Senior Staff Backend Engineer

• Design, write, and ship critical custody-platform components including policy engine, signing orchestration, key lifecycle workflows, recovery flows, approvals, audit trails, and multi-tenant wallet and account services.
• Lead non-trivial cross-cutting initiatives through written RFCs, design reviews, and code.
• Build high-load, multi-tenant SaaS systems with tenant isolation, quotas, rate limits, backpressure, concurrency control, and predictable latency under spikes.
• Implement distributed-systems reliability patterns including idempotency, retries, outbox/inbox, event-driven workflows, sagas, state machines, replay, and graceful degradation.
• Apply security-by-design practices including least privilege, secret handling, mTLS/JWT, tamper-evident logs, and audit-ready data models for SOC 2, ISO 27001, and DORA scope.
• Improve performance and data systems through profiling, load testing, benchmarking, contention analysis, GC tuning, relational modelling, migrations, and indexing.
• Use Claude Code, Cursor, and Codex for production development and contribute to AI engineering practices.
• Set patterns and shared libraries for owned services; raise engineering standards through code review and example.
• Own features end-to-end from RFCs and code through tests, observability, rollout, and on-call.
• Mentor senior engineers through reviews and written designs.

• Strong CS fundamentals — reason from first principles about concurrency, distributed systems, consistency models, networking, and OS behaviour; understand locks and channels beyond the API level.
• Ownership of non-trivial production systems end-to-end: design, ship, measure, improve, and on-call.
• 10+ years backend engineering experience, 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, including HA, incident response, and SLOs.
• Hands-on experience with gRPC/HTTP, queues/streams, caching, relational databases, and Kafka/NATS or equivalent.
• Strong unit, integration, and contract testing discipline; testability-first design and deterministic CI.
• Strong observability habits: structured logging, metrics, tracing, and end-to-end production debugging.
• REQUIRED: production-grade use of modern AI coding tools such as Claude Code, Cursor, Codex, or comparable.
• Ability to critically review AI-generated code and avoid shipping code not understood by the candidate.

• A Staff IC role with real technical leadership — no people management, no sprint mechanics gauntlet, no architecture-by-committee.
• An AI-forward engineering culture with budget and autonomy for the tooling, models, and agents you need.
• Direct peers in cryptography research, security architecture, product, and delivery — you're not the only senior voice in the room.
• 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