Software Engineer in Blockchain - Crypto Custody Platform

We are building a financial technology platform that enables institutional customers to manage fiat accounts, transactional wallets and digital-asset custody wallets. We are looking for a backend-focused a Software Engineer with Blockchain Exposer who can work across our existing web application while helping us build the next generation of our custody infrastructure. You will work primarily with TypeScript, NestJS, Next.js and PostgreSQL. You will also help us evolve from relying entirely on third-party custody providers toward operating more of our own wallet, transaction-policy, blockchain-monitoring and secure-signing infrastructure. This is not a blockchain research or smart-contract-only role. We need a strong engineer who understands how production blockchain systems work for Digital Currency: wallet addresses, transaction construction, signing, broadcasting, confirmations, reorganizations and reconciliation. You will not be expected to invent a new MPC cryptographic protocol. You will be expected to help us safely integrate audited cryptographic components and build the platform around them.

Responsibilities:

• Build and maintain features across our NestJS API, Next.js portal and supporting services.
• Design provider-neutral custody workflows that can work with third party wallet infra provider and in near future DMG own internal signing infrastructure.
• Evolve our transaction system from simple quorum approvals into immutable, policy-controlled transaction intents.
• Implement approval workflows, authorization receipts, segregation of duties, transaction limits and destination policies.
• Build custody-space, keyset, wallet-address and key-lifecycle management.
• Integrate secure MPC, HSM or confidential-computing components without exposing key material to the main application.
• Build chain-specific transaction construction and broadcasting services.
• Expand blockchain support across EVM networks and eventually other families such as Bitcoin and Solana.
• Improve Harbor, our blockchain observation and reconciliation service.
• Integrate blockchain infrastructure providers such as QuickNode for RPC, streams and historical data.
• Handle deposits, withdrawals, confirmations, finality, failed transactions, replacements and blockchain reorganizations.
• Build reliable asynchronous workflows using queues, idempotency and transactional outbox patterns.
• Design secure administrative and disaster-recovery workflows for custody operations.
• Write unit, integration and end-to-end tests for sensitive financial workflows.
• Participate in architecture discussions, code reviews, operational planning and incident investigation.
• Document important technical and security decisions clearly.

Qualifications:

Approximately 4 or more years of professional software engineering experience, or equivalent demonstrated impact.

Required Skills:

• Strong TypeScript and Node.js experience.
• Experience building and operating production web applications and backend APIs.
• Experience working with relational databases, data modelling, migrations and transactions.
• Ability to work across backend services, integrations and frontend application code.
• Experience designing asynchronous and failure-tolerant workflows.
• Good understanding of authentication, authorization, role-based access and secure API design.
• Experience writing meaningful automated tests for business-critical workflows.
• Ability to understand an established codebase, follow its patterns and improve it incrementally.
• Strong communication skills and the ability to explain technical trade-offs clearly.

Preferred Skill:

• Building or integrating blockchain wallets.
• EVM transactions, chain IDs, gas, nonces and transaction receipts.
• ERC-20 token transfers and event logs.
• Blockchain JSON-RPC APIs.
• Signing and broadcasting raw transactions.
• Wallet address derivation and hierarchical deterministic wallets.
• Transaction confirmations, finality and reorganizations.
• Blockchain indexing, webhooks or event-stream processing.
• Deposit and withdrawal lifecycle management.
• Reconciliation between on-chain activity and an internal ledger.
• Custodial versus non-custodial wallet models.
• Hot, warm and cold-wallet security concepts.