Senior Blockchain Engineer
7+ years building production systems across blockchain, fintech and enterprise backends - custody & wallet infrastructure, tokenization platforms and multi-chain integrations for startups and regulated financial institutions. Based in Poland 🇵🇱, working globally.
Key management and signing flows (KMS/HSM), multisig & MPC coordination, policy engines, transaction lifecycle & reconciliation, deposit detection across BTC, EVM and Solana.
Rust / Anchor, Token-2022, SPL & ATA flows, Squads Multisig, Meteora CP-AMM, Jupiter Swap, Helius RPC - token infrastructure end to end.
Solidity, ERC-20/4337 account abstraction, stablecoin payment rails (USDC/USDT), Wagmi / Viem, WalletConnect, fiat on/off-ramp integrations.
Hyperledger Besu / GoQuorum (QBFT), Canton Network (Daml), Firefly middleware, Kaleido - permissioned networks for financial institutions.
Java / Spring Boot microservices, TypeScript / NestJS, event-driven architectures, ledger design, high-integrity transactional systems.
Multi-agent development workflows, MCP servers and automation pipelines - with the judgement to critically review and verify AI-generated output.
Blockchain: Solana · Rust · Anchor · Solidity · Hyperledger Besu / GoQuorum · Canton / Daml · Firefly · Kaleido · EVM
Web3: Ethers · Wagmi · Viem · SIWE · ERC-4337 · WalletConnect · Hardhat · Foundry
Backend: TypeScript · NestJS · Node · Java · Spring Boot · Python
Data: PostgreSQL · RabbitMQ · Redis · IPFS · Liquibase
Infra: AWS · GCP · Kubernetes · Terraform · Docker · ArgoCD · Helm · Azure DevOps
The fastest way to reach me is LinkedIn. Open to senior blockchain / backend engineering engagements (B2B).