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.