RunSybil delivers AI-driven offensive security and automated penetration testing that continuously probes applications, APIs, cloud, and infrastructure for exploitable vulnerabilities. Rather than relying on signature scanning, it reasons adversarially about a system the way an elite human researcher would, validating exploitability in real time and surfacing real attack chains, with security feedback on every pull request and deployment. RunSybil was co-founded in 2023 by Ari Herbert-Voss, who in 2019 became OpenAI's first security research hire, and Vlad Ionescu, who previously led offensive security red teams at Meta. In March 2026 the company raised a $40M round led by Khosla Ventures. Customers include Notion, Cursor, Turbopuffer, and Baseten.
RunSybil
ActiveAI offensive security that pentests like an elite researcher
Total raised
$40M
1 round
Stage
Series A
Mar 2026
Team
11-50
since 2023
Pricing
Enterprise
Founded
2023
San Francisco, United States
Agent-ready
API
Score 40/100
Continuous AI-driven penetration testing
Adversarial reasoning over the full stack
Real-time exploitability validation
Attack chain discovery
Security feedback on every pull request
Coverage across code, APIs, cloud, and infrastructure
Per-deployment testing
Prioritized, exploitable findings
40/100
Developing
MCP server
Public API
Webhooks
OAuth 2.0
SDKs
Mar 2026 Series A $40M ● Khosla Ventures
Capital network
$40M raised ·1 backer·10 network links
- Backers1
- Shared portfoliocompanies these backers also fund
- Extended networkfunds that co-invest alongside them
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- What does RunSybil do?
- RunSybil is an AI offensive security platform that continuously pentests applications and infrastructure, reasoning about exploitable attack chains like a human researcher.
- Who founded RunSybil?
- RunSybil was co-founded in 2023 by Ari Herbert-Voss (OpenAI's first security research hire) and Vlad Ionescu (former Meta red team lead).
- How much has RunSybil raised?
- RunSybil raised $40M led by Khosla Ventures in March 2026.
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