Senior Platform Engineer, Security

About Decagon Decagon is the leading conversational AI platform empowering every brand to deliver concierge customer experiences. Our technology enables industry-defining enterprises like Avis Budget Group, Block’s Cash App and Square, Chime, Oura Health, and Hunter Douglas to deploy AI agents that power personalized, deeply satisfying interactions across voice, chat, email, SMS, and every other channel. We’re building a future where customer experiences are being redefined from support tickets and hold music to faster resolutions, richer conversations, and deeper relationships. We’re proud to be backed by world-class investors who share that vision, including a16z, Accel, Bain Capital Ventures, Coatue, and Index Ventures, along with many others. We’re an in-office company, driven by a shared commitment to excellence and velocity. Our values — Just Get It Done, Invent What Customers Want, Winner’s Mindset, and The Polymath Principle — shape how we work and grow as a team. ABOUT THE TEAM The Security Engineering team at Decagon protects the platform that powers the most advanced conversational AI agents for enterprise customers across voice, chat, email, and SMS. We build the security foundations that enable Decagon's AI agents to handle sensitive customer data with complete trust while defending against sophisticated, AI-enabled threats at massive scale. This role sits at the intersection of Security and Infrastructure. Like the rest of our Infrastructure org, we believe the best security comes from paved paths, strong SLAs, and high-quality systems that other engineers can rely on by default. Our mission is to secure magical support experiences, ensuring that AI agents and human agents can collaborate safely to help users resolve their issues while maintaining the highest standards of security and privacy. ABOUT THE ROLE We're hiring our founding Platform Engineer, Security to design, build, and operate the security infrastructure that powers Decagon's AI platform. This is a builder's role: you'll spend your time creating durable, well-engineered systems including paved paths for secure service creation, security tooling that automatically applies secure configurations, and infrastructure-as-code that makes it easy for every engineer at Decagon to do the right thing. As the first dedicated engineer at this intersection, you'll have outsized impact on how security infrastructure is built here, and you'll shape the technical direction of the infrastructure security program. You'll also help us invest in automation, observability, and self-service so the team operates with confidence. The work is close to the business. Decagon serves some of the world's most security-conscious enterprises, including major financial-services institutions, and the security platform you build directly unlocks these high-value deals. This role offers a clear runway to grow your impact across security, infrastructure, and platform engineering. IN THIS ROLE, YOU WILL - Design and implement secure, multi-tenant infrastructure that isolates customer data while enabling efficient AI model serving across our platform - Build "golden paths" for security including service templates, libraries, terraform policies, and automation, so new services are secure and production-ready by default - Own infrastructure-as-code (Terraform) and GitOps best practices, including reusable modules and policy-as-code - Expand and help operate the platforms behind alerting detection, secrets management, IAM, and automated remediation, integrating them cleanly into CI/CD and developer workflows - Partner with Security, Infrastructure, and product engineering teams to translate enterprise and compliance requirements (SOC 2, ISO 27001, GDPR) into reliable, automated technical controls - Participate in security on-call and continuously raise the bar on operability, runbooks, and incident learnings YOUR BACKGROUND LOOKS SOMETHING LIKE THIS - 5+ years building and operating producti