Antigen is an AI adversary for the enterprise. Its platform continuously maps, exploits and secures a company's attack surface through nightly automated offensive testing and monthly human red-team assessments, then ships fixes for review and re-runs the original exploit to verify each remediation. Findings arrive with traces, reproduction steps and remediation in GitHub, Linear or the Antigen Platform. Antigen was founded by Abdullah Nauman and Saad Jamal, is part of Y Combinator's Fall 2025 batch, and is backed by Lightspeed, DST Global and Susa Ventures.