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.