Founding Engineer at Cardinal

As a Founding Engineer, you'll architect and build the core AI agents and infrastructure that power precision outbound at scale — then make them accessible through beautiful, intuitive interfaces. You'll work directly with customers, shape product direction, and own critical systems that drive revenue for 40+ YC companies and growing. AI agents that discover hyper-targeted leads by understanding ideal customer profiles, conference attendees, hiring signals, and more. Real-time content monitoring systems that track what prospects are posting, sharing, and engaging with across social platforms. Multi-channel sequence orchestration across email and LinkedIn, managing dozens of email domains and sender accounts. Enterprise-grade infrastructure that scales to hundreds of concurrent users — multi-tenant architecture with role-based access control, end-to-end encryption, SOC 2-ready audit logging, and rate limiting built in from day one. Polished user interfaces that turn complex outbound workflows into experiences sales teams can set up in minutes. 1–6 years of experience building production systems and user-facing features. Full-stack expertise — strong with TypeScript, React, Next.js,