Nightfall AI vs Prompt Security

Nightfall AI is a data loss prevention (DLP) platform that finds sensitive data in SaaS apps, email, endpoints, browsers and AI tools and stops it from leaking. It was founded in 2018 by Isaac Madan and Rohan Sathe, came out of stealth in November 2019 (it originally launched as Watchtower AI) and is based in San Francisco; its privacy policy names the operating company as Shoreline Labs, Inc. Sathe is now chief executive. Nightfall has disclosed $60.3 million in funding: $20.3 million at its 2019 launch, with the latest round co-led by Bain Capital Ventures and Venrock, and a $40 million Series B led by WestBridge Capital in August 2022. We found no later round and no acquisition. The product has five parts. Data Detection and Response scans SaaS apps through their APIs, including Slack, Google Drive, Gmail, Jira, Confluence, Salesforce, Microsoft 365, Notion and Zendesk. Data Exfiltration Prevention uses lightweight agents and browser plugins on macOS and Windows (Chrome, Firefox, Safari and Edge) to stop browser uploads, AI prompts, personal cloud sync, USB transfers and pushes to personal code repositories, and traces files from corporate origin to external destination. AI Security covers employee AI use (personal ChatGPT accounts, unmanaged copilots and browser AI tools) and AI agents, with hooks for Cursor, Claude Code and VS Code, MCP server discovery, and monitoring of Claude Enterprise through Anthropic's Compliance API. Data Discovery and Classification is an add-on that scans data at rest, and Nyx, launched in July 2025, is an AI agent that investigates incidents and tunes policies. In September 2026 Nightfall opened early access to an MCP Gateway that enforces policy on agent tool calls before they run. **AI compliance coverage** Nightfall's compliance material is about data protection frameworks, not AI regulation. Its help center explains how it helps with HIPAA, PCI DSS, SOC 2 and ISO 27001, and its detectors cover PII, PHI, payment card data, secrets and source code, with an out-of-the-box PCI detection template. We found no material on the EU AI Act, ISO 42001 or the NIST AI RMF. Its security page says Nightfall is SOC 2 Type 2 certified and that its databases are all in the United States. **Who it's for** Security teams that want one tool for SaaS DLP, endpoint exfiltration and employee and agent use of AI, particularly companies with sensitive data in Slack, Google Workspace and Microsoft 365. Its published customer stories include a health tech company using it to keep Slack and GitHub HIPAA compliant.

Prompt Security is an AI security product that controls how employees use AI tools and protects the AI applications and agents companies build. Itamar Golan (CEO) and Lior Drihem (CTO), who had worked at Check Point and Orca Security, founded it in August 2023; it is based in Tel Aviv. It raised $23 million: a $5 million seed round led by Hetz Ventures (January 2024) and an $18 million Series A led by Jump Capital (November 2024), with Ridge Ventures, Okta and F5 joining. SentinelOne, the Mountain View, California security company, agreed to buy Prompt Security on August 5, 2025 and completed the deal on September 5, 2025. Its Form 8-K puts the consideration at approximately $180 million in cash and SentinelOne Class A stock. Prompt Security is still sold under its own name, as part of SentinelOne's Singularity Platform. The product page is on sentinelone.com; prompt.security now hosts research and free tools such as the open-source Prompt Fuzzer, and the old press release we checked there redirects to SentinelOne. **What it does** SentinelOne's Prompt Security page lists three areas. AI Usage Control inventories the AI tools and code assistants employees and developers use, including unsanctioned shadow AI, and redacts sensitive data and enforces policies across more than 15,000 AI services in real time. It also covers GitHub Copilot, Cursor and Claude Code, keeping secrets and intellectual property out of them. AI Application Security tests homegrown AI apps for prompt injection, jailbreaks and data poisoning before deployment, runs a real-time AI firewall, and turns red-team findings into guardrails. Agentic AI Security finds shadow MCP servers and unsanctioned agents, enforces least-privilege access for agents and keeps a searchable audit log. SentinelOne says Prompt's MCP gateway scores the risk of more than 13,000 known MCP servers and can allow, block, filter or redact their actions. Prompt deploys through a lightweight agent and browser extensions, and covers major LLM providers, including OpenAI, Anthropic and Google, and self-hosted models. **Product changes since the acquisition** At its OneCon conference in November 2025 SentinelOne launched Prompt Security for Employees, for AI Code Assistants and for AI Applications, plus Prompt Security for Agentic AI in beta. At RSAC in March 2026 it announced Prompt AI Agent Security, a discovery and governance control plane for agents and MCP servers (agent posture management was in preview), and Prompt AI Red Teaming for testing homegrown AI apps. **Frameworks** Neither SentinelOne's Prompt Security pages nor prompt.security name the EU AI Act, ISO 42001 or the NIST AI RMF; they refer only to meeting compliance requirements in general terms. This profile lists no frameworks. **Who it's for** Companies that want to let employees use generative AI and coding assistants while controlling data exposure, especially existing SentinelOne customers. Named customers include 10x Banking and Carnival Corporation.