CISO Tribune

Vendor comparison · 2 companies

Onyx Security vs Prompt Security

Onyx Security sells a secure control plane for AI agents and models. Prompt Security offers protection for both employee use of AI tools and the apps an organization builds. CISO Tribune files both under AI model and agent security and Workforce AI usage security. This page sets the two records side by side: what each sells, where it is based, who owns and funds it, the customers it names and its recent news, each fact numbered to its source.

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  • Onyx Security
  • Prompt Security
Onyx Security vs Prompt Security: Products, Customers and Funding Compared
Onyx SecurityOnyx Security sells a secure control plane for AI agents and models.onyx.securityPrompt SecurityPrompt Security offers protection for both employee use of AI tools and the apps an organization builds.prompt.security
What it sells
  • AI Security[1][7]Onyx provides the runtime and posture layer of the Onyx Secure AI Control Plane.
  • MCP Gateway[8]The MCP Gateway governs the agent-to-tool surface.
  • Prompt Fuzzer[4]An open source tool for AI vulnerability assessment.
Categories
Headquarters
Not stated on its pagesNot stated on its pages
Founded
Not stated on its pages2023[1]
Ownership and funding
Not stated on its pagesOwned by SentinelOne since 2025[3][7][8][10]
Named customers
Not stated on its pagesNot stated on its pages
Recent news
  • July 29, 2026Onyx Security announced a $113 million Series B funding round led by Bessemer Venture Partners.[15]
  • March 12, 2026Onyx Security officially launched operations after securing $40 million in initial funding.[14]
Not stated on its pages
G2 and Gartner Peer Insights
  • G2: Not stated on its pages
  • Gartner Peer Insights: Not stated on its pages
  • G2: listed, seen November 10, 2026[10]
  • Gartner Peer Insights: Not stated on its pages
Who it fits
From its own pages, Onyx Security sells mainly to security, governance, and AI teams that need control over AI agent adoption across the enterprise. Onyx Security describes a single platform for security, governance, and infrastructure teams. Onyx Security offers cloud, hybrid, or self-hosted options for organisations with sensitive data residency requirements. Onyx Security presents one console for AI agents and models across SaaS, cloud, endpoint, and code environments. Onyx Security names security, finance, and platform teams as the teams that share its usage, cost, and policy ledger.Not written yet
Last verified
October 19, 2026September 27, 2026

Where they overlap

  • Onyx Security and Prompt Security are both filed under AI model and agent security and Workforce AI usage security.

Where they differ, field by field

  • Onyx Security's primary category is AI model and agent security; Prompt Security's is AI firewalls and guardrails.
  • Onyx Security is also filed under AI governance and Non-human identity security.
  • Onyx Security lists AI Security and MCP Gateway. Prompt Security lists Prompt Fuzzer.
  • Prompt Security was founded in 2023.
  • Prompt Security is owned by SentinelOne, since 2025.

What it sells: Onyx Security

What AI Security does[1][7]
Onyx provides the runtime and posture layer of the Onyx Secure AI Control Plane. Onyx inspects every prompt, tool call, and model response inline across browser AI, coding assistants, desktop AI agents, cloud workloads, and MCP servers. Onyx offers five enforcement actions: alert, block, mask, steer, or ask.
What MCP Gateway does[8]
The MCP Gateway governs the agent-to-tool surface. Every tool call an agent makes to an MCP server gets inspected and policy-enforced. MCP Gateway coverage spans the MCP ecosystem, including servers using dynamic client registration and popular servers like GitHub.

What it sells: Prompt Security

What Prompt Fuzzer does[4]
Prompt Fuzzer is listed under AI Security Tools on the Prompt Security site. The site describes it as an open source tool for AI vulnerability assessment.

