Senior Security Engineer – Open Finance & Blockchain

RWA Signal; Polska; Hybrid; PLN 180,000 - 300,000; Full time

Job summary

Payward is building the future of open finance. The xStocks team seeks an engineer with a security focus to own end-to-end security work across web, APIs, and on-chain components. You will join a hybrid engineering/security role reporting into engineering and aligning with CISO/compliance.

You will lead audits, perform pentests, model risks, review code for secure design, and harden platforms while collaborating with product teams.

Qualifications

• Experience delivering production-grade security in fintech/DeFi stacks.
• Strong knowledge of web and blockchain security fundamentals.
• Proven ability to own security work end-to-end.

Responsibilities

• Own security deliverables end to end; coordinate and review audits and due-diligence requests; support CISO and compliance; fix findings.
• Run offensive assessments; pentest web apps, APIs, backends, and on-chain components; build reusable tooling.
• Continuously assess posture; threat-model systems; review architectures and key-management flows.
• Review code for security; default reviewer on auth, cryptography, custody, signing, fund movement.
• Harden the platform; improve secrets handling, IAM, least-privilege, supply-chain hygiene and logging.
• Secure custody and signing workflows; review MPC/HSM integrations and break-glass procedures.
• Contribute to product engineering; backlog work in TypeScript to stay close to codebase.
• Support incidents; detection, triage, response and post-mortems.

Skills

TypeScript

Node.js

Security fundamentals

Cryptography

Threat modeling

Auditing

Ownership

Automation

Communication

Risk assessment

Job description

Payward is building the future of open finance. The xStocks team seeks an engineer with a security focus to own end-to-end security work across web, APIs, and on-chain components. You will join a hybrid engineering/security role reporting into engineering and aligning with CISO/compliance.

You will lead audits, perform pentests, model risks, review code for secure design, and harden platforms while collaborating with product teams.