Principal AI Engineer

Our Engineering organisation is scaling its AI Engineering capabilities under new leadership, creating an opportunity to build the next generation of AI at Rapid7. We’re looking for Principal AI Engineers to join us and help shape what comes next by defining and influencing the technical direction of our LLM and agentic AI systems. As a Principal AI Engineer, you’ll raise the bar for engineering standards, and build truly cutting edge greenfield solutions that deliver real impact for our Global customers. Through your technical leadership and mentoring, you’ll help shape our product and platform investments and influence how we build and scale AI across the organisation.

About the Team

AI is reshaping cybersecurity on both sides. Attackers can use AI to strike at machine speed, and only AI-powered defense can keep up. At the same time, organizations can only adopt AI with confidence if it is secure. Rapid7 sits at the intersection of security and AI, and we are building industry-defining products for this new era.

Rapid7's AI Engineering team builds the AI that powers our security platform. We are AI engineers and applied scientists who take models from research to production, combining open-source and frontier LLMs, AI agents, and fast predictive models with more than 20 years of Rapid7 security expertise. Our work drives core use cases across Detection and Response, such as alert triage, threat investigation, and automated response, and Exposure and Remediation, such as vulnerability prioritization, attack surface risk assessment, and guided remediation. Together, these help customers stop threats faster and fix what matters most.

About the Role

As a Principal AI Engineer, you will set the technical direction for how Rapid7 builds, tunes and serves LLMs and agentic systems across its security products. You understand LLMs from the ground up, from transformer internals and training to fine-tuning and inference optimization, and you stay hands-on with the hardest problems. You know where LLMs shine and where they fall short, and you treat them as one tool in the AI toolbox, alongside predictive AI and classical ML, choosing the right approach for each problem. Specifically your focus will be to:

• Define the architecture and technical roadmap for LLM and agentic AI systems across Detection and Response and Exposure and Remediation
• Lead model strategy: when to use frontier or open-source models, and when to fine-tune, distill, or post-train
• Fine-tune, distill and post-train open-source LLMs on security data, from data curation through training, evaluation and deployment
• Set engineering standards for context engineering, inference optimization, and evaluation across teams
• Optimize LLM inference at scale with techniques such as speculative decoding, KV-cache management, continuous batching, quantization and custom kernels, balancing quality, latency and cost