Horizon3: Building the leading autonomous defense platform

Imagine if instead of waiting for thieves to rob your home, you could have a “reformed” thief proactively identify weak points where they could break in. That’s how Horizon3 is modernizing cybersecurity through AI-powered penetration testing. It helps organizations see their environment through the eyes of an attacker, continuously finding, fixing, and verifying exploitable security risks. 

Founded in 2019 in San Francisco by Snehal Antani and Tony Pillitiere, Horizon3’s mission is to be the industry's most trusted autonomous penetration testing platform. Snehal has over 25 years of experience in tech and cybersecurity, including working with Fortune 500 companies like IBM and General Electric, and he was CTO at Splunk before joining the U.S. Armed Forces' Joint Special Operations Command (JSOC.) When it comes to cybersecurity, Snehal has sat in all the major stakeholder seats—practitioner, vendor, government entity—giving him a unique perspective on this sector.

Horizon3 helps defend organizations like healthcare and educational institutions from crippling losses. Worldwide end-user spending on security and risk management is projected to total $215 billion in 2024, with the average data breach cost reaching $9.48 million in 2023.

The industry is spending too much on other security tools for there to still be such catastrophic and expensive breaches, underscoring the need for Horizon3’s preemptive solutions.

In this article we’ll cover:

• Unique insights into cybersecurity from Horizon3 founder Snehal Antani’s journey
• Tips for how security startups can manage and scale their companies
• How experienced security investors like SignalFire can help startups in the sector

How Snehal Antani redefined pen testing

Long before starting Horizon3, Snehal’s fascination with cybersecurity emerged from a mix of childhood curiosity and necessity.

Growing up, Snehal faced a predicament most kids of the 1990s suffered: his dad would restrict dial-up internet access as a penalty for unfinished homework. Rather than a roadblock, Snehal saw this as a challenge. Snehal soon discovered attacker tools hosted on various bulletin board services that helped him reclaim his digital freedom. The experience gave him a firsthand peek into cybersecurity—and its immense power and ethical implications.

Snehal’s mindset was crystallizing in those early days—he saw obstacles as opportunities for growth and experimented his way to new understanding.

From curious tinkerer to cybersecurity innovator 

“Are we actually protected?” was a common refrain Snehal heard while talking to cybersecurity tool customers. They had plenty of resources to buy the latest defenses but were never sure attackers couldn’t get in. From roles in hands-on technical support to the nuanced challenges of performance engineering, Snehal gained a comprehensive view of how different pieces of the security patchwork stitch together. When he later transitioned from an engineer to a CIO, he found himself buying the technology he once helped build, and being plagued with that age-old question. 

Snehal committed to immersing himself in the remaining pieces of the cybersecurity software life cycle. At Splunk, he ventured into sales and market engagement to learn what gave buyers confidence. “I knew how to build a product; I wanted to focus on being on the road and building out the selling skills.”*

When Snehal left Splunk at the end of 2017, his ambitions to fix the problems he’d faced throughout his career only grew, so he sought to grow his network of battle-tested developers. “Even though I was well-connected at Splunk, I wasn’t plugged into the engineering community deeply enough to rally an early team for my venture,” Snehal admits.

From 2018 to 2021, Snehal took on one of the most important roles in cybersecurity, working full-time as the first Chief Technology Officer for Joint Special Operations Command (JSOC) as part of the U.S. Department of Defense. That experience allowed Snehal to recruit retiring talent to form Horizon3’s founding engineering team, which is now a team made up of U.S. Special Ops, U.S. National Security, and cybersecurity veterans.

To finalize what they should build together, Snehal went looking for advice from those who could offer a different perspective.

One mentor advised Snehal to identify underserved sections of the industry. Snehal’s experience at IBM/GE gave him a clear target gap—despite buying the best security tools, organizations still weren’t secure—so he decided to zero in on security penetration testing, a niche dominated by mediocre services and ripe for disruption. “Pen testing was recession-proof, with a well-defined budget mostly fulfilled by consultants. It was the perfect target for innovation if I could automate the process,” he reflects.

Lessons along the way: Snehal Antani’s advice for entrepreneurs

Snehal is candid about how entrepreneurs can best navigate their partnerships and investor relations: 

1. Learn to prioritize for long-term success

“Amid tactical fires, it’s crucial to see the forest through the trees,” he emphasizes, highlighting the importance of maintaining a long-term vision amidst immediate challenges. 

A CEO’s job often involves creative problem-solving to unblock issues and move forward. But you need to take a systematic approach and avoid the temptation of short-term gains or fixes that might hurt your startup later.

2. You don’t have to do it alone

He stresses the value of tapping into seasoned professionals’ collective wisdom and experience. “Having open dialogues with trusted advisors helped me navigate complex issues, from personnel dilemmas to strategic pivots, without feeling judged for the inevitable mistakes along the journey.”

