Hackers are increasingly using AI to launch attacks on a massive scale, with email emerging as a primary target. AI can quickly aggregate personal information—such as information about coworkers, active projects, and recent travel itineraries—allowing bad actors to instantly craft convincing messages that look authentic.

Last year, former Google security executives Cy Khormaee and Ryan Luo, who previously worked on developing safe browsing technology and reCAPTCHA, teamed up to launch AegisAI, a startup that uses AI agents to stomp out these threats, known as spear phishing.

With a decade of experience preventing email hacks, the AegisAI co-founders realized that existing rule-based systems for preventing hacks—relying on “if-then” logic—are too slow and limited to catching AI-crafted malicious emails. So they developed AI agents that quickly analyze each message as a human would, paying attention to small anomalies that even the most elaborate checklist wouldn’t catch.

Less than a year after its launch, AegisAI says its tech has been adopted by dozens of customers, including crypto payments company Mash, AI startup LangChain, and Google-owned privacy compliance platform Lokker. That demand has just helped AegisAI raise a $36 million Series A led by Battery Ventures, with participation from existing backers Accel and Foundation Capital. The fresh funding brings the startup’s total capital to $49 million.

“AI-powered attacks bypass existing controls more than half the time now, which means they’re almost twice as effective as they used to be,” Khormaee told TechCrunch. “They’ve researched you, they understand everything about you, and they’re targeting attacks that are perfectly bespoke to you.”

Khormaee claims that AegisAI’s agents can spot threats traditional email security systems may miss entirely. For instance, the startup’s AI can catch malicious PDF attachments that look legitimate at first, including ones with built-in passwords and CAPTCHAs, which are often used to fool standard spam filters.

When Dharmesh Thakker, general partner at Battery Ventures, noticed an increase in email attacks, he set out to invest in a startup that could defend against AI with AI, one aiming to replace legacy email security tools with agentic-driven defense.

“The bad guys are using email to attack us using AI at a much faster pace than we can keep up with,” Thakker told TechCrunch. “Defending against that is going to be a number one priority for a lot of companies.”

AegisAI isn’t the only startup using AI to analyze the context of every incoming email to detect fraud and impersonation attempts. Lightspeed-backed Ocean is also trying to displace established vendors like Proofpoint and Mimecast, along with newer players like Abnormal Security.

However, given that AegisAI is led by experts who helped secure Gmail, the most popular email system in the world, Thakker believes the startup has the best shot at becoming the leading new hack-prevention company.

While AegisAI is starting with email, the startup has its sights on eventually expanding to other areas of defense, such as data security. “The core idea of building customized, highly advanced agents that can do investigations is going to [determine] who becomes the next dominant security company,” Khormaee said.