Senior Go developer

Workload: full-time, remote Start: asap Duration: long-term (6-12 months anticipated, final term TBD) Location: any (Europe timezone alignment) English: B2/C1 Working Hours: 8 hours/day | Core availability 10:00-17:00 UK time, with flexibility for overlap with Eastern Canada Hardware: Candidate may use their own laptop; VPN required for production changes or production-data investigation RESPONSIBILITIES Virtual Signer Engineering • Maintain and improve the Go Virtual Signer, including signing orchestration, communication between participants, encrypted storage, and recovery from failures. • Investigate concurrency, timeouts, interrupted sessions, network failures, and service restarts; review outstanding pull requests and address race conditions. • Improve logging and visibility, assess the existing implementation critically, and make careful, maintainable changes. • Support agreed transaction approval features and future post-quantum signature work. Cryptography, SDKs & Cross-Platform Integration • Maintain integrations with MPC and threshold-signature libraries, working with cryptography specialists where changes affect protocol security. • Contribute to shared SDKs and bindings connecting Go with Swift, Kotlin, and JavaScript/TypeScript. • Work with backend and mobile engineers to preserve API compatibility and consistent signing behavior across releases. Quality, Testing & Operations • Improve automated tests for signing correctness, failure recovery, and interoperability between virtual and mobile signers. • Support Linux and Docker deployments, dependency upgrades, monitoring, release processes, and operational documentation. Ownership & Technical Judgment • Take primary ownership of a security-critical codebase with limited handover and independently establish a robust production baseline. • Assess technical risks and trade-offs, explain decisions clearly, and make incremental changes with sound security judgment. • Collaborate pragmatically with backend, mobile, testing, and cryptography specialists across time zones. REQUIREMENTS !!! Essential Technical Experience • Strong hands-on production Go, including goroutines, channels, context cancellation, race detection, profiling, and resource management. • Experience owning production services, diagnosing complex failures, and delivering well-tested fixes. • Distributed-systems knowledge, including asynchronous messaging, retries, idempotency, state management, and partial failures. • Practical security engineering: authentication, encrypted storage, sensitive-data handling, and safe logging. • Applied cryptography concepts, including digital signatures, hashing, key management, and signature verification. • Automated testing, CI/CD, Linux, containers, and production observability. • Ability to understand an established codebase, make careful incremental changes, and explain technical decisions clearly. Strongly Preferred / Desirable Technical Experience • JavaScript/TypeScript SDKs and mobile bindings, including asynchronous APIs, packaging, compatibility, and Go/mobile interoperation. • React Native/Expo, Swift, or Kotlin; experience with mobile lifecycle, secure storage, or native modules. • MPC or threshold signatures, distributed key generation, and changes to signing participants. Blockchain transaction signing, including signing payloads and chain-specific requirements. • Confidential computing and hardware attestation, particularly AMD SEV-SNP, are especially valuable among the desirable skills. • MQTT, Protocol Buffers, Prometheus, or Open Telemetry; familiarity with post-quantum signature schemes is also desirable for the longer-term roadmap.