Questions about Onyx Security and Prompt Security

What do Onyx Security and Prompt Security sell?
Onyx Security sells AI Security and MCP Gateway. Prompt Security sells Prompt Fuzzer.
Are Onyx Security and Prompt Security in the same category?
They share AI model and agent security and Workforce AI usage security. Onyx Security's primary category is AI model and agent security and Prompt Security's is AI firewalls and guardrails.
When were Onyx Security and Prompt Security founded?
Prompt Security was founded in 2023.
Who owns Onyx Security and Prompt Security?
Prompt Security is owned by SentinelOne, since 2025.
Who are Onyx Security and Prompt Security sold to?
From its own pages, Onyx Security sells mainly to security, governance, and AI teams that need control over AI agent adoption across the enterprise.
What have Onyx Security and Prompt Security announced recently?
July 29, 2026: Onyx Security announced a $113 million Series B funding round led by Bessemer Venture Partners.

About Onyx Security

Onyx Security sells a secure control plane for AI agents and models. Onyx gives security, governance, and AI teams control to protect, optimize, and measure AI agent adoption across the enterprise. Onyx was founded around a single goal: to control the most advanced forms of AI. Onyx describes its secure AI control plane as a single platform that serves security, governance, and infrastructure teams as they oversee how AI agents are used, ensure they are secure and compliant, and measure their effectiveness.[1][2]

Onyx says enterprises were deploying autonomous agents faster than they could see, govern, or control them. Onyx offers one console for every AI agent and model across SaaS, cloud, endpoint, and code. Onyx discovers sanctioned and shadow AI across the enterprise, with visibility into every prompt, response, and agent action. Onyx identifies every agent, MCP server, AI tool, copilot, and embedded AI surface continuously, across SaaS, cloud, endpoints, and code. Onyx combines directory scanning, native platform APIs, and behavioral signature learning for browser-based AI to keep the inventory current. Onyx records every prompt, model response, and tool call by name, argument, and result, with the reasoning context preserved across turns. Onyx correlates agent activity to the invoking user and the agent owner, and captures the identity used on each tool and MCP call. Onyx forwards alerts and their session records to Splunk and CrowdStrike NG-SIEM.[1][2][4][5][8]

Onyx provides the runtime and posture layer of the Onyx Secure AI Control Plane. Onyx inspects every prompt, tool call, and model response inline across browser AI, coding assistants, desktop AI agents, cloud workloads, and MCP servers. Onyx applies five enforcement actions: alert, block, mask, steer, or ask (human in-the-loop). Onyx evaluates every agent on deployment and continuously across its lifecycle. Onyx red teaming continuously attacks deployed agents, generating attack plans across reconnaissance, jailbreaking, and weaponization. Onyx identifies supply chain risks in agents, MCP servers, models, and AI assets.[4][6]

Onyx gives an agent its own identity, separate from the invoker, when multiple users delegate to the same agent across tools. Onyx lets teams sanction approved tools and control MCP server access. Onyx offers pre-populated policy templates aligned to industry regulations. Onyx helps teams meet security standards from MITRE, NIST, OWASP, and more.[4][7]

Onyx centralizes all AI traffic on a fully-managed, OSS AI gateway. Onyx routes across popular LLMs to automate failover, minimize latency, and balance load by task complexity and cost constraints. Onyx proxies all MCP traffic with an inline gateway, logs every request and response, and enforces guardrails. Onyx evaluates every tool call an agent makes to an MCP server against scope, identity, data class, and policy before the call lands.[4][8]

Onyx lets teams define AI adoption targets by department, use case, or tool category. Onyx shows total AI spend, avoidable costs, and optimization opportunities. Onyx correlates AI usage, cost, risk, and outcomes to the same activity record. The Onyx AI Gateway captures per-request cost metadata at runtime: cost, tokens, model, and identity context. The Onyx Guardian Agent is a supervisory AI that continuously works across the platform to identify risks and remediate issues.[2][4][9]

