Freelance

2011 - 2026

Working as a freelance Web developer. Some of the projects I've been working on: 1. quantumplr.com, membershops.com, idplr.com and indigitalworks.com Working as a backend developer on a Laravel multi-tenant e-commerce platform. - PHP Laravel framework - MySQL database - Redis Queue - Web Sockets - JQuery - HTML5 + CSS - aMember + WordPress API integration 2. voicecrafters.com - Voice actors marketplace Working as a backend developer on a WordPress platform. - PHP - MySQL database - JQuery - HTML5 + CSS 3. Interactive React/Laravel web application for managing and planning marketing campaigns (https://www.nextcampaign.com) - React.js Frontend - SVG graphics - Laravel Backend - MySQL database - AWS installation (EC2, RDS - MySQL, Load balancer, Certificate manager, Route 53 for domain administration) 4. Revolut banking API integration and invoice-creating software - PHP Slim framework - MySQL database - JQuery - HTML5 + CSS - Revolut API integration Other stuff related to my work can be seen on my website or my LinkedIn/Upwork profiles.

Java Developer

NTH Group

2004 - 2011

Java development of server-side telecom applications (SMS, Voice, WAP, etc.) - custom in-house frameworks - GlassFish - desktop application in Java for building SMS/MMS/Voice services

Skills

api

backend

blockchain

erc-20

erc-721

ethereum

fintech

mern

nft

node

postgres

react

rust

solana

tokenomics

web3

solidity

english

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