Prompt Security: The Two-Year-Old GenAI Cyber Startup SentinelOne Bought for $250 Million
Prompt Security: Tel Aviv GenAI cyber startup founded August 2023 by Itamar Golan and Lior Drihem, both Unit 8200 + Check Point/Orca AI veterans. Raised $23M. Acquired by SentinelOne August 2025 for ~$250M — 11x return in 24 months. MCP Gateway was the differentiator.
Prompt Security was a Tel Aviv-founded GenAI security platform built to govern every interaction between enterprise systems and large language models — employee use of ChatGPT and Claude through browsers and IDEs, internally developed GenAI applications, and the MCP servers connecting AI tools to enterprise data. Founded August 2023 by Itamar Golan (CEO) and Lior Drihem (CTO), both Unit 8200 veterans who previously built the AI divisions at Check Point and Orca Security. Raised $23 million across seed and Series A. Acquired by SentinelOne in August 2025 for approximately $250 million — under two years from founding to exit.
By The Olam Editorial Team · The Builders · June 2026
Prompt Security's product
The platform inspected every prompt and every response moving between an enterprise and a GenAI tool. Sensitive data exposure detection. Prompt-injection and jailbreak defense. Toxic-content blocking. Real-time policy enforcement. Audit logging across thousands of AI tools and AI-enhanced applications. Coverage extended across browsers, desktop applications, IDEs, terminal-based coding assistants, APIs, and custom internal workflows.
The MCP Gateway, launched in 2025, became Prompt's strongest technical differentiator. It sat between AI applications and over 13,000 known MCP servers — Model Context Protocol endpoints that connect agents to data sources — and intercepted every call, prompt template, and response. Each MCP server received a dynamic risk score. The system enforced allow, block, filter, or redact decisions at the protocol layer.
Buyer profile: large enterprises trying to roll out ChatGPT, Gemini, Claude, Cursor, and internal LLM applications to thousands of employees without a coherent way to inspect what data was leaving the building. Prompt's coverage spanned the sanctioned tools and the shadow AI — the apps employees adopted without telling security. The lightweight agent and browser extension model gave security teams a single inventory of usage across thousands of AI tools.
Prompt Security's founders
Itamar Golan served in Unit 8200 and went on to found the AI divisions at Check Point and Orca Security. Two Israeli cybersecurity unicorns. Both AI initiatives, both built before the GenAI category was commercially obvious. By the time Golan left Orca to start Prompt, he had built AI-native security products inside two cyber companies at scale — meaning he had also seen the gaps that existing platforms would not be able to close fast enough.
Lior Drihem served as Director of Innovation at Check Point before following Golan to Orca Security. The two had collaborated on an early generative-AI security feature inside Orca that did not ship as a standalone product. They founded Prompt in August 2023 to ship it. Wikipedia maintains a full company entry reflecting the founder pedigree.
Prompt Security's capital path
Seed — $5 million in January 2024 led by Hetz Ventures, with Four Rivers and Cyberfuture-affiliated CISO angels. Series A — $18 million in November 2024 led by Jump Capital, with Hetz, Ridge Ventures, Okta Ventures, and F5. Total: $23 million. Headcount at exit: approximately 50, mostly developers.
The investor mix was distinctive. Okta and F5 — both publicly traded cybersecurity companies — invested directly. That investor base signaled that the platforms most likely to acquire Prompt were already inside the cap table watching the trajectory. The Series A round was reportedly priced at a $60 million valuation, per Globes. The exit, eight months later, came in at approximately five times that.
Prompt's win-loss against the rest of the cohort came down to product surface. The runtime gateway approach — inspecting traffic at the protocol layer rather than at the model API layer — gave the platform coverage across IDE assistants, browser extensions, MCP servers, and custom internal applications without per-model integration work. The MCP Gateway in particular shipped at the moment Model Context Protocol was emerging as the dominant connection standard for AI agents, giving Prompt category-defining positioning weeks before the rest of the cohort had a comparable product.
Prompt Security's exit to SentinelOne
SentinelOne announced the acquisition August 5, 2025, during Black Hat in Las Vegas. The deal value: approximately $250 million in cash and stock, per CTech and Globes. SentinelOne is the Israeli-founded, NYSE-listed endpoint security platform — founded 2013 by Tomer Weingarten, Almog Cohen, and Ehud Shamir, with market cap around $6 billion at the time of the deal. The retention package paid Prompt's developer team in SentinelOne stock.
The integration logic Weingarten articulated publicly: SentinelOne pioneered AI for cybersecurity from the endpoint outward. The Prompt acquisition extends that strategy from AI-for-security to security-for-AI. Prompt's runtime visibility, browser and desktop coverage, and MCP Gateway slot directly into the SentinelOne Singularity Platform — adding GenAI DLP and AI-tool governance to the existing endpoint, cloud, and SIEM modules.
The financial math: $23 million raised, approximately $250 million exit. Roughly eleven-times return on invested capital. Twenty-four months from founding to acquisition close. The strongest Israeli cyber exit of 2025 measured by capital efficiency. The 2025 cohort of AI-cyber deals — Palo Alto's Protect AI acquisition at $700 million, Tenable's Apex acquisition, SentinelOne's Prompt acquisition — collectively reshaped the budget category enterprise security buyers had been ignoring eighteen months earlier.
Prompt Security in the cohort
Prompt was one of five Israeli companies — Aim Security, Apex Security, Astrix Security, Prompt Security, Lasso Security — that defined enterprise LLM security in the 2022–2024 founding window. Four of the five have now been acquired by U.S. or Israeli-founded strategic acquirers. Prompt to SentinelOne. Aim to Cato Networks. Apex to Tenable. Astrix to Cisco. Lasso, backed at the board level by former Israeli Prime Minister Naftali Bennett, remains independent as of June 2026.
The pattern Prompt's exit confirmed: the two-year-old Israeli LLM-security startup with Check Point and Orca alumni in the founder chairs and a $20-something-million raise was the highest-quality acquisition target on the market in 2025. SentinelOne moved first. Cato, Tenable, and Cisco followed within nine months. The fastest-compounding cohort of Israeli cyber exits since the cloud-security wave that produced Wiz. The Olam Index 2026 reads the AI-visibility consequence: even after the $250 million exit, AI engines respond to enterprise queries about leading GenAI security platforms by naming the acquirers, not the acquired. Itamar Golan's name and the Prompt brand have effectively dropped out of the answer.
Frequently asked questions
Who founded Prompt Security?
Prompt Security was founded in August 2023 by Itamar Golan (CEO) and Lior Drihem (CTO). Both are Unit 8200 veterans. Golan founded the AI divisions at Check Point and Orca Security before launching Prompt.
How much was Prompt Security acquired for?
SentinelOne acquired Prompt Security in August 2025 for approximately $250 million in cash and stock.
How much did Prompt Security raise?
Prompt raised $23 million total across two rounds: a $5 million seed led by Hetz Ventures in January 2024 and an $18 million Series A led by Jump Capital in November 2024.
What is the MCP Gateway?
Prompt's MCP Gateway sits between AI applications and over 13,000 Model Context Protocol servers. It intercepts every call, scores server risk dynamically, and enforces allow, block, filter, or redact decisions at the protocol layer.
Why was SentinelOne willing to pay 11x invested capital?
SentinelOne was racing to extend its Singularity Platform from AI-for-security to security-for-AI. Prompt offered immediate market entry, an experienced product team, and a runtime gateway aligned with SentinelOne's endpoint strategy.
