Frontend Developer - Web3/DeFi
Chmielna 73, Warszawa
10Clouds S.A
Position Overview
We are seeking an experienced Frontend Developer with deep expertise in Web3 and DeFi to join our engineering team. You will be responsible for building intuitive, secure, and high-performance user interfaces for blockchain applications, working with smart contracts, and creating seamless experiences for users interacting with decentralized protocols. This is a key role in shaping the future of our platform.
Key Responsibilities
Design and develop responsive, user-friendly frontend interfaces for Web3 and DeFi applications
Build interactive dashboards and tools that allow users to interact with smart contracts and blockchain data
Integrate with blockchain networks via Web3 libraries (ethers.js, web3.js) and wallet providers (MetaMask, WalletConnect, Ledger)
Implement real-time data streaming and updates from blockchain networks and protocols
Write clean, maintainable, and well-tested code with a focus on performance optimization
Collaborate with backend engineers, smart contract developers, and product teams to define UI/UX requirements
Implement security best practices specific to Web3, including transaction validation and wallet security
Optimize frontend applications for gas efficiency and blockchain transaction handling
Contribute to architectural decisions and technical documentation
Stay current with Web3 ecosystem developments, tools, and best practices
Required Qualifications
3+ years of professional frontend development experience
Proven expertise with React, TypeScript, and modern JavaScript (ES6+)
Strong understanding of blockchain fundamentals, smart contracts, and how DeFi protocols work
Hands-on experience building Web3 applications using Web3 libraries (ethers.js, web3.js, or equivalent)
Experience with wallet integrations (MetaMask, WalletConnect, or other Web3 wallet providers)
Familiarity with Ethereum and EVM-compatible blockchains
Experience with state management solutions (Redux, Zustand, Recoil, or similar)
Proficiency with CSS/styling solutions and responsive design
Version control with Git and collaborative development workflows
Strong problem-solving skills and attention to detail
Experience with testing frameworks (Jest, React Testing Library, Cypress, or similar)
Preferred Qualifications
Experience with multiple blockchain networks (Polygon, Arbitrum, Optimism, Solana, etc.)
Familiarity with popular DeFi protocols (Uniswap, Aave, Curve, Lido, etc.)
Knowledge of smart contract architecture and ability to read Solidity
Experience with GraphQL and subgraphs (The Graph protocol)
Experience with Next.js or other full-stack React frameworks
Understanding of Web3 security considerations and best practices
Contribution to open-source Web3 projects
Experience with blockchain explorers, Hardhat, or other development tools
Knowledge of NFT standards and marketplaces
Experience with hardware wallet integrations
Familiarity with performance monitoring and optimization tools
Technical Skills
Frontend Frameworks: React (required), Vue.js, Svelte, or similar frameworks
Languages: TypeScript, JavaScript (required)
Web3 Libraries: ethers.js, web3.js, wagmi, thirdweb SDK, or equivalent
Styling: Tailwind CSS, styled-components, Material-UI, or similar
Testing: Jest, React Testing Library, Cypress, or Playwright
Build Tools: Webpack, Vite, or similar
APIs: REST, GraphQL, JSON-RPC
Wallets & Providers: MetaMask, WalletConnect, Coinbase Wallet, Safe
Responsibilities Detail
Blockchain Integration
Implement wallet connection flows with proper error handling and user feedback
Manage Web3 provider interactions and RPC calls
Handle transaction creation, signing, and confirmation
Parse and display blockchain data (balances, contract state, transaction history)
Implement transaction monitoring and status updates
UI/UX Development
Create intuitive interfaces for complex DeFi operations (swaps, liquidity provisioning, lending/borrowing)
Design and build reusable component libraries
Implement real-time data visualization and charts
Ensure accessibility and mobile responsiveness
Optimize for various screen sizes and devices
Performance & Optimization
Optimize bundle sizes and load times
Minimize unnecessary blockchain queries and RPC calls
Implement efficient caching strategies
Identify and fix performance bottlenecks
Optimize gas estimation and display
Security
Implement input validation and sanitization
Handle sensitive data (private keys, secrets) securely
Validate transactions before signing
Implement rate limiting and abuse prevention
Keep dependencies up to date and monitor for vulnerabilities
What We Offer
Competitive salary
Flexible work arrangements (remote/hybrid)
Professional development budget
Health insurance
Collaborative, fast-paced environment working on cutting-edge technology
Opportunity to shape the future of decentralized finance
Mentorship from experienced Web3 developers

10Clouds S.A. is a verified Web3.0 enterprise and a leading software house recognized for its expertise in web development, mobile applications, web design, fintech solutions, machine learning, generative AI, blockchain,...
Frontend Developer - Web3/DeFi
Frontend Developer - Web3/DeFi
Chmielna 73, Warszawa
10Clouds S.A