You will build and maintain features across NestJS APIs, Next.js portals, and supporting services for an institutional digital-asset custody platform. You will design provider-neutral custody workflows, transaction policies, approval and authorization systems, wallet and key lifecycle management, blockchain transaction construction and broadcasting services, and asynchronous financial workflows. You will integrate secure MPC, HSM, confidential-computing, RPC, and blockchain infrastructure components; expand support across EVM, Bitcoin, and Solana networks; improve blockchain observation and reconciliation; manage deposits, withdrawals, confirmations, finality, failures, replacements, and reorganizations; and create secure administrative and disaster-recovery workflows. You will also write automated tests, participate in architecture discussions, code reviews, operational planning, and incident investigations, and document technical and security decisions.
Responsibilities
- Build and maintain features across the NestJS API, Next.js portal, and supporting services
- Design provider-neutral custody workflows for third-party and internal signing infrastructure
- Evolve transaction systems 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
- Build chain-specific transaction construction and broadcasting services
- Expand blockchain support across EVM networks and other blockchain families
- Improve the blockchain observation and reconciliation service
- Integrate blockchain infrastructure providers for RPC, streams, and historical data
- Handle deposits, withdrawals, confirmations, finality, failed transactions, replacements, and reorganizations
- Build reliable asynchronous workflows using queues, idempotency, and transactional outbox patterns
- Design secure administrative and disaster-recovery workflows
- Write unit, integration, and end-to-end tests for sensitive financial workflows
- Participate in architecture discussions, code reviews, operational planning, and incident investigations
- Document technical and security decisions
Requirements
- Approximately 4 or more years of professional software engineering experience or equivalent demonstrated impact
- Strong TypeScript and Node.js experience
- Experience building and operating production web applications and backend APIs
- Experience 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
- Understanding of authentication, authorization, role-based access, and secure API design
- Experience writing automated tests for business-critical workflows
- Ability to understand and improve an established codebase
- Strong communication skills
- Experience building or integrating blockchain wallets
- Knowledge of EVM transactions, chain IDs, gas, nonces, and transaction receipts
- Knowledge of ERC-20 token transfers and event logs
- Experience with blockchain JSON-RPC APIs
- Experience signing and broadcasting raw transactions
- Knowledge of wallet address derivation and hierarchical deterministic wallets
- Knowledge of transaction confirmations, finality, and reorganizations
- Experience with blockchain indexing, webhooks, or event-stream processing
- Knowledge of deposit and withdrawal lifecycle management
- Experience reconciling on-chain activity with an internal ledger
- Knowledge of custodial and non-custodial wallet models
- Knowledge of hot, warm, and cold-wallet security concepts