Security Researcher
Antigen · San Francisco, CA, US · Y Combinator Fall 2025
- Salary
- $150K - $220K
- Equity
- 0.50% - 1.00%
- Location
- San Francisco, CA, US
- Type
- Full-time
- Experience
- 1+ years
- Visa
- US citizen/visa only
- Posted
- 10 Sep 2026
- Listed until
- 23 Nov 2026, or when it closes
Information SecuritySoftware SecurityAI Agents
About the role
Antigen builds cybersecurity agents and the infrastructure to safely deploy and scale them in enterprise and government environments. Using open-source models and partnerships with frontier labs, we're pushing the frontier of what cyber agents can do.
We're looking for security researchers to join us full-time in San Francisco. You'll be an expert-in-the-loop - driving our agents into real environments, finding where they break down, and collaborating with our research team to make them more capable.
Day to day, this means deploying our agent (tCell) against complex systems, observing how it chains attacks and where it gets stuck, stepping in where it lacks understanding, and turning that into research that improves the agent. You should be a strong offensive security practitioner who's genuinely curious about how AI agents behave in adversarial settings.
We're backed by YC, Lightspeed, Susa Ventures, and DST Global.
Apply on Work at a Startup ↗ Applications go to Antigen directly. CISO AI takes no fee and has no part in hiring.
CISO AI lists open roles at Y Combinator startups and at the portfolio companies of Australian venture funds, read daily from their own boards. This role is Antigen's own listing; it leaves this page the day it leaves their board.