Horizon3 reaches $2 billion after fresh $250M funding round, riding automation surge in security

Horizon3 just raised a quarter billion dollars and hit a $2 billion valuation. That's not the surprising part. What matters is what the valuation jump means for how companies now think about defense.

The San Francisco startup closed its Series E in early August, more than doubling its valuation from last year's Series D round at $750 million. NEA led that earlier funding, which came in mid-2025 at $100 million. This time, the gap between rounds signals something harder to miss: enterprise buyers have stopped treating security as an annual event and started treating it as continuous.

From yearly checkups to always-on probing

Horizon3's NodeZero platform does one thing differently than the industry standard. Instead of hiring consultants once a year to run penetration tests, NodeZero runs them constantly. The AI-powered system probes defenses automatically, finds gaps, and validates whether security actually holds up under pressure. Between 150,000 and 170,000 autonomous tests have run across the platform so far. More than 3,000 organizations use it now.

The growth numbers tell you how fast this shift is happening. Annual recurring revenue jumped 137 percent year-over-year in the first half of 2025 alone. The company, founded in 2019 by former military and tech security specialists, has raised roughly $428 million total since launch.

This matters for crypto infrastructure especially. Smart contract audits have always worked like traditional pentesting. A protocol launches, maybe gets audited once more after a major upgrade, then assumes it's locked down. The industry treats security as a box to check before going live, not a continuous process running underneath everything.

Expanding beyond networks

Horizon3 just released NodeZero WebApp Pentesting on July 29, extending the automation deeper into attack surfaces. Web applications get hit constantly with different threat vectors, so continuous testing there catches what one-off audits miss entirely.

The shift reflects broader urgency. Money continues flowing toward AI-driven solutions across enterprise infrastructure, and security automation has become part of that wave. The gap between a $750 million valuation and $2 billion in under a year isn't just about growth. It's about the market recognizing that traditional security doesn't scale anymore.

This article is informational and should not be considered financial advice or investment guidance.