Senior Security Engineer - Fully Remote (Spain)

About this role

If you love getting hands-on with web security, cloud infrastructure and the emerging risks of AI and LLM integrations, you’ll feel right at home with us. At Metricool you will be able to do so with real ownership over how security and compliance get built into the product, not just audited after the fact. You will have the possibility to work 100% remotely, working in a high-growth international B2B SaaS, in which all members love to create, work in teams, analyze and help Community Managers make their work easier.

Your mission is to become the dedicated owner of application, cloud and AI security at Metricool, relieving our Senior Developers and Leads from manual security reviews and building specialized security management across our core monolith (JavaEE, Spring Security, Vue), AWS infrastructure, AI-powered features and internal compliance frameworks (ISO 27001, SOC 2). In this position, you will be able to make a wonderful contribution and impact in different areas: As Senior Security Engineer, Application & Platform Security: Harden Spring Security, JavaEE filters, CORS, anti-CSRF protections, SameSite/HttpOnly cookie flags, and strict CSP headers.

AI Security & Testing : Run threat modeling and vulnerability testing on our AI/LLM features, protecting against the OWASP Top 10 for LLMs: prompt injection, data poisoning, data leakage, insecure output handling, and API abuse. Compliance & Auditing (ISO 27001 / SOC 2): D efine, audit and collect technical evidence for compliance controls (access management, encryption at rest and in transit, incident logs), lead ISO 27001 and SOC 2 audits, and evaluate third-party vendor risk.

Infrastructure & Cloud Security: Configure AWS load balancers, Nginx, Tomcat, container security (Docker), and HTTPS enforcement. Code Reviews & Audits: Run regular code reviews, secret-detection audits, and third-party dependency reviews (Maven, Node.js). Build automated security checks (SAST/DAST/ZAP) into our CI/CD pipelines. As a Team Member: Cross-functional Alignment: Work closely with Senior Developers and Leads to bring security into the development process from the start, rather than bolting it on afterward.