Senior Full Stack Engineer

About Mars Security Mars Security is an early-stage cybersecurity company building a new category of security technology, backed by deep hands-on experience from offensive security, threat intelligence, and security operations.

We're building a platform that lets security teams run continuous threat hunting and detection engineering across their existing stack. Most SOCs cannot tell you which active campaigns their environment would catch today. Mars closes that gap.

Founded by experienced operators, backed by world-class investors, and working with design partners across financial services, healthcare, pharma, and industrial security. We're building a team of people who thrive on ownership, ambiguity, and impact.

About The Role Mars Security is looking for a Senior Full Stack Engineer to join the Engineering team at a stage where your decisions stick. The platform is complex: security teams work with high-density data, multi-step workflows, and operational contexts where clarity and speed are not optional. You'll own features end to end, from data models and APIs to the interface, working directly with founders, product, and the research team to build something practitioners actually want to use.

If you've built SaaS platforms with serious data and UI complexity, and you'd rather own the whole stack than one side of it, this is your role.

What You'll Do

• Architect and build core product features from scratch, with real ownership over technical decisions across the stack
• Design and build the backend services, APIs, and data pipelines behind complex security workflows
• Work directly with product and design to turn security workflows into fast, usable product, from backend logic to UI
• Build reusable components and services, and set the bar for engineering quality across the team
• Own API design, performance, and integrations with the security tools customers already run
• Build LLM-powered and agentic capabilities into the product, from prompt and tool design to evaluation, guardrails, and production reliability
• Ship fast, iterate on feedback, and maintain high standards without bureaucracy

What We're Looking For

• 5+ years of full stack engineering experience, with a meaningful portion on SaaS platforms with complex, data-intensive products
• Strong across the whole stack: as comfortable designing a data model or a service as shipping the interface on top of it
• Hands-on experience running data-heavy systems, cloud infrastructure, and distributed services in production
• Strong product instincts across UX, reliability, and performance - you've worked on products where all three actually mattered
• Experience designing APIs, handling real-time data, and building systems that hold up at scale
• Hands-on experience building with LLMs in production (model APIs, RAG, tool calling, agent frameworks), and a clear view of where agentic workflows add value and where they break
• Capable of operating independently, making architectural decisions without constant guidance, and using AI tools to move faster without lowering the bar
• Startup experience is a strong advantage
• Based in Tel Aviv, on-site

Why Mars Security

• Ground-floor opportunity at a well-funded, fast-growing cybersecurity company
• Direct access to founders and real influence on product direction
• Deep exposure to a genuinely hard, unsolved problem in security
• Work on a product that security practitioners will open every day