Blockchain Engineer

Blockchain Engineer – Mainnet, Wallets & Regulatory IntegrationsOn-site / Hybrid – Barcelona | Fintech & Crypto InfrastructureWe are a fast-growing fintech startup expanding our Blockchain Engineering team.We're looking for a hands-on Blockchain Engineer to work on mainnet integrations, wallet security, and smart-contract interactions in a regulated production environment.This role operates at the intersection of blockchain technology and regulation, including MiCA, Travel Rule, and compliance-driven transaction flows.What you'll doBlockchain & Mainnet OperationsIntegrate and maintain mainnets (Ethereum / EVM chains and others as required).Manage RPC providers, node connections, confirmations, reorg handling and monitoring.Implement deposit / withdrawal flows with compliance-ready tracking.Wallets & SecurityWork on hot/cold wallet infrastructure, signing services and key management.Apply security best practices for fund custody and transaction execution.Coordinate with Security and Com...