3. Come into the office as much as possible

Snehal also advocates for the power of in-person interactions, especially during the early days. “Coming into the office and engaging with people face to face fosters a sense of belonging and builds trust over time,” he notes. 

Modernizing cybersecurity with AI: SignalFire and Horizon3’s partnership 

At SignalFire, we had struggled with the same question Snehal asked himself as CIO—how could we be sure that the products we were investing in were actually improving cybersecurity posture? Our team was captivated by Horizon3’s potential to redefine cybersecurity norms by turning pen testing from a haphazard art to a precise science.

Snehal would describe his journey to finding the right VC as long and tedious, though. He’d had more than 50 VC meetings before connecting with SignalFire.

Snehal shared one of the tricks he used to find the right investor:

“In my pitch deck, there were 22 slides. The 22nd slide was an FAQ with five questions. I had intentionally put a weird claim in question three, halfway through. I was inspired by the green M&M ban musicians sometimes add to their contract. If they get to their dressing room and there are green M&Ms, they know you didn’t fully read the contract and do your due diligence.”

As soon as the meeting started, SignalFire asked Snehal about his dubious claims in the FAQ slide.

Snehal knew right then and there that we had put in the time and done our homework. He later explained, “You were by far the best prepared, and as a result, you had the highest conviction. You did your due diligence, and you were the obvious choice for us to go with. So two weeks later, we had a founder-friendly term sheet.”

A partnership from seed to scale

Snehal credits much of Horizon3's success to the invaluable insights and connections fostered by SignalFire. "Being introduced to SignalFire's user groups—from marketing to customer success—was a turning point for us," he says. "It went beyond networking, offering us a platform to exchange ideas, tackle challenges, and glean wisdom from those who've walked similar paths. This was especially valuable for my direct reports and functional leaders because they could be part of peer groups that openly discussed common challenges."

SignalFire’s role evolved as the company scaled, particularly in recruitment. Snehal reflects, “While we initially leaned heavily on our networks, bringing in talent through referrals, SignalFire’s structured recruiting process later played a crucial role. For instance, our VP of finance and other key positions were sourced through SignalFire’s platform [Beacon AI]. The candidates brought diverse strengths to the table, on top of just being impressive on paper.”

Snehal found that SignalFire's tailored support and shared expertise were pivotal in helping him navigate the complexities of scaling a tech venture.

How partnering with a VC can help through different startup phases

In the early days of our partnership, the focus was on helping Horizon3 fine-tune their product, determine the best sales approach, and bring the right people on board. Then came the curveball—the interest rate environment took a turn, and suddenly, it was all about survival. 

But instead of hitting the panic button, Horizon3 doubled down on what was working. The company managed to make it through the rough patch without letting go of a single team member. Snehal proudly points out that navigating these tough times together was a testament to their resilience and strategic thinking.

Choosing the right venture capital partner can dramatically alter a startup’s trajectory, not only by offering needed capital but also by embedding their expertise, network, and support into the very DNA of the company.

For founders aspiring to transform their industry, consider that the right partnership could be that one step that changes everything. SignalFire provides support across recruiting, HR, engineering, go-to-market, PR, fundraising, M&A, and more through our combination of AI technology and in-house experts. 

If you’re building a startup in cybersecurity or one of SignalFire’s other core sectors including healthcare and life sciences tech, developer tools, or enterprise SAAS, we’d love to learn more about you.

Get an intro to one of our partners.

Horizon3’s thoughts on partnership with VCs 

We asked Snehal to share his top four reasons for a CEO to work with VCs, and here are his thoughts:

1. Sharpening the edge

The right partner can provide invaluable insights into product positioning and engineering. This helps ensure your solution stands out and meets market needs effectively. In the competitive tech landscape, how your product is perceived can make all the difference.

2. Accelerating growth

Talking revenue and market strategies is a staple in venture partnerships. With SignalFire’s involvement, Horizon3 was able to refine its approach to sales and marketing, from outreach efforts to building prospective client lists, driving significant business growth.

3. Comprehensive support

Beyond funding, the support VC offers includes providing data, strategic advice, and the essential resources needed to scale. Seek out investors that complement your team so you have expertise in every critical function.

4. Weathering storms together

Perhaps most importantly, a true venture capital partner stands by you during the inevitable challenges. SignalFire demonstrated this to Horizon3 through open dialogues, tough love, and strategic pivots, helping Horizon3 navigate rough waters without losing course.

* Portfolio company founders have not received any direct compensation for this feedback. These founders may or may not serve as Affiliate Advisors, Retained Advisors, or consultants to provide their expertise on a formal or ad hoc basis. They are not employed by SignalFire and do not provide investment advisory services to clients on behalf of SignalFire. They may or may not have made a personal investment into a SignalFire fund.