Doppel Buys PropRise, Adds Two Ex-Stripe Founders to Engineering Ranks

Doppel, the AI-powered cybersecurity firm defending against social engineering, has acquired Y Combinator-backed PropRise — a deal that lands two former Stripe engineers inside its security organization. Financial terms were not disclosed.

PropRise co-founders Jean-Michael Diei and Matthew Krager will join Doppel's engineering team to build out its autonomous threat detection and prevention capabilities. Doppel frames the deal primarily as a technology talent acquisition, not a product play.

Who are the founders joining Doppel?

Both men come from Stripe. In 2023 they founded PropRise, which built AI-powered software for the commercial real estate industry, serving institutional investors and real estate investment trusts (REITs). The startup grew to a high-six-figure annual recurring revenue run rate, according to Doppel, with AI applications targeting complex workflows in commercial real estate.

That revenue figure matters less than the credential it represents: two founders who have built and commercialized AI software end to end. "We've spent the last three years innovating at the frontier of agentic AI for commercial real estate, serving leading REITs and real estate investment firms," said Diei, Co-Founder and CEO of PropRise. "As cybersecurity threats grow increasingly complex, we see an enormous opportunity to bring that experience to a new generation of agentic defense solutions."

Why does Doppel want agentic AI talent?

Doppel develops AI-powered security technology that helps organizations detect and respond to impersonation, phishing, fraud and other social engineering attacks. Its Social Engineering Defense platform combines digital risk protection, human risk management and email security to identify threats across multiple channels and coordinate responses.

The platform already runs on automation. AI agents investigate suspicious activity, map attacker infrastructure and automate portions of the threat detection and disruption process. A shared Threat Graph connects intelligence across the platform's security products, so information identified in one area informs defenses elsewhere.

The timing is deliberate. Attackers are adopting AI tools to scale impersonation and phishing campaigns, which makes engineers who can build and deploy agentic AI applications an increasingly valuable asset in cybersecurity.

"We've built an engineering team that thrives on solving the world's hardest problems, and Jean-Michael and Matthew bring the exact kind of founder mentality and builder experience we want at Doppel," said Rahul Madduluri, Co-Founder and Chief Technology Officer of Doppel. "As AI transforms social engineering at breakneck speed, it's vital that we challenge assumptions, adapt quickly, and build what hasn't been built before."

Where does Doppel stand right now?

The acquisition caps a period of international growth. During 2026, Doppel expanded into Japan and Toronto, introduced additional capabilities across its Social Engineering Defense platform and surpassed 300 employees.

Its investor roster includes Bessemer Venture Partners and Andreessen Horowitz, plus strategic backers such as CrowdStrike CEO George Kurtz. The company was also named to Fast Company's 2026 Best Workplaces for Innovators list and the 2026–2027 Fortune Cyber 60 for the second consecutive year.

The deal signals where Doppel thinks the fight is heading: hiring founders who have shipped agentic AI commercially to out-build attackers using the same technology.