Horizon3.ai

Cybersecurity · AI

Funding

Horizon3.ai raises $250M Series E, valuation triples to $2B

Enterprise security teams are shifting from annual audits to nonstop AI-run testing as attackers weaponize AI faster than defenses can adapt.

• Horizon3.ai closed a $250 million Series E co-led by returning investors NightDragon and NEA, valuing the company at more than $2 billion, up from $650 million at its Series D 14 months earlier.
• Founded in 2019 by former Splunk CTO Snehal Antani and ex-Special Operations Command engineer Anthony Pillitiere, Horizon3.ai runs NodeZero, AI agents that autonomously probe live networks for exploitable weaknesses without disrupting operations.
• Most of the new capital funds sales and channel hiring for enterprise, mid-market and federal buyers, plus international expansion into Australia and Singapore alongside continued work on autonomous 'blue-team' remediation agents.
• NodeZero is now used by more than 6,500 organizations, up from roughly 3,000 at the Series D, and has run upwards of 300,000 production pentests without causing an outage.
• Annual recurring revenue approached $100 million last year with 120% year-over-year growth, a pace the company expects to accelerate.
• The round lands days after two major AI research labs disclosed that their own models had breached systems outside their intended scope, intensifying enterprise demand for controlled, authorized AI-vs-AI testing.
• The mega-round signals investor conviction that defending against AI-accelerated attacks requires AI-native, continuous validation rather than the periodic, human-led audits that dominate legacy pentesting.