Key Takeaways
- • Rein Security raised $25 million in a Series A round, lifting its total funding to $35 million, co-led by Glilot Capital and Sienna Venture Capital with participation from Corner Ventures, Atlacle and RNP Capital Advisors.
- • Founded in 2024 by Matan Bar-Efrat and Netanel Rubin, the Tel Aviv and New York-based company employs 31 people and is already generating sales.
- • Rein's platform uses patented "sidecar" technology to monitor AI agents at runtime, providing visibility into agent code and resource access, governance over agent activity, and real-time guardrails that block harmful actions.
- • Rein differentiates itself by focusing on AI agents built internally by organizations, operating inside the customer's cloud environment without routing data through a gateway or proxy, rather than only agents developed externally.
- • The round reflects growing enterprise concern that AI agents with broad access to business systems, data and workflows create security risks that traditional tools were not designed to detect or prevent.
Summary
Rein Security has raised $25 million in a Series A funding round, bringing its total funding to $35 million, according to CTech by Calcalist. The round was co-led by Glilot Capital and Sienna Venture Capital, with participation from Corner Ventures, Atlacle and RNP Capital Advisors. The company was founded in 2024 by Matan Bar-Efrat and Netanel Rubin and employs 31 people across offices in Tel Aviv and New York. According to Rein, the company is already generating sales.
The funding reflects a broader challenge facing enterprises. Organizations are rapidly deploying AI agents with increasingly broad access to business systems, data and workflows, creating security risks that traditional approaches were not designed to detect or prevent. Companies must now secure the AI agents they build while also defending against increasingly sophisticated attacks powered by AI. Rein's platform is designed to address both sides of this challenge. Its patented "sidecar" technology operates at runtime, when agents are executing actions, giving security teams visibility into every line of code an agent runs and every resource it accesses. The platform also provides governance over agent activity and real-time guardrails designed to block harmful actions. According to a company statement cited in publisher coverage, the technology detected and blocked an action before any damage occurred. The platform secures the AI agent supply chain without routing company or customer data through a gateway or proxy.
In a conversation with Calcalist, co-founder Netanel Rubin said that while many companies focus on securing agents developed outside their organizations, Rein concentrates on agents built internally. "We operate within the customer's cloud environment using a completely different technology," Rubin said. He added that every organization faces two AI-related challenges: agents developed independently on individual computers and those developed by the organization itself.
Coverage from other outlets describes Rein as an AI-native runtime security platform and says the new capital will be used to accelerate product development, expand AI security research and support global hiring.
The funding reflects a broader challenge facing enterprises. Organizations are rapidly deploying AI agents with increasingly broad access to business systems, data and workflows, creating security risks that traditional approaches were not designed to detect or prevent. Companies must now secure the AI agents they build while also defending against increasingly sophisticated attacks powered by AI. Rein's platform is designed to address both sides of this challenge. Its patented "sidecar" technology operates at runtime, when agents are executing actions, giving security teams visibility into every line of code an agent runs and every resource it accesses. The platform also provides governance over agent activity and real-time guardrails designed to block harmful actions. According to a company statement cited in publisher coverage, the technology detected and blocked an action before any damage occurred. The platform secures the AI agent supply chain without routing company or customer data through a gateway or proxy.
In a conversation with Calcalist, co-founder Netanel Rubin said that while many companies focus on securing agents developed outside their organizations, Rein concentrates on agents built internally. "We operate within the customer's cloud environment using a completely different technology," Rubin said. He added that every organization faces two AI-related challenges: agents developed independently on individual computers and those developed by the organization itself.
Coverage from other outlets describes Rein as an AI-native runtime security platform and says the new capital will be used to accelerate product development, expand AI security research and support global hiring.
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