Senior Backend Engineer

Spectrum Search is partnered with a digital asset infrastructure company building security-critical technology for institutional-grade systems. This is an opportunity for a senior backend engineer to own production services where correctness, security, durability and long-term API stability are fundamental. About the opportunityThe company is developing infrastructure that helps digital asset systems adopt more resilient cryptographic standards while maintaining reliable user and developer workflows.The engineering environment combines backend product development with applied cryptography and security research. The work includes production services, APIs, libraries, security controls and infrastructure designed for systems handling sensitive cryptographic operations.This is a full-time permanent position within a growing Product Engineering team. The roleYou will take end-to-end ownership of security-critical backend services, primarily using Rust and TypeScript.The role requires strong engineering judgement around secure system design, operational reliability, backward compatibility and auditability. You will work closely with cryptography and research engineers to translate new cryptographic approaches into robust production systems. Key responsibilitiesDesign, build and maintain production-grade backend services using Rust and TypeScriptOwn APIs and libraries with strict reliability and backward-compatibility requirementsDevelop systems that meet high standards for security, correctness and durabilityImplement secure approaches to signing, encryption, secrets management and key handlingTake ownership of service deployment, CI/CD pipelines and containerised infrastructureWork with cryptography and research engineers to move new cryptographic primitives into productionSupport long-lived infrastructure used within digital asset, identity or settlement environmentsContribute to systems designed with strong operational controls and auditability Essential requirementsSenior-level backend engineering experience building and operating security-critical production systemsStrong production experience with Rust, including services that have been shipped and maintained at scaleStrong TypeScript skills for backend services, APIs or librariesExperience within a digital asset or Web3 technology companyPractical experience building systems where security and correctness are critical, such as digital asset custody, key management, identity, payments or regulated infrastructureStrong understanding of applied cryptography fundamentals including signing, encryption, secrets management and secure key handlingProven ability to build performant backend services and APIs for production environmentsExperience owning CI/CD pipelines, containerisation and service deployment using technologies such as Docker and Kubernetes Nice-to-havesProduction experience with threshold signing, multi-party computation or hardware security module integrationKnowledge of post-quantum cryptography or experience migrating cryptographic primitives within live systemsExperience designing systems within SOC 2 or ISO 27001 environmentsFamiliarity with digital asset infrastructure including wallets, settlement systems and on-chain identityOpen-source contributions to cryptography, security or infrastructure projects Location and remote setupThis is a fully remote role for candidates based in Europe. The position is full-time and permanent.