Blockchain Software Engineer – Crypto Custody Platform

About the role

We are building a financial‑technology platform that lets institutional customers manage fiat accounts, transactional wallets and digital‑asset custody wallets. We need a backend‑focused Software Engineer with blockchain expertise to work across our existing web application and help create the next generation of our custody infrastructure.

Key responsibilities

• Develop and maintain features in our NestJS API, Next.js portal and supporting services.
• Design provider‑neutral custody workflows and evolve transaction systems toward immutable, policy‑controlled intents.
• Implement approval workflows, segregation of duties, transaction limits and destination policies.
• Build key‑set, wallet‑address and lifecycle management, integrating secure MPC, HSM or confidential‑computing components.
• Expand blockchain support across EVM networks and eventually Bitcoin and Solana.
• Improve Harbor, our blockchain observation and reconciliation service, and integrate providers such as QuickNode.
• Handle deposits, withdrawals, confirmations, finality, failed transactions and blockchain reorganisations.
• Design reliable asynchronous workflows using queues, idempotency and transactional outbox patterns.

Required profile

• Approximately 4+ years of professional software engineering experience or equivalent impact.
• Strong communication skills with the ability to explain technical trade‑offs clearly.

Required skills

• TypeScript and Node.js (NestJS, Next.js).
• PostgreSQL and relational database design, migrations and transactions.
• Authentication, authorization, role‑based access control and secure API design.
• Automated testing (unit, integration, end‑to‑end) for business‑critical workflows.
• Understanding of production blockchain systems: wallet addresses, transaction construction, signing, broadcasting, confirmations and reorganisations.
• Experience with EVM networks, ERC‑20 token transfers, JSON‑RPC APIs and blockchain indexing.