Staff Backend Engineer

The Vault is an MPC-based crypto custody platform for institutional and retail clients, scaling toward Series A. We’re looking for a Staff Engineer to design and ship the hardest backend code in the platform. This is a hands-on IC role with real technical leadership and no people management. You’ll build critical components such as signing orchestration, the policy engine, key lifecycle and recovery flows, and multi-tenant wallet services. You’ll lead initiatives in your area through RFCs, design reviews and code, and mentor senior engineers. Depending on your interests, you’ll focus either on the security-critical core (MPC, HSM/Ledger) or on chain adapters, integrations and APIs. We’re looking for someone with 10+ years in backend, including 3+ years at Staff level, strong CS fundamentals and experience building high-load multi-tenant SaaS. We expect strong production experience in Go or another systems language, plus production-grade use of AI coding tools, with the habit of reviewing AI-generated code critically. Exposure to custody, MPC/HSM or multiple blockchains is a plus.