Employee AI-usage monitoring platform Harmonic Security closes $50M Series B on October 15

Harmonic Security, based in San Francisco and London, announced on October 15 a $50 million Series B led by Crosspoint Capital Partners with new and existing investors participating. The company's core product uses custom small language models to evaluate every employee-AI-tool exchange in milliseconds and applies real-time controls to block risky content; it now protects millions of employees at more than 100 companies. Harmonic also integrated with Claude's Compliance API so enterprise security teams can read Claude Platform activity logs in real time, covering four risk categories: prompt injection, unauthorised operations, data leakage and network abuse. Harmonic said the new capital will expand its engineering and sales teams and accelerate deployments across Europe and Asia Pacific.