Full-Stack Engineer (Security)

Thispositionislistedonbehalfofapartnercompany,whomanagesallapplicationsandnextsteps.OurpartnerislookingforaFull-StackEngineer(Security)basedinCanada. Joinaremote-firstengineeringteambuildingcutting-edgeinfrastructureforsecure,cross-chainpaymentsandblockchaintransactions.AsaFull-StackEngineerspecializinginsecurity,youwillworkcloselywithsecurityleadershipandproductengineerstoprotectfinancialsystemsoperatingaroundtheclock.Youwilltakeownershipofcriticalsecurityservices,frauddetectionmechanisms,andAI-poweredauditingtoolsthatsafeguardusersandtransactions.Therolecombineshands-onsoftwaredevelopment,threatdetection,incidentresponse,andsecurityautomationacrossdistributedsystems.Youwillhelpembedsecurityintotheproductlifecycle,ensuringthatprotectivemeasuresarereliable,measurable,andeasyforengineeringteamstoadopt.Workinginahighlytechnicalandcollaborativeenvironment,youwillhavetheopportunitytoinfluencesecurityarchitectureandstrengthentheresilienceofnext-generationblockchaininfrastructure. Accountabilities: Own wallet screening systems: Develop, operate, and improve services that screen blockchain wallet addresses before and during transactions. Optimize detection accuracy, caching, rescreening behavior, latency, and availability while integrating risk intelligence providers and external data sources. Strengthen transaction security: Define screening policies across transaction stages, blockchain networks, and wallet roles. Ensure that blocking decisions are explainable through clear error messages, auditable reports, and robust authorization and override mechanisms. Develop MEV and fraud detection capabilities: Build and operate near-real-time systems that identify sandwich attacks and other forms of maximal extractable value (MEV) targeting users. Measure detection precision and recall, maintain regression tests, investigate attack patterns, and collaborate with engineering teams to implement and validate mitigations. Maintain AI-powered security auditing tools: Own and enhance internal auditing systems that use large language models (LLMs) to identify vulnerabilities. Improve finding quality, reduce false positives, maintain regression datasets, and ensure findings are prioritized, assigned, and tracked through remediation. Build automated detection and response workflows: Develop monitoring and alerting systems to identify suspicious transactions, unexpected refunds, pricing discrepancies, and other financial anomalies. Automate daily loss reviews and create early-warning mechanisms to help prevent the movement of illicit funds. Lead incident investigations and continuous improvement: Participate in live security incidents, conduct investigations with security leadership, document timelines and findings, and translate lessons learned into new detection rules, automated checks, and preventive controls. Integrate security into product development: Partner with product and engineering teams to threat-model new features, review code for security risks, and implement reusable security components covering permissions, secrets management, audit trails, rate limiting, and abuse prevention. Operate production systems reliably: Build, deploy, instrument, and maintain security services, including logging, monitoring, alerting, and on-call support. Apply secure deployment practices, validate system behavior through testing, and maintain reliable operation of critical financial infrastructure. Leverage AI-assisted security engineering: Use and extend AI-powered tools to review code, investigate attack paths, automate analysis, and accelerate vulnerability triage while maintaining rigorous evaluation and quality controls. Maintain technical and compliance documentation: Record architectural decisions, incident reports, security findings, and remediation plans. Respond to partner and compliance requests related to screening coverage, blocked addresses, and security controls. Requirements Professional experience: At least 4 years of software engineering experience building, deploying, and operating production systems, with a strong interest in security engineering and experience supporting security-sensitive applications. Full-stack development: Strong TypeScript skills and the ability to work across backend services, databases, APIs, and internal user interfaces. Experience reviewing code and identifying potential security vulnerabilities is essential. Production operations: Demonstrated ability to own services throughout their lifecycle, including deployment, instrumentation, logging, monitoring, alerting, and incident response. Experience with containerized environments and Kubernetes is required. Distributed systems expertise: Strong understanding of queues, retries, idempotency, race conditions, concurrency, and numerical precision. Ability to design systems that remain correct when requests fail, responses are lost, or jobs execute more than once. Security and detection engineering: Experience building or operating fraud prevention, wallet screening, abuse detection, or similar security systems. Ability to evaluate performance against verified data using precision, recall, regression testing, and an understanding of false-positive and false-negative costs. Blockchain knowledge: Practical experience analyzing transactions on EVM-compatible blockchains, including transaction receipts, logs, block ordering, liquidity pool mechanics, and tracing funds or identifying wallet relationships. AI and automation: Experience operating LLM-based automation in production, including evaluation frameworks, regression testing, and disciplined management of prompts and detection rules. Smart contract understanding: Ability to read and assess Solidity code to determine whether automated vulnerability findings are valid and actionable. Secure architecture: Experience threat-modeling new features and conducting security reviews with product teams. Familiarity with identity and access management, secrets management, auditability, and the safe handling of operations that modify system state. Communication and collaboration: Strong written and verbal communication skills, including the ability to document incidents, explain technical risks, communicate with external partners, and translate security requirements into practical engineering improvements. Operational mindset: Comfortable participating in on-call rotations for financial infrastructure operating 24/7. Able to remain composed during incidents, investigate complex issues, and make evidence-based decisions. Additional assets: Experience with Rust, smart contract auditing, wallet security, MEV and mempool analysis, AML and sanctions screening, wallet-risk providers, blockchain indexers, or block-level tooling is advantageous. Experience in payments, cryptocurrency exchanges, or other high-stakes environments, as well as hands-on offensive security testing or purple-team exercises, is also valued. Benefits Competitive compensation: A competitive base salary aligned with experience and expertise. Equity participation: An equity package offering an opportunity to share in the long-term growth of the business. Comprehensive healthcare: Health benefits designed to support employee well-being. Flexible time off: An unlimited paid time off policy with an encouraged minimum to support regular rest and work-life balance. Remote-first work environment: The flexibility to work remotely, with a strong emphasis on collaboration, communication, and team connection. Professional growth: Opportunities to develop expertise across blockchain security, distributed systems, AI-powered security tooling, and emerging financial technologies. Meaningful technical ownership: The opportunity to own critical production systems, influence security practices, and directly contribute to protecting users and financial transactions.