YC Security startups
124 Y Combinator companies in Security, 19 of them from the last four batches. Its share of recent batches is 2.4%, down from 2.6% in the four batches before. About 48% are AI companies by YC’s tags.
- Signal
- Crowded
- Since 2025
- 35 vs 24 in 2023–24
- Acquired or public
- 30%
- Listed as inactive
- 17%
Share of each batch
Security companies as a share of each YC batch since 2015.
Newest entrants
Of 53 Security companies from batches up to 2021, YC lists 16 as acquired, 0 as public, 28 as active and 9 as inactive.
- Armorer Labs F26 · Continuous security verification for AI agents in regulated industries
- DeepMark F26 · A live watermark inside AI voice that survives phone calls
- Latent F26 · Catch wrong LLM answers before your customers do
Building in Security?
Open problems and funding on Questd for ai & infrastructure.
- Y Combinator · Requests for Startups
- Andreessen Horowitz · Big Ideas 2026
- Index Ventures · Investment Focus 2026
- IVP · Investment Focus 2026
Security companies, newest first
124 companies
- Armorer LabsAI
Continuous security verification for AI agents in regulated industries
Fall 2026Security2San Francisco, CA, USA - DeepMark
A live watermark inside AI voice that survives phone calls
Fall 2026Security5San Francisco, CA, USA - LatentAI
Catch wrong LLM answers before your customers do
Fall 2026Security1San Francisco, CA, USA - OpenHackAI
Always-on AI security engineer
Fall 2026Security1San Francisco, CA, USA - VerdunAI
The world's most advanced security monitoring service
Fall 2026Security6Los Angeles, CA, USA - FabraixAI
The world's frontier hacker of AI agents.
Summer 2026Security2San Francisco, CA, USA - NebuSecAI
Autonomous AI defense system for cyber attack
Summer 2026Security4San Francisco, CA, USA - PalisadeAI
AI that finds and fixes OS-level vulnerabilities across device fleets
Summer 2026Security1San Francisco, CA, USA - TraceforceAI
CrowdStrike for AI Agents
Summer 2026Security2San Francisco, CA, USA - TridentAI
Autonomous offensive security agents. The best defense is offense
Summer 2026Security4San Francisco, CA, USA - Verdict MachineAI
AI cybersecurity for financial institutions' digital assets
Summer 2026Security4Tel Aviv-Yafo, Tel Aviv District, Israel - Clawvisor
The Authorization Layer for AI Agents
Spring 2026Security1San Francisco, CA, USA - RASPIRE
Autonomous Runtime Security
Spring 2026Security5Cairo, Cairo Governorate, Egypt - TolmoAI
Tolmo is the AI security platform that secures every layer of cloud…
Spring 2026Security12San Francisco, CA, USA - Agentic FabriqAI
The control plane for AI agents.
Winter 2026Security2San Francisco, CA, USA - BeeSafe AI
Frontier AI Defenses for Social Engineering Attacks
Winter 2026Security3San Francisco, CA, USA - Crosslayer Labs
Protect, monitor and defend your Internet presence
Winter 2026Security3New York City, NY, USA - Lexius
AI for Corporate Security Cameras
Winter 2026Security3San Francisco, CA, USA - Parameter
AI pentesting, that works!
Winter 2026Security14San Francisco, CA, USA - Kestrel AIAI
AI Agents for Platform Engineering
Fall 2025Security2San Francisco, CA, USA - Multifactor
Zero-trust authentication, authorization, and auditing for AI agents
Fall 2025Security6San Francisco, CA, USA - Veria LabsAI
Continuous AI pentesting that finds and fixes vulnerabilities
Fall 2025Security3San Francisco, CA, USA - AlterAI
Privileged Access Management for AI Agents
Summer 2025Security2New York City, NY, USA - ContextFortAI
Visibility and Controls for Browser Agents
Summer 2025Security2San Francisco, CA, USA
Sector is YC’s own label in its public company directory. See the methodology, every sector side by side, or browse open problems worth solving.