Application security startup Rein Security Inc. formally launched today with a promise to address critical blind spots in application and artificial intelligence security.

Founded by industry veterans and backed by investors including Glilot Capital Partners LP, Rein offers technology that provides real-time context and protection inside application production environments.

Rein is seeking to assist with the issue where organizations are forced to contend with the growth of application programming interfaces, artificial intelligence-generated code and applications and the Model Context Protocol as the application security landscape rapidly changes and yet most struggle to see how their applications behave in production.

That problem and years of being forced to make decisions with incomplete data and time-consuming investigations are what led Rein co-founders Matan Bar Efrat and Netanel Rubin to start the company and build a platform grounded entirely in real production insight.

“Security teams have been forced to play guesswork for far too long and we can no longer allow application security to be rooted in assumptions instead of reality,” explains co-founder and Chief Executive Bar Efrat. “We founded Rein to give chief information security officers and AppSec leaders the ability to protect every app, MCP, library and API without disruption. By seeing and controlling exactly what happens to apps in production, teams can resolve real issues quickly rather than spending excessive time on investigations and analysis.”

The Rein platform solves key AppSec use cases, including API security and Software Composition Analysis reachability, by applying application runtime context to surface validated risks in production versus theoretical ones. The approach assists teams to move beyond static assumptions to understanding which APIs and libraries are present in applications in production, determine vulnerability reachability and focus remediation efforts more effectively.

Key capabilities of the Rein platform include complete visibility in production, runtime protection, AI security, agentless architecture and cross-domain application security support.

Though formally launching only today, Rein already has a customer base that includes companies in financial and other business-critical services. Notable customers include Lemonade Inc. and HiBob Ltd.

“Uptime and security are strict requirements. That’s why we need a way to understand what’s really happening in our apps, without relying on limited data, proxies or guesses,” said Jonathan Jaffe, chief information security officer at Lemonade. “Rein provides exactly that. Its granular baselines and real production visibility give us confidence that when something deviates, it’s real — not another false signal.”

Image: Rein Security