Senior Platform Engineer

About Cosine

Fully Agentic SWE

The role

### **About the Role**We’re looking for a Senior Platform / Infra Engineer to own the core infrastructure that powers Cosine’s products — from Kubernetes and deployment pipelines to networking and platform services.You’ll design and run the “paved road” that our engineers, researchers, and customers build on: reliable Kubernetes clusters, fast and safe CI/CD, solid observability, and hardened environments for demanding enterprise and on-prem deployments. You’ll also wear a classic “DevOps/SRE” hat: thinking in SLOs, running incident response, and keeping us up even as we move quickly.This is a high-ownership role at a fast-paced, venture-backed Silicon Valley startup. You’ll work directly with founding engineers and leadership, and your decisions will materially shape how we build and ship products.---### **What You’ll Do*** **Own core infrastructure** * Design, operate, and evolve our Kubernetes-based platform (EKS or similar), including cluster topology, node groups, autoscaling, and multi-environment isolation. * Manage supporting cloud resources: container registries, load balancers, queues, caches, and data infra needed to run our APIs and agents.* **Build the deployment & tooling layer** * Design and maintain CI/CD pipelines for image builds and infra rollouts (e.g. Pulumi/Terraform + Helm/Docker). * Implement safe rollout strategies (blue/green, canary, staged rollouts) and fast rollback paths. * Build internal tools and abstractions that make it easy for product teams to self-serve infra safely.* **Own reliability & operations (SRE-ish)** * Define and track SLOs/SLIs for key services (latency, error rates, availability). * Improve our observability stack (metrics, logs, traces, alerts) so issues are obvious, actionable, and debuggable. * Participate in the on-call rotation, lead incident response when needed, and drive blameless post-mortems and fixes.* **Shape networking & security** * Design and maintain networking: VPCs, subnets, ingress/egress, service meshes / L7 routing, DNS, and TLS. * Implement least-privilege access via IAM, secure secret management, and hardened configurations for multi-tenant and isolated customer environments. * Help design patterns for secure enterprise and on-prem / regulated deployments.* **Partner with product & research** * Work closely with application, ML, and research teams to understand their needs and translate them into reusable infra building blocks. * Provide guidance on “how to run this in production” — capacity planning, failure modes, and operational readiness reviews.---### **You Might Be a Great Fit If You*** **Have strong experience** * 5+ years building and operating production infrastructure on a major cloud (AWS, GCP, or Azure). * Significant hands-on experience running **Kubernetes** in production (EKS/GKE/AKS or self-managed): * Cluster upgrades, autoscaling, node group design, and multi-env setups. * Helm or similar for packaging services.* **Think in infrastructure-as-code** * Deep experience with IaC tools (Pulumi, Terraform, CDK, or similar). * Comfortable managing infra changes via code review, CI, and automated rollouts.* **Care deeply about reliability** * Have owned the uptime and performance of user-facing systems. * Comfortable participating in (and improving) on-call rotations and incident management. * Experience setting up / tuning observability (Prometheus, Grafana, CloudWatch, OpenTelemetry, etc.).* **Build great tooling & abstractions** * You’ve built internal tools, libraries, or platforms on top of cloud providers so product teams can move faster with fewer foot-guns. * You think about developer experience and “golden paths,” not just raw infra.* **Are comfortable in code** * Strong scripting and programming skills in at least one modern language (e.g. TypeScript, Go, Python). * Happy to dive into app code when needed to debug a production issue or improve an integration.* **Have the startup mindset** * Enjoy working in a fast-moving environment with evolving priorities and incomplete specs. * Bias toward pragmatic solutions: ship something small, measure, iterate. * Communicate clearly, give/receive direct feedback, and collaborate across functions.---### **Nice to Have (Not Required)*** Experience with: * AWS primitives like EKS, ECS/Fargate, ECR, SQS, ElastiCache/Redis. * Argo CD or other GitOps tools for Kubernetes. * On-prem, air-gapped, or regulated industry deployments (e.g. finance, healthcare). * AI/ML infrastructure (GPU workloads, model hosting, feature stores).* Prior experience as an early infra / platform hire at a startup.

Skills

• Amazon Web Services (AWS)
• Kubernetes