Devops Engineer

Job Overview

Devops Engineer Location London Office Employment Type Full time Location Type On-site Department Product & Engineering Compensation £60K – £90K • Offers Equity

About Cosine

At Cosine, we’re building autonomous AI engineers that plan, write, and ship code inside real development workflows. Cosine is designed for on-premise and virtual private cloud (VPC) deployments, including fully air-gapped environments. We build our agent tooling entirely in-house and post-train open-source models to deliver reliable, enterprise-grade coding performance in security-critical settings. In 2024, Cosine achieved a 72% score on OpenAI’s SWE-Lancer benchmark, placing us among the strongest real-world software-engineering AI systems evaluated. YC-backed and well-funded, Cosine was founded by experienced operators focused on building dependable, production-grade AI. This role is based in our Hoxton office, five days a week, because close collaboration, fast feedback, and shared context matter for the problems we’re solving.

The Role

We’re looking for a Devops / 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.

Key Responsibilities

• 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.

Required Qualifications

• 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.