[Hiring] Staff Backend Engineer @The Vault

Role Description

The Vault is an MPC-based crypto custody platform for institutional and retail clients, running threshold signing across HSM and Ledger hardware. We're hiring a Staff Engineer to design and ship the custody platform's hardest backend code. This is a hands-on IC role with real technical leadership — no people management — where you drive non-trivial initiatives through code, RFCs, and mentorship.

You'll shape architecture in your area of ownership; platform-wide decisions sit with technical leadership. We're AI-forward (Claude Code, Cursor, Codex), and we need engineers who can read AI-generated code critically and catch what it misses — not just prompt it.

You'll naturally gravitate toward either the security-critical core or the faster-moving periphery.

What you'll do

• Design, write, and ship critical platform components: policy engine, signing orchestration, key lifecycle workflows, recovery flows, approvals, audit trails, multi-tenant wallet and account services.
• Lead non-trivial cross-cutting initiatives in your area — through written RFCs, design reviews, and code, not through hierarchy.
• Build high-load, multi-tenant SaaS systems: tenant isolation, quotas, rate limits, backpressure, concurrency control, predictable latency under spikes.
• Distributed systems & reliability: idempotency, retries, outbox/inbox, event-driven workflows, sagas and state machines, replay, graceful degradation.
• Security-by-design: least privilege, secret handling, mTLS/JWT, tamper-evident logs, audit-ready data models — designed for SOC 2, ISO 27001, and DORA scope from day one.
• Performance & data: profiling, load testing, benchmarking, contention analysis, GC tuning; strong relational modelling (Postgres or equivalent), migrations, indexing, clear consistency boundaries.
• AI-assisted development as a core competency: ship production code with Claude Code, Cursor, and Codex; build the prompt and agent patterns that work for your area; contribute to the company's AI engineering practices.
• Set patterns and shared libraries for the services your area touches; raise the bar through code review and example.
• Own features end-to-end: design notes / RFCs, code, tests, observability, rollout, on-call. No "throw it over the wall" handoffs.
• Mentor senior engineers: your reviews and your written designs are the strongest signal to the rest of the team.

Qualifications

• Strong CS fundamentals — reasoning from first principles about concurrency, distributed systems, consistency models, networking, and OS behaviour.
• Ownership mindset — owning non-trivial production systems end-to-end.
• 10+ years backend engineering, including 3+ years operating at Staff level (or equivalent senior IC scope).
• Strong production experience in a modern systems language — Go, Rust, Java, C++, or comparable.
• Track record of Staff-level technical leadership through code, RFCs, and influence.
• Proven track record building high-load, multi-tenant SaaS in production.
• Hands-on with modern backend stacks: gRPC/HTTP, queues/streams, caching, relational databases, Kafka/NATS or equivalent.
• Strong testing discipline: unit/integration/contract tests, testability-first design, deterministic CI.
• Strong observability habits: structured logging, metrics, tracing, end-to-end production debugging.
• REQUIRED: production-grade use of modern AI coding tools (Claude Code, Cursor, Codex, or comparable).

Requirements

• Exposure to custody, wallets, or signing systems (MPC, HSM, TEE, key management, approvals).
• Hardware wallet integration (Ledger).
• Multiple blockchain ecosystems (EVM and Bitcoin minimum; Cosmos, Solana, others a plus).
• Built custom agents, MCP integrations, or in-repo AI workflows that compounded a team's productivity.
• Designed and run evals for AI-generated code (correctness, security, style).
• Kubernetes and service mesh in production; SRE practices.
• Regulated-environment experience (fintech, security audits, compliance-driven engineering).
• Threat modelling and security review participation.
• Familiarity with SOC 2, ISO 27001, and DORA — enough to design for them.

Benefits

• Fully remote, any time zone with reasonable overlap with EU/CIS hours.
• Competitive comp at the Staff engineer band; equity participation; full benefits.
• A product approaching Series A with paying institutional customers and a published cryptographic research line.