Onyx offers cloud, hybrid, or self-hosted options for sensitive data residency requirements. Onyx supports deployment with AWS VPC, Bedrock Gateway, and custom proxy configurations. Onyx offers 100+ pre-built integrations that connect to agent platforms, frontier model providers, SIEM, and cloud platforms. Onyx pulls identity context from Okta and Microsoft Entra, and endpoint management context from Intune, Jamf, and Tanium. Onyx integrates with Claude Enterprise through the Compliance API, pulling conversation content, uploaded files, project data, and activity logs into the Onyx control plane. Onyx integrates with the OpenAI Compliance API, ingesting ChatGPT Enterprise workspace activity. Onyx integrates with Amazon Bedrock Agents through Bedrock Agent configuration APIs, agent invocation logs delivered to S3, and CloudTrail data events. Onyx integrates with Microsoft Copilot Studio through the Microsoft Graph API. Onyx Security is SOC 2 Type II and ISO 27001 certified.[1][4][6][7][8][10][11][12][13]

Onyx Security on the record

Sources

Onyx Security full record

  1. [1]onyx.securityOnyx Security · onyx.security · undated page, accessed October 19, 2026 · Tier A
  2. [2]The Secure AI Control Plane for the Agentic Era | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  3. [3]About Onyx | The Team Behind the AI Control PlaneOnyx Security · undated page, accessed November 10, 2026 · Tier A
  4. [4]One Platform to Discover and Control Every AI Agent | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  5. [5]AI Observability – Discover Every Agent & Session | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  6. [6]AI Agent Security | Block Prompt Injection in Real TimeOnyx Security · undated page, accessed November 10, 2026 · Tier A
  7. [7]AI Governance Platform Built for the EU AI Act | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  8. [8]AI Orchestration – Governed Routing & Control | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  9. [9]AI ROI Platform – Prove Value & Control Costs | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  10. [10]Secure Claude Enterprise with Onyx | Anthropic IntegrationOnyx Security · undated page, accessed November 10, 2026 · Tier A
  11. [11]Secure ChatGPT Enterprise with Onyx | OpenAI IntegrationOnyx Security · undated page, accessed November 10, 2026 · Tier A
  12. [12]Secure Amazon Bedrock Agents | Onyx IntegrationOnyx Security · undated page, accessed November 10, 2026 · Tier A
  13. [13]Copilot Studio Security – Discover, Govern & Control | OnyxOnyx Security · undated page, accessed November 10, 2026 · Tier A
  14. [14]Israeli cyber firm Onyx Security launches operations with $40 million funding round | ReutersReuters · published March 12, 2026 · Tier B
  15. [15]Onyx Security Raises $113M Series B to Control Advanced AI, Quadrupling Revenue since Stealth Launch Four Months AgoBusiness Wire · published July 29, 2026 · Tier A

Prompt Security full record

  1. [1]Prompt security partners with f5 to secure genai applications with a firewall for ai 302131373Prompt Security via PR Newswire · prnewswire.com · published April 30, 2024 · Tier A
  2. [2]Securing ai promptSentinelOne · sentinelone.com · undated page, accessed September 27, 2026 · Tier A
  3. [3]Sentinelone completes acquisition of prompt securitySentinelOne via The Globe and Mail · theglobeandmail.com · published September 5, 2025 · Tier A
  4. [4]Prompt Security | From SentinelOnePrompt Security · undated page, accessed October 27, 2026 · Tier A
  5. [5]AI Security | AI Glossary | Prompt SecurityPrompt Security · undated page, accessed October 27, 2026 · Tier A
  6. [6]ClawSec: A Security Skill Suite for OpenClaw AgentsPrompt Security · undated page, accessed October 27, 2026 · Tier A
  7. [7]AI Security Startups Map — Agentic AI Vendors by CategoryPrompt Security · undated page, accessed October 27, 2026 · Tier A
  8. [8]About this Map & Methodology — AI Security Startups MapPrompt Security · undated page, accessed October 27, 2026 · Tier A
  9. [9]OneClaw DashboardPrompt Security · undated page, accessed November 10, 2026 · Tier A
  10. [10]Prompt Security Pros and Cons | User Likes & DislikesG2 · undated page, accessed November 10, 2026 · Tier C

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