Senior Smart Contract Developer – Pet360 (Blockcha

**About the Project** We are building Pet360 — the first blockchain-based pet ecosystem in Brazil. 160 million pets, $60 billion market, zero blockchain infrastructure today. Our Web2 platform is 75% complete. We are now building the Web3 layer from scratch — pet NFT passports, vaccine certificates, smart contract adoptions, and on-chain pet insurance. We are looking for a Senior Smart Contract Developer to join our team. **What You Will Do** - Write and deploy Solidity smart contracts (ERC-721 for pet passports, ERC-1155 for vaccine certificates) - Implement upgradeable contract patterns (UUPS) for future flexibility - Write comprehensive tests using Foundry or Hardhat - Optimize gas usage and ensure security best practices - Design the on-chain architecture for pet identity, vaccine verification, and insurance claims - Work alongside our backend and frontend teams **What We Are Looking For** - 3+ years of software development experience - 1+ year of Solidity and EVM development - Strong understanding of ERC-721 and ERC-1155 standards - Experience with Foundry or Hardhat - Understanding of smart contract security and gas optimization - Experience with upgradeable contract patterns (UUPS or Transparent proxies) - Professional English proficiency **Nice to have:** - Experience with multi-chain deployments (Polygon, Ethereum, BSC) - Experience with smart contract auditing - Experience with IPFS and decentralized storage - Experience with AI-assisted development (Cursor, Claude Code) **What We Offer** - Fully remote — work from anywhere - Contract with long-term growth potential - 30+ hours per week - $70-120 per hour (negotiable) - Founding team token allocation - Payment in crypto (USDC/USDT) or fiat (Wise/PayPal)