Senior Security Engineer - xStocks

About the Role

BUILDING THE FUTURE OF OPEN FINANCE Payward - the parent company behind Kraken, NinjaTrader, Breakout, xStocks, Payward Services and CF Benchmarks - has spent the last 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. THE TEAM xStocks brings real-world assets on-chain as tokenized securities that are regulated, fully-backed, and tradable across multiple blockchains. Built within Payward, the xStocks team runs the infrastructure that issues, custodies, and settles these instruments across EVM, Solana, TON, Tron, and more. The platform moves real value, so security is not a feature bolted on at the end. It is a property of everything the team ships. This is a hybrid engineering and security seat built for someone who is genuinely both: you ship products alongside the engineering team when the security queue is quiet, and you own security work end to end when it lands. You report into engineering and partner closely with the Payward security, CISO, and compliance functions. THE OPPORTUNITY - Own security deliverables end to end. Coordinate and review smart-contract audits, respond to security questionnaires and due-diligence requests, support CISO and compliance initiatives, and turn findings into tracked, closed-out fixes. - Run offensive assessments against our own platforms. Pentest the web apps, APIs, backend services, and on-chain components, and build the tooling to do it repeatedly rather than once. - Continuously assess posture. Threat-model new and existing systems, review architecture and key-management flows, and maintain a living view of the risks and their mitigations. - Review code for security. Be a default reviewer on changes touching auth, cryptography, custody, signing, and fund movement across our chains. - Harden the platform. Improve secrets handling, IAM and least-privilege, dependency and supply-chain hygiene, and de

Key Responsibilities

• Own security deliverables end to end. Coordinate and review smart-contract audits, respond to security questionnaires and due-diligence requests, support CISO and compliance initiatives, and turn findings into tracked, closed-out fixes.
• Run offensive assessments against our own platforms. Pentest the web apps, APIs, backend services, and on-chain components, and build the tooling to do it repeatedly rather than once.
• Continuously assess posture. Threat-model new and existing systems, review architecture and key-management flows, and maintain a living view of the risks and their mitigations.
• Review code for security. Be a default reviewer on changes touching auth, cryptography, custody, signing, and fund movement across our chains.
• Harden the platform. Improve secrets handling, IAM and least-privilege, dependency and supply-chain hygiene, and de

Requirements & Qualifications

• Strong problem solving foundations, knowledge of modern engineering practices, and interest in technology systems.

Perks & Benefits

• Official mentor support
• verified hiring timeline
• and career progression.