Infrastructure Security Engineer

Modal•New York, NY

About The Position

Modal provides the infrastructure foundation for AI teams, offering instant GPU access, sub-second container startups, and native storage to simplify model training, batch jobs, and low-latency inference. They serve thousands of customers, including Lovable, Scale AI, Substack, and Suno. Modal is a rapidly growing company with offices in NYC, SF, and Stockholm, having achieved 9-figure ARR and recently secured a Series B funding at a $1.1B valuation. Their investors include Lux Capital, Redpoint Ventures, Amplify Partners, and Elad Gil. Joining Modal offers significant growth opportunities within one of the fastest-growing AI infrastructure organizations. The team comprises creators of popular open-source projects, academic researchers, international olympiad medalists, and experienced engineering and product leaders. The Infrastructure Security Engineer role is focused on designing and securing the core systems that power Modal's platform. This involves embedding security directly into the infrastructure, covering aspects from container isolation and orchestration to identity and secrets management within a multi-tenant, cloud-native environment. It is a hands-on, deeply technical position that requires close collaboration with engineering teams to establish secure primitives and ensure the platform's resilience, scalability, and trustworthiness by design, with an emphasis on practical system implementation over compliance or policy.

Requirements

Experience securing cloud-native infrastructure and distributed systems in production
Background in infrastructure, backend, or security engineering
Experience working in multi-tenant or high-scale environments
Strong understanding of containerization and orchestration systems (e.g., Kubernetes or similar)
Experience designing or securing isolation mechanisms in multi-tenant systems
Solid understanding of authentication, authorization, and service identity models
Experience with secrets management and secure handling of credentials
Strong foundation in networking concepts (segmentation, service communication, access boundaries)
Builder mentality, you design and implement, not just review
Pragmatic approach to security in fast-moving environments
Comfortable working deeply with engineers and influencing system design

Nice To Haves

Experience with sandboxing or runtime isolation technologies (e.g., gVisor, Firecracker, seccomp, or similar)
Familiarity with kernel-level or low-level isolation primitives
Experience securing Kubernetes or similar orchestration systems in production
Background in developer infrastructure, compute platforms, or multi-tenant systems

Responsibilities

Design and improve isolation mechanisms for multi-tenant workloads (containers, sandboxing, execution environments)
Strengthen boundaries between customers, workloads, and internal systems
Identify and mitigate risks in distributed, dynamic compute environments
Secure and harden containerized workloads and orchestration systems (e.g., Kubernetes or similar)
Improve workload isolation, scheduling boundaries, and runtime protections
Evaluate tradeoffs in multi-tenant execution models
Design and improve authentication and authorization systems across services
Implement strong service-to-service identity and least-privilege access patterns
Improve access controls across infrastructure and internal systems
Build and maintain systems for securely managing secrets, tokens, and credentials
Improve rotation, auditing, and access controls
Reduce secret sprawl and integrate secure patterns into developer workflows
Secure cloud environments across providers (AWS, GCP, etc.) with a focus on consistency and portability
Improve network boundaries, service segmentation, and access controls
Embed security into infrastructure-as-code and deployment systems
Work closely with product and infrastructure teams to design secure systems from the ground up
Review architecture and code for security risks and provide actionable guidance
Identify patterns in risks and drive cross-cutting improvements