Staff Backend Engineer
Hands-on staff-level backend IC building the hardest parts of The Vault, an MPC-based crypto custody platform: policy engine, signing orchestration, key lifecycle, recovery flows, and multi-tenant SaaS services. Core stack is modern systems languages (Go preferred) with gRPC, Postgres, Kafka/NATS, plus AI-assisted development (Claude Code, Cursor, Codex). Fully remote with EU/CIS hours overlap.
- Compensation
- Not disclosed
- Location
- Remote
- Work setup
- Remote
- Seniority
- Staff
- Employment
- Contract
- Experience
- 3+ years
- Category
- Backend
- Posted
Skills
Must have
- Strong CS fundamentals: concurrency, distributed systems, consistency models, networking, OS behaviour
- Ownership mindset; owned non-trivial production systems end-to-end (design, ship, measure, improve, on-call)
- 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)
- Hands-on Go experience, or genuine readiness to ramp on Go in the first month
- Track record of Staff-level technical leadership through code, RFCs, and influence without formal authority
- Proven track record building high-load, multi-tenant SaaS in production (HA, incident response, SLOs)
- 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
- Production-grade use of modern AI coding tools (Claude Code, Cursor, Codex, or comparable) with the ability to critically review AI-generated code
- Clear written communication: design notes, RFCs, incident write-ups, trade-offs
- Mentorship of senior engineers
Nice to have
- 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
- 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
Full description
About us
The Vault, an MPC-based crypto custody platform for institutional and retail customers. We run threshold signing with non-extractable key shares across HSM and Ledger hardware, support a growing surface of chains and assets, and are pushing toward post-quantum readiness and SaaS-grade scale. Series A is ahead, the 2026 productized launch is in flight, and we publish original cryptographic research alongside the product work.
About the role
We're hiring a Staff Engineer to design, build, and ship the custody platform's hardest backend code. This is a hands-on IC role with real technical leadership: you write production code every day, own non-trivial cross-cutting initiatives, lead through RFCs and code, and mentor senior engineers — without managing people.
You shape architectural decisions in your work area through code, RFCs, and design reviews. Platform-wide architectural ownership (technology stack, core/periphery boundary, deployment models, post-quantum migration) sits with our technical leadership — you contribute to those decisions strongly, but you don't own them. If you want a role with the architecture-function hammer, this is not it. If you want a role where your code, your designs, and your judgment are the strongest signals in the room, it is.
We're hiring on the bet that engineering judgment, CS fundamentals, and ownership mindset matter more than specific language fluency in an AI-assisted era. We use Claude Code, Cursor, and Codex heavily. What we need is the depth to read AI-generated code critically — to catch the subtle concurrency, consistency, or security bugs that AI doesn't — and the ownership to drive non-trivial initiatives from idea to production reliability.
Both Staff Engineers on the team (this role and the Fullstack role) contribute across the codebase, with natural gravitation over time toward either the security-critical core (MPC library, threshold signing, HSM and Ledger integration, key lifecycle, cryptographic primitives) or the faster-moving periphery (chain and asset adapters, partner integrations, recovery and policy flows, APIs and SDKs).
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.