A San Francisco company called Horizon3, which builds software that automatically hunts for security weaknesses in computer networks, has raised $250 million from investors at a $2 billion valuation. Returning backers NightDragon and NEA funded the round. The new valuation is more than three times what the company was worth just 14 months ago, when it raised $100 million at a valuation above $750 million. TechCrunch

Horizon3's main product is called NodeZero. It works like a safe burglar testing your home while you are still living in it — checking every door, window, and weak spot without breaking anything or forcing you to leave. The company calls its automated system "AI Hackers," and unlike traditional security checks, which are done by humans a few times a year and cover only about 2-3% of a network, NodeZero runs continuously across an organization's entire infrastructure. TechCrunch

Horizon3 spent six years building the AI behind NodeZero, investing roughly $100 million in research to make sure the tool finds problems without causing any. The company says it has run 310,000 security tests on live customer systems with zero disruptions. Chief Revenue Officer Matt Hartley will lead the market expansion funded by the new capital. TechCrunch

On the financial side, Horizon3 approached $100 million in annual recurring revenue last year, growing 120% year-over-year. The company had previously raised $178.5 million in total funding across earlier rounds. Horizon3

Founders Snehal Antani and Anthony Pelletier met while serving at Joint Special Operations Command, a military background that shaped the company's focus on offensive security. Horizon3 is now expanding internationally, with an Amsterdam office opened in June 2026 and additional operations in Australia and Singapore. TechCrunch

The jump from a $750 million valuation in mid-2025 to $2 billion in August 2026 places Horizon3 among the faster-growing cybersecurity companies in the current cycle. The 120% revenue growth rate gives investors a revenue multiple in the low-to-mid twenties, which is high by normal software standards but consistent with what AI-focused security companies have been commanding lately.

The metric that sets Horizon3 apart is the 310,000 production tests run without a single disruption. For security teams in hospitals, banks, or other settings where systems cannot go down, a testing tool that accidentally crashes a live network is a serious problem. The company's $100 million research investment appears to have gone mainly into this safety boundary — making the automated hacking controllable enough to run on live infrastructure without causing outages.

The shift from occasional manual security checks to continuous, full-network coverage is not unique to Horizon3, but the company's track record gives it credibility that newer competitors will find hard to match. Traditional security testing has always had a coverage gap: a human team checking 2-3% of a network once a year gives a snapshot, not ongoing protection. NodeZero's continuous model addresses that directly, and the adoption numbers suggest organizations are willing to pay for it.

The international expansion is worth watching. Amsterdam, Australia, and Singapore are each hubs for financial services, critical infrastructure, or government defense work. Those are the three sectors most likely to buy autonomous security tools and most able to afford enterprise pricing. The Amsterdam office opening in June 2026 suggests the European push is already underway, with the new capital providing funding to staff up before competitors arrive.

The broader question is whether the $2 billion valuation holds up. A tripling in 14 months reflects investor confidence in both the company's performance and the rising threat of AI-driven attacks. If revenue growth continues even at half the current pace, the valuation should look reasonable. If growth slows to typical software-industry rates, the next funding round will test whether investors keep paying a premium for AI security tools.

For now, Horizon3 has capital, momentum, and a product that solves a problem security teams feel every day. The next 12 months will show whether continuous automated security testing becomes a standard part of enterprise security budgets or stays a specialized tool for the most advanced organizations.