Senior Software Engineer – OpenCTI

Department: Research & Development

Location: France

Employment Type: FullTime

🌀 The Company

Filigran, founded in October 2022, stands out in the cybertech ecosystem for its commitment to revolutionizing cyber threat management with a proactive approach. Its mission is to develop innovative open-source solutions designed to anticipate cyber threats, identify security gaps, and strengthen organizational security posture.

Filigran solutions are now trusted by over 6,000 public and private organizations worldwide.

🎯 The Role

We’re looking for a Senior Software Engineer to join the OpenCTI team and contribute to the core of our open-source platform. In this role, you will work on features and technical topics that are central to how users interact with and rely on OpenCTI, with a focus on product performances and stability.

You will bring strong technical expertise and have a direct impact on the product roadmap, collaborating closely with product, engineering, and community contributors. The role involves working across a modern stack including Node.js, TypeScript, React, GraphQL, and Elasticsearch.

💼 Your Responsibilities

• Contribute actively to the OpenCTI codebase, with strong ownership of new features and continuous improvements.

• Identify, investigate, and resolve bugs.

• Participate in technical brainstorming and task refinement, challenging both new proposals and existing implementations.

• Take part in the on-call rotation and act proactively during incidents to drive resolution.

• Mentor junior and mid-level engineers, supporting their technical growth.

• Address technical debt and legacy pain points.

• Lead or facilitate technical workgroups to explore and align on engineering topics.

• Review pull requests from internal teams and the open-source community

• Contribute to documentation and the shared knowledge base.

🤝 Who You’ll Work With

You will report directly to the Director of Engineering and work closely within a squad dedicated to our product Performances & Stability, alongside with a Senior Engineer, the Principal Engineer and the VP of Technology.

You will also collaborate regularly with the wider OpenCTI engineering organization, as well as with adjacent product teams such as Integrations, Platform, and Data.

🧬 Profile We’re Looking For

• 7+ years of experience as a Software Engineer, with solid exposure to complex, production-grade systems.

• Strong proficiency in a modern JavaScript/TypeScript stack, based on Node.js and GraphQL, and strong experience in technologies matching our backend stack (Elasticsearch, Redis, RabbitMQ).

• Comfortable working in a remote, async-first environment, with strong written communication skills.

• Proven ability to work autonomously, take ownership of technical topics, and drive initiatives from design to delivery with proactive reporting.

• A collaborative mindset, with a strong sense of team spirit and a willingness to mentor and support less experienced engineers.

• Ability to challenge existing solutions, address technical debt, and contribute to long-term architectural improvements.

• Experience contributing to or working with open-source projects is a strong plus.

• Bonus: Prior exposure to cybersecurity, threat intelligence, or large-scale data platforms.

🌱 Why Join Filigran? More than just a job.

We’re a fast-growing, global, and fully remote company building open-source cybersecurity solutions, increasingly powered by AI, to help defense teams anticipate threats and act faster.

⭐ What we believe

We believe we do work that matters, uniting defenders into a global community to make security more open, resilient & collaborative.

💻 How we work

We do work that matters by combining strong engineering standards with emerging technologies, including AI, to move faster and smarter.

🧭 What guides us

We make our work matter by building a culture grounded in our CORE values of Cohesion, Openness, Responsibility, and Equity. The principles that guide how we make decisions, treat people, and grow together, especially when no one’s watching.

💰 Compensation & Benefits

• Competitive pay + equity - everyone shares in our success

• Remote-first, flexible, and balanced - work that fits your life

• Your setup, your choice - pick the gear that works for you

• Twice-a-year gatherings - we meet in person for regional and global offsites to connect, collaborate, and strengthen our culture beyond the screen

🌍 Equal Employment Opportunity

We enable cybersecurity through inclusion - from code to culture.

At Filigran, we are proud to be an equal opportunity employer. We believe diversity of our people make our products and our team stronger. We welcome talent of every background, identity, and lived experience, regardless of race, color, religion, gender, gender identity or expression, sexual orientation, national origin, age, disability, or veteran status.

What matters here is what you bring, not what you look like, where you’re from, or how you identify.

🚀 Ready to Join Us?

Apply now and help us build the future of the cybersecurity ecosystem, together.