F5 Inc., the Seattle-based application delivery and security company, is expanding its portfolio with today’s acquisition of CalypsoAI Inc., a leader in enterprise artificial intelligence security.

The acquired company was founded in 2018, showing it has been pioneers in the AI security market long before the latest hype cycle. The purchase price was announced at $180 million. The company had raised $43.2 million over three rounds, so the acquisition price provided the investors a strong return.

F5 plans to integrate privately held Calypso’s enterprise AI security capabilities — threat protection, AI data security, AI red teaming and observability solutions — into its Application Delivery and Security Platform, or ADSP, to add to its platform capabilities in securing AI systems and connected data across hybrid and multicloud environments.

I had the opportunity to talk about the announcement with John Maddison, F5’s chief product and corporate marketing officer, who said the acquisition will “establish F5 as a leading contender in the AI security space.”

Fourth F5 acquisition this year

CalypsoAI, which is based in Dublin, Ireland, is F5’s fourth acquisition in 2025. The company previously acquired MantisNet, which operates in the extended Berkeley Packet Filter or eBPF observability and real-time network intelligence market. It also bought Fletch, an agentic SOC threat intelligence company, and LeakSignal, which provides real-time data protection and governance for AI applications. Maddison cited the acquisitions as providing “new technologies and new people” to F5.

He said the decision to acquire CalypsoAI was the culmination of a deep dive into about two dozen AI providers with technologies and solutions that would complement F5’s internally developed AI gateway.

“CalypsoAI has a couple of key things,” Maddison said. “One, they have a red-teaming capability that uses swarms of agents to identify thousands of new attack patterns per month, which is a great tool for helping customers adapt to the ever-changing nature of AI. And then they had the best inference model protection.” He said that in head-to-head deployments against a leading security provider that emphasizes security of the training model, CalypsoAI “won out on the inference security because it’s very different to protect the inference model versus the training model.”

Maddison said F5 expects the transaction to close in a few weeks, which will enable F5 to introduce CalypsoAI’s capabilities quickly to current and prospective customers. “There are a lot of players in the market with slightly different variants, but we feel CalypsoAI has the best protection out there in large part because of its Red Team product, which is building perhaps the biggest AI CVE database out there,” he said. “It’s going to be a very dynamic marketplace, but we feel like we’ve got something we can sell out there straight away.”

Delivering proactive, continuous AI protection

The combination of F5’s application delivery and security solutions and CalypsoAI’s adaptive AI security capabilities will enable ADSP to deliver “proactive and continuous AI protection regardless of model or cloud,” including:

• Data security: Guardrails detect and prevent data leakage from sensitive disclosures and policy violations at runtime. Customers will be able to apply real-time protection for DLP and policy violations and audit AI interactions across models.

• Adversarial threat protection: Protect AI models and agents from threats such as prompt injections and jailbreak attacks with AI-augmented threat management and agentic intelligence. Proactive, automated red team vulnerability testing uses a swarm of agents to create more than 10,000 new attack prompts every month, leading to signature attack packs customers can use out of the box. Calypso also produces a model-specific risk scores via a leaderboard for how well the foundational models stack up against these risks.

• Unified visibility and governance: Centralized observability, policy control, and audit logs streamline GDPR/EU AI Act alignment across SaaS, on-premises and hybrid environments, and across commercial and open-source models — delivering a unified, scalable operating model for AI security.

Adding AI talent

In addition to CalypsoAI’s technology, Maddison said F5 is excited about the AI talent that will be joining F5. About two-thirds of CalypsoAI’s employees are engineers, something all fast-growing technology companies require. I’ve been told by many vendors that hiring AI talent is the hardest thing to do. With this acquisition, F5 gains complementary security technology to extend its portfolio and the expertise of the CalypsoAI team to bring the benefits of the combined company to more organizations around the world.

“F5 has locations in Seattle, San Jose, India and Ireland,” said Maddison. “With CalypsoAI adding significant AI talent to our Ireland presence, we believe will be able to tap into even more of the European skill set, as well.”

He is also looking forward to adding CalypsoAI’s Leaderboard to the F5 solution mix. The Leaderboard is a benchmark that ranks generative AI models according to their security, resilience, and performance. It uses the proprietary CalypsoAI Security Index and Agentic Warfare Resilience scores to deliver a transparent, data-driven view of AI model risk. The results enable chief information security officers and developers to make informed decisions about choosing and deploying AI in their production environments.

“I was speaking with our sales leads recently and they said customers and prospects want to understand what we are doing around AI security,” Maddison recalled. “The addition of CalypsoAI’s guardrails and vulnerability testing, as well as risk scores for all the foundational models gives us something we can empower customers with right away.”

For F5, the acquisition can help the company solidify itself as a security vendor. One of the tenets of my research is that there are market share gain opportunities when markets transition. Though F5 does have a strong set of security capabilities, including a web app firewall, distributed-denial-of-service protection, network firewall and more, few people think of the company as a security vendor. This is partially thanks to its strength as an application delivery company, but F5 has been working to change this perception.

AI presents a significant opportunity for F5 to use the CalypsoAI leaderboard to inform customers, driving mindshare but then bring solutions to bear to help secure AI initiatives. If it can execute on this transition to a mainstream security company, it will create another wave of growth for itself. The company currently has a market cap of about $20 billion from predominantly selling application delivery controllers. AI security has a much bigger market, and even a small piece would move the needle.

Zeus Kerravala is a principal analyst at ZK Research, a division of Kerravala Consulting. He wrote this article for SiliconANGLE.

Image: F5