Hey there, Cybersecurity Enthusiasts! ð¡️At Factorial, we're on the hunt for a skilled Application Security Engineer to join our Security Team. If you have a passion for ethical hacking and want to make an impact in a dynamic tech environment, we'd love to hear from you!ðAbout the team ðSecurity at Factorial works side by side with Product and Engineering to help a fast-moving, AI-native company ship without losing control of risk. Our mission is to protect Factorial and our customers while making security a practical part of how software is designed, built, tested, and operated.The work goes far beyond finding vulnerabilities: we test real product surfaces, help teams fix issues properly, and turn repeated security needs into guardrails, automation, and CI/CD controls that developers can use every day.

AI is part of Factorial’s culture, product, and way of working from day one, so Security also helps define how teams use agents, LLMs, tools, and company data safely at scale, while actively challenging those systems with an attacker mindset.It’s a team for people who want to keep learning, move across different security problems, and build security that can keep up with the speed of the company.Perform proactive penetration testing across Factorial’s applications, APIs, infrastructure, and AI-powered features.Collaborate with development teams to remediate security findings and enhance secure coding practices.Improve how we validate, triage, and remediate vulnerabilities from bug bounty reports, internal testing, automated controls, and external research.Hunt for recurring or legacy vulnerability patterns based on root cause analysis, previous incidents, and security findings.Build and improve security automations, agents, skills,



and CI/CD controls that help engineering teams catch and fix issues earlier.Help secure Factorial’s use of AI across product and internal workflows, including LLMs, agents, data access, tools, permissions, and abuse scenarios.Contribute to the development of our security tools, automations, and infrastructure.Stay up-to-date with the latest security research, threats, attack techniques, and emerging AI security risks. You have 3+ years of professional experience in Application Security, Offensive Security, or Penetration Testing.

Web Application Penetration

Testing experience is mandatory.You hold a degree in Engineering or Computer Science and have strong knowledge of web applications, databases, network protocols, and operating systems.You possess strong knowledge in cybersecurity fundamentals, CVSS, testing methodologies, and tooling.You are fluent with scripting or programming languages used in security testing and automation, such as Python or Bash.You are technical, curious, and comfortable moving across different security problems instead of specializing in only one area.You like to attack systems, but you also enjoy building tools, automations, guardrails, and practical solutions that make security scale.You have curiosity and willingness to learn about AI security topics such as LLM testing, prompt injection, agentic workflows, data exposure, tool permissions, RAG security, and secure AI adoption.Experience with Ruby / Ruby on Rails applications is highly regarded,



but not mandatory.Fluency in English is required.The salary range for this position is between 40.000 - 55.000 base + 7-10%variable based on performance payed quarterly + ESOP plan.That’s why our Engineering Team follows an office-first, adaptable approach.However, we also understand the importance of focus and flexibility, so we support remote work when it makes sense (20%), whether for deep work, personal needs, or just a change of scenery.This balance helps us stay agile, creative, and closely connected, while giving everyone the space to do their best work.Our Hiring ProcessIntro Call Chat with our Talent Partner about your journey and goals.Final Coffee Chat A relaxed conversation with our CTO & VP of Engineering to explore our vision, culture, and your growth.The whole process is remote, using videoconferencing tools!About Factorial ðAt Factorial, we’re building the leading AI Business Management Software for companies of all sizes. Our platform centralizes key workflows across HR, Finance, Talent, Operations, and IT, freeing teams from manual processes so they can focus on what really matters: leading, growing, and taking care of their people.We are one of Europe’s fastest-growing SaaS companies, proudly headquartered in Barcelona. If you're excited to shape the future of business management technology, we’d love to meet you.Our ValuesWe own it: We take responsibility for every project.

We're dedicated to learning something new every day and, above all, share it.Perks of being part of Factorial ðHigh growth, multicultural and friendly environmentAlan as private health insuranceHealthy life with Wellhub (Gyms, pools, outdoor classes)Save expenses with CobeeLanguage classesBreakfast in the office and organic fruitFood discounts with NoraPet FriendlyMuch more that we'll spill during the interview process!

📌 Cyber Defence Engineer (Barcelona)
🏢 Factorial Hr
📍 Barcelona