Rein Security Rein provides a runtime security platform for enterprise AI agents: it traces every agent action, holds each agent to its defined role, blocks harmful actions before they execute and prioritizes exploitable issues with generated fixes, without routing data through a gateway or proxy. Customers include Lemonade and Dun & Bradstreet. Founded in 2024 by Matan Bar-Efrat (CEO) and Netanel Rubin (CTO), Rein raised a $25M Series A in October 2026 co-led by Glilot Capital and Sienna Venture Capital, bringing total funding to $35M. It has offices in Tel Aviv and New York.