Rein Security
Also known as Rein
Israeli-American startup securing custom-built enterprise AI agents at runtime.
Founded by
- Matan Bar Efratco-founder and CEO
- Netanel Rubinco-founder and CTO
- Rein Security sells a platform for monitoring and controlling AI agents that companies build themselves.
- It runs as a sidecar beside the agent rather than as a gateway or proxy.
- It baselines normal agent behaviour and can block actions that deviate from it.
- It launched in January 2026 as an application security company and repositioned on enterprise agents by June 2026.
- It was founded by Unit 8200 alumni Matan Bar-Efrat and Netanel Rubin.
Why it matters. For security teams at companies running their own AI agents that touch payments, customer data or code. Rein argues gateway-based tools see prompts, not the actions agents take.
- Founded
- 20243
- Offices
- Tel Aviv and New York3
- Out of stealth
- 28 Jan 20264
- Seed round
- $8 million, led by Glilot Capital (announced January 2026)3
- Employees
- About 23 (January 2026)3
- Customers it names
- Lemonade, HiBob (January 2026)4
- Later named customer
- Dun & Bradstreet (June 2026)5
- Deployment
- Sidecar beside the agent; no proxy or gateway5
- TechCrunch Startup Battlefield 200
- Selected, cybersecurity category (2026)6
Reading to start with
The shading behind a date shows how recent it is: full within 3 months, empty after 2 years.
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8 months ago
Calcalist on the seed round, the investors and the founders' earlier companies.
-
3 months ago
Rein's announcement of its move to enterprise agent security and its Business Impact Analysis feature.
-
About Rein (opens reinsec.io)1
The founders' story and the list of angel investors.
Links
Sources
- About Rein: Solving Agentic AI Security (opens reinsec.io) read 2 Oct 2026
- Enterprise Agent Security Platform | Rein Security (opens reinsec.io) read 2 Oct 2026
- 8200 alumni raise $8 million Seed round for Rein Security as AppSec faces the AI era (Calcalist Ctech) (opens calcalistech.com) read 2 Oct 2026
- Introducing Rein Security: Bringing Production Context to Application Security (PR Newswire, via reinsec.io) (opens reinsec.io) read 2 Oct 2026
- Rein Enables the Next Wave of Enterprise AI Agents with Security Built for the Enterprise (opens reinsec.io) read 2 Oct 2026
- Rein Selected for TechCrunch's 2026 Startup Battlefield 200 (opens reinsec.io) read 2 Oct 2026
Last checked against its sources today
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