About Us:Modal provides the infrastructure foundation for AI teams. With instant GPU access, sub-second container startups, and native storage, Modal makes it simple to train models, run batch jobs, and serve low-latency inference. We have thousands of customers who rely on us for production AI workloads, including Lovable, Scale AI, Substack, and Suno.We're a fast-growing team based out of NYC, SF, and Stockholm. We've hit 9-figure ARR and recently raised a Series B at a $1.1B valuation. Our investors include Lux Capital, Redpoint Ventures, Amplify Partners, and Elad Gil.Working at Modal means joining one of the fastest-growing AI infrastructure organizations at an early stage, with many opportunities to grow within the company. Our team includes creators of popular open-source projects (e.g. Seaborn, Luigi), academic researchers, international olympiad medalists, and experienced engineering and product leaders with decades of experience.The Role:We’re looking for an Infrastructure Security Engineer to design and secure the core systems that power our platform. This role focuses on building security directly into our infrastructure—from container isolation and orchestration to identity and secrets management in a multi-tenant, cloud-native environment.You’ll work closely with engineering teams to define secure primitives and ensure our platform is resilient, scalable, and trustworthy by design.This is a hands-on, deeply technical role focused on real systems, not compliance or policy.What You'll Do:Platform & Runtime SecurityDesign and improve isolation mechanisms for multi-tenant workloads (containers, sandboxing, execution environments)Strengthen boundaries between customers, workloads, and internal systemsIdentify and mitigate risks in distributed, dynamic compute environmentsContainer & Orchestration SecuritySecure and harden containerized workloads and orchestration systems (e.g., Kubernetes or similar)Improve workload isolation, scheduling boundaries, and runtime protectionsEvaluate tradeoffs in multi-tenant execution modelsIdentity & Access ManagementDesign and improve authentication and authorization systems across servicesImplement strong service-to-service identity and least-privilege access patternsImprove access controls across infrastructure and internal systemsSecrets & Key ManagementBuild and maintain systems for securely managing secrets, tokens, and credentialsImprove rotation, auditing, and access controlsReduce secret sprawl and integrate secure patterns into developer workflowsCloud & Infrastructure SecuritySecure cloud environments across providers (AWS, GCP, etc.) with a focus on consistency and portabilityImprove network boundaries, service segmentation, and access controlsEmbed security into infrastructure-as-code and deployment systemsEngineering PartnershipWork closely with product and infrastructure teams to design secure systems from the ground upReview architecture and code for security risks and provide actionable guidanceIdentify patterns in risks and drive cross-cutting improvements