Senior Security Engineer DeFi & AI Security

Remote | US & Canada | UK & EU – EST Hours Join a fast-growing fintech and blockchain technology company building secure financial infrastructure for the next generation of on-chain finance. We are looking for a Senior Security Engineer to partner with the Head of Security and help build, operate, and scale the company’s security program. You’ll work at the intersection of capital, risk, technology, and blockchain , securing systems that support sophisticated financial activity and high-value digital assets. You’ll own security initiatives across product, infrastructure, and operations , designing controls, automation, monitoring, and detection capabilities for highly adversarial environments. What You’ll Do Threat model new product features and integrations and strengthen systems with effective security controls. Operate and improve the application security toolchain while keeping it high-signal for engineering teams. Own day-to-day security operations across EDR, SIEM, on-chain monitoring, identity, and cloud security. Triage security alerts, investigate incidents, resolve vulnerabilities, and continuously reduce security noise. Assess vulnerability and bug-bounty findings based on actual exposure and drive remediation through completion. Support incident response activities from initial investigation through resolution. Lead security tooling and projects from evaluation and vendor selection through company-wide implementation. Collaborate closely with engineering, infrastructure, product, and other teams. Automate repetitive security workflows using AI, including vulnerability management, AppSec, access reviews, SOC 2 and audit evidence collection, vendor due diligence, and recurring security reporting. Build reusable AI components, Claude skills, and security agents that can be adopted by engineering and other teams. 5+ years of hands-on security engineering experience across product/application security and security operations. Strong track record conducting technical security assessments of software and systems. Experience with system hardening, security policy analysis, and implementing effective security controls. An adversarial mindset with the ability to think like an attacker and challenge assumptions. Proficiency in Python, TypeScript, or JavaScript . Experience working with Claude Code, Codex, or similar AI development tools . Hands-on experience applying AI/LLMs to security automation and building reusable tools adopted by engineering teams. Experience owning security projects end-to-end, from vendor evaluation and selection through organization-wide rollout. Experience securing high-value or high-throughput transaction systems . Excellent communication skills with the ability to explain technical security risks clearly and drive findings to closure. Bonus Points Experience in crypto, blockchain, DeFi, or on-chain security . Experience securing financial infrastructure or transaction-heavy platforms. Remote-first working environment. Work from anywhere in the US & Canada . UK & EU candidates must be able to work EST time-zone hours . Regular company retreats and opportunities for in-person collaboration. 100% employer-paid medical, dental, and vision premiums for employees. $1,000 work-from-home stipend . Monthly reimbursement for home internet, phone, and cellular data. Unlimited vacation. 12 weeks of fully paid parental leave . Fertility benefits. Opportunity for incentive compensation. Equity participation. Compensation Base Salary: $180,000 – $210,000 USD Performance-based bonus Equity