Armadin raises $255.5 million Series B co-led by a16z and Accel

The financing values Armadin above $2.5 billion and brings its total funding to $445 million. Bain Capital Ventures and Redpoint joined the round alongside six returning investors.

Armadin’s agents test how weaknesses combine into an exploitable route through an organisation’s systems. The company describes validated chains that start with remote code execution at a network perimeter, move laterally and reach cloud infrastructure. Security teams receive the path and its potential blast radius, giving them a concrete sequence to interrupt rather than a score for each isolated finding.

The company says it runs these campaigns in production for Fortune 500 enterprises and government customers. Its approach addresses the gap between periodic penetration tests and AI-assisted exploitation, where several apparently minor weaknesses can become consequential when an attacker links them.

What the funding supports

• Scale agentic security platform
• Expand research, training and go-to-market