REIN Security has emerged from stealth with $8 million in funding, backed by Glilot Capital, and is pitching an inside-out approach to application security (AppSec). According to SecurityWeek, the Tel Aviv and New York–headquartered startup was founded in 2024 by Matan Bar Efrat (CEO) and Netanel Rubin (CTO) to protect production applications from within while they run.
The company has developed a patent-pending platform that adds a single line of code to an application, baselines normal behaviour in less than a day, and then issues alerts or prevents deviations in real time. Rein claims runtime protection across both zero days and one days using production context with under one millisecond of performance impact and no reliance on proxies, sampling or eBPF.
The founders describe a non-intrusive approach that micro-sandboxes the exploited resource rather than terminating processes or HTTP requests. Written by Kevin Townsend, the piece positions Rein as addressing a visibility gap that existing AppSec tools, which focus on pre-production testing, do not cover.