✔ Blockchain Solidity, Truffle, Hardhat, Solana ✔ Web React.js, Vue.js, javascript, and jQuery ✔ Back-end Node.js, Express.js, Nest.js, PHP, Laravel, Socket.io, WebRTC, RESTful API ✔ Mobile App Dev React Native, Swift, Objective C, Android, Java, Kotlin, Flutter ✔ Database MySQL, PostgreSQL, MongoDB, SQLite