Founding Security Infrastructure Engineer (US)

We are looking for a Founding Security Infrastructure Engineer with 5+ years of experience to own and build Sela's entire security and privacy program from the ground up. This is a true 0-to-1 role, you'll be the first dedicated security hire, responsible for everything from cloud infrastructure security and access controls to compliance and data protection across a complex AI voice platform. The ideal candidate has built or matured a security function at a fast-growing startup (Seed through Series C) and is comfortable being deeply hands-on, not just defining policies, but implementing the systems and controls. You'll need strong judgment to prioritize high-impact security work without slowing down a team that's scaling rapidly.

What you will be doing

• Building and owning the security program end-to-end, cloud infrastructure security, identity and access management, secrets management, encryption, and data isolation across AWS

• Owning compliance efforts including SOC 2 Type II, managing the observation period, coordinating with external vendors, and ensuring the team follows internal security policies

• Designing and implementing controls for how internal AI agents access systems, auditing, guarding against unauthorized access, and establishing AI use policies

• Managing permission controls and data protection for sensitive customer data, determining what's tokenized, anonymized, and who has access to what, without slowing down development

• Leading customer-facing security reviews, managing third-party penetration testing, and evaluating which external tools are approved for use based on their security posture