Security Engineer

ABOUT ASSEMBLED Assembled helps companies scale great customer support. As consumers, we’ve all been there. You need help, you’re stuck on hold or going in circles with an AI, and your problem still isn’t solved. Behind great support is a complex operational problem: thousands of people and AI agents working across teams, time zones, and products as new problems emerge. Assembled gives support leaders the tools to manage that complexity, from AI agents that resolve customer issues to software that forecasts demand, builds schedules, and makes intraday adjustments. More than 400 companies, including DoorDash, Salesforce, Stripe, and Sephora, trust Assembled https://www.assembled.com/customers. We've raised $71M from NEA, Emergence Capital, Stripe, and Basis Set Ventures and have offices in San Francisco, New York, and London. ABOUT THE ROLE Assembled operates at the intersection of tens of millions of untrusted customer conversations annually, hundreds of thousands of support professionals, and the sensitive data and privileged access they need to get issues fixed. You'll lead application security across our SaaS and AI products as part of our infrastructure team within Engineering. Working directly with product managers and other engineers, you'll establish our product security practices, influence architecture, and build tooling to manage vulnerabilities from discovery and prioritization through remediation and verification. This is a high-ownership role with broad scope to reshape security at Assembled. WHAT YOU'LL BE RESPONSIBLE FOR - Product and application security. Lead threat modeling, secure design reviews, and vulnerability management across our SaaS and AI products and the underlying infrastructure. - Tooling and automation. Integrate and automate controls for secrets, access, and dependency security within our engineering workflows and CI/CD pipelines. - Application security testing. Establish and maintain code, dependency, and secrets scanning, alongside dynamic application security testing. Partner with third-party penetration testers and manage external vulnerability reporting and triage. - Secure practices. Develop secure design and coding training for engineers. Establish clear processes for routing security issues to engineering owners and following through on fixes. - Incident response. Respond to security incidents involving application vulnerabilities, coordinating remediation efforts and post-incident improvements. - Partner on security assurance. Bring technical depth to customer security conversations and partner with Finance/Ops on the technical side of SOC 2 and assurance work. Turn recurring customer needs into better product and engineering decisions. - Shape the team and roadmap. You’ll start as our sole dedicated security hire. You’ll set a foundation for how the security function should involve, including where we hire or bring in outside expertise.Turn recurring customer needs into better product and engineering decisions. Examples of projects you could lead: - Ship adversarial detection for our customer-facing voice agents. - Build an automated dependency-patching pipeline connected to our AI code generation tools (Devin, Codex, Claude Code, Cursor). - Secure workforce actions like time off and shift swap requests initiated through Slack, calendar, and HRIS integrations. Our tech stack: - Frontend: TypeScript, React - Backend: Go, Python - Data: PostgreSQL, Redis, Snowflake - Cloud and infrastructure: AWS, Kubernetes, Karpenter - LLMs: Claude, GPT, Gemini Flash, and open-source models ABOUT YOU - Security engineering expertise. You have 3+ years of hands-on application security experience, including threat modeling, security code reviews, and vulnerability remediation. - Strong software engineering fundamentals. You have experience writing and reviewing production code, and knowing when to work alongside the engineer closest to the system. - See the whole picture. You understand that helping us succeed responsibly means finding ways to build and ship while taking real risks seriously. Engineers trust you to find a path forward and help turn ambitious ideas into products customers can trust. - AI-pilled. You actively use AI tools for security investigation, testing, or remediation and can evaluate their limitations. You have a point of view on how this changes the product threat model and how the security role evolves. People get to this kind of role through many paths. Your background might be in product security, application security, security engineering, DevSecOps, infrastructure, technical consulting, or something less conventional. We care most about how you think and what you have owned. NICE TO HAVE - Background with large-scale, multi-tenant SaaS applications handling sensitive customer data - Experience securing AI/ML applications, including prompt injection, unauthorized tool use, and