Senior Security Engineer - xStocks

As a Senior Security Engineer for xStocks at Kraken, you own security end to end for a platform that brings real-world assets on-chain as tokenized securities across EVM, Solana, TON, Tron, and more. You are both an engineer and a security specialist: you ship products alongside the engineering team when the security queue is quiet, and you own security work when it lands. You report into engineering and partner closely with Payward's security, CISO, and compliance functions.

What you'll do

• Own security deliverables end to end, including coordinating and reviewing smart-contract audits, responding to security questionnaires and due-diligence requests, supporting CISO and compliance initiatives, and tracking findings to closure.
• Run offensive assessments against the platform: pentest the web apps, APIs, backend services, and on-chain components, and build tooling to do it repeatedly.
• Continuously assess security posture through threat-modelling new and existing systems, reviewing architecture and key-management flows, and maintaining a living view of risks and mitigations.
• Review code for security as a default reviewer on changes touching auth, cryptography, custody, signing, and fund movement across chains.
• Harden the platform by improving secrets handling, IAM and least-privilege access, dependency and supply-chain hygiene, and detection and logging for security-relevant events.
• Secure custody and signing workflows by reviewing and hardening transaction signing flows, MPC and HSM integrations, signer permissions, admin roles, approval policies, and break-glass procedures.
• Contribute to product engineering by picking up regular backlog work in TypeScript to stay close to the codebase you are defending.
• Support incidents through detection, triage, response, and post-mortems, feeding lessons back into the security program.

What you bring

• Strong engineering fundamentals: you write and review production code comfortably in TypeScript and Node.js, and you understand systems deeply enough to break them.
• Strong application and infrastructure security fundamentals covering the OWASP vulnerability landscape, authn and authz, injection, SSRF, supply-chain risk, and secure design, with real offensive experience in pentesting, vuln research, or red-team work.
• Applied cryptography and blockchain security knowledge including symmetric and asymmetric primitives, hashing, signatures, key management, and the security model of EVM, Solana, and ideally TON or Tron; you can read a smart contract and reason about how it fails.
• Ownership: you can take an ambiguous security item, audit, questionnaire, or incident and drive it to closure without being managed through it.
• Clear communication: you can explain a risk to engineers, a CISO, and an auditor, tailoring the message to each audience.
• An automation instinct: you turn findings into tests, alerts, controls, documentation, or platform improvements rather than catching the same issue manually twice.
• Risk judgment: you can tell a theoretical issue from a material one and communicate severity, likelihood, impact, and remediation tradeoffs clearly.

Nice to have

• Experience commissioning or remediating third-party smart-contract audits.
• Familiarity with custody and signing infrastructure such as HSMs, MPC, and ForDefi-style providers, and with on-chain transaction security.
• Cloud security depth in GCP or AWS, IAM, and container and runtime hardening.
• Detection engineering and security observability experience, including SIEM and log-based detections.
• Relevant certifications such as OSCP, OSWE, or GWAPT.
• Prior work in a regulated fintech or tokenization/DeFi environment.

About Kraken

Kraken is part of Payward, which operates Kraken, NinjaTrader, Breakout, xStocks, Payward Services and CF Benchmarks. The group has spent 15 years building one of the most modern and globally accessible financial infrastructure platforms in the industry, built to advance an open, global financial system.