Requirements
-Multi-protocol experience (strongly preferred)
-Java and SQL are required skills for all backend engineers. Some services within the platform use Python and Node.js, experience with either or both is preferred.
-Familiarity with test-driven development (TDD) and/or behaviour-driven development (BDD) as working practices, writing tests before or alongside implementation.
-Familiarity with Domain-Driven Design principles.
-Comfortable working in a monorepo structure with shared libraries, cross-squad code visibility, and coordinated CI/CD pipelines.
-Proactive communication, raising blockers, design concerns, and cross-squad dependencies.
-Written and verbal communication in English must be at professional level.
-Engineers may work remotely but must be available during core working hours (UK/Europe timezone overlap).
Technical requirements (specific)
-Backend platform engineering: Microservice architecture, API design (REST and/or gRPC), intent and event-driven systems, database design (Microsoft SQL Server and/or PostgreSQL)
-Governance and policy systems: Experience building or integrating rule engines, declarative policy languages, approval workflow systems, or compliance automation
-HD wallet and key management: Familiarity with BIP-32, BIP-44, BIP-84, SLIP-10, and BIP-39 standards. Understanding of hierarchical deterministic key derivation, xPub management, and derivation path structures across multiple chains
-Signing coordination: Understanding of multi-backend signing orchestration, routing requests to HSMs, managing multi-sig coordination state, handling timeouts and retries
-Infrastructure: Kubernetes, CI/CD pipelines, monitoring (Prometheus/Grafana or equivalent), infrastructure-as-code (Terraform or equivalent)
-Separation of concerns and component isolation: Strong understanding of plugin patterns, adapter interfaces, and clean boundary design. CORE builds the contracts and abstractions that asset squads implement, getting interface design wrong creates coupling that compounds across every chain. Experience designing extensible platforms where new chains or signers can be added without modifying core logic is essential.
-Reconciliation and balance verification: Experience building or integrating reconciliation systems, comparing internal ledger state against external sources, detecting discrepancies, and generating audit-ready evidence. Understanding of the reconciliation requirements of a regulated custodian (periodic balance proofs, transaction matching, discrepancy escalation).
-Audit trail and tamper-evident logging: Experience building immutable, cryptographically verifiable audit records for signing events and transaction lifecycle changes. Understanding of what regulators and auditors expect from a custody evidence trail, not just application logging, but provable records of what was authorised, signed, and executed.
-Event-driven architecture and notification design: Experience defining event taxonomies, publishing contracts, and consumer patterns for downstream systems. The platform must emit well-structured events (balance changes, transaction status transitions, deposit detections, policy decisions) that GX and operational tooling consume.
-Token and asset registry design: Experience modelling multi-chain, multi-token asset registries, token contract addresses, metadata (decimals, symbols), chain-specific identifiers, and tier classification structures that feed into policy evaluation.
-Blockchain data abstraction: Experience designing abstraction layers over chain data providers (RPC nodes, third-party indexers). The platform will initially leverage existing integrations for balance queries, transaction history, and address monitoring, but the abstraction must be clean enough to allow future internalisation without rewriting consumers.
Candidate's responsibilities
Policy engine, wallet registry, signing coordinator, HD wallet library, common infrastructure (API gateway, event bus, database schemas, monitoring)
Interview stages
Boosty HR + tech interview + TBD re client's tech interview