Cosine

Join Our Team At Cosine, we're pioneering the integration of human reasoning into artificial intelligence. As a member of our team, you'll be at the forefront of cutting-edge technology, working to shape the future of AI with our groundbreaking synthetic data generation and RFT techniques. Why Work With Us? • Be part of a trailblazing company leading innovation in AI. • Work alongside a dedicated team of experts passionate about AI and technology. • Engage in challenging and rewarding work that makes a real impact on the advancement of AI. Responsibilities On this team you will build end-user products (developer workflow tools) that use Cosine's LLM and AI tech in order to augment developers’ capabilities for our users. We're building tools for ourselves. We are our own customer as engineers so you should be obsessed about the developer experience. Skills & Experience Experience building reactive applications (React, Vue, Rails, etc) that work across multiple platforms and that are highly interactive Experience with NextJS and typescript Comfortable with back-end development Design back-end APIs Expose and use rest endpoints Experience with developer experience tools Worked on CI/CD pipelines Worked with containerization Experience with testing code Unit testing Integration testing Test performance optimization Programming languages Experience in either React, Vue, Typescript (we're open to people from other languages) Knowledge of Node.js, Python or Go is a plus Other relevant tools/experience DevOps: Git, AWS, Docker, PNPM, GitHub Actions Monitoring and alerting (Grafana, Axiom) Experience with feature flagging mechanisms (Posthog) Requirements • Minimum of 4 years of professional experience in software engineering. (Looking for mid to senior level candidates) • Proven expertise and expertise in the programming language of your choice. • Familiarity with AI technologies such as OpenAI, ChatGPT, Anthropic, ASTs, Github, Knowledge Graphs, Retrieval Augmented Generation, and Fine Tuning. • Strong problem-solving skills and the ability to work e]ectively in a collaborative team environment. • Excellent communication and interpersonal skills.

Cosine at a glance Cosine is an autonomous, on-premise coding agent post-trained on human reasoning data to deliver unmatched software-engineering accuracy, security, and speed for regulated enterprises What makes us unique is our in-house ML research lab that post-trains LLMs (e.g. Nova, gpt-oss, Kimi) on proprietary software-engineering reasoning data to dramatically increase their coding accuracy. In 2024 this gave us a world-leading score of 72% on OpenAI’s SWE-Lancer benchmark Cosine is now the only available managed product that can be fully air-gapped and deployed on premises, exciting many bulge bracket but extremely risk sensitive and strict enterprises that have rejected all other solutions on the market. We've got our first pilots up and running with global investment banks and defence primes The role At Cosine we work with some of the world’s most sophisticated engineering teams and forward-thinking enterprises. Now we’re looking for someone who can help us tell that story with clarity, technical depth, and creative polish. We are therefore hiring a Senior Developer Evangelist to own and scale Cosine’s technical storytelling across written, visual, and video formats. This is a rare hybrid role for someone who is: Deeply technical (comfortable reading research papers, evaluating model behaviours, understanding developer workflows, inspecting architecture diagrams, and explaining nuanced ML concepts) Also a world-class communicator who can make complex systems feel simple, exciting, and credible through writing, visualisation, and polished video content Your work will shape how enterprises, developers, policymakers, and the broader market understand Cosine’s technology and why our approach is fundamentally different. What You’ll Do Create best-in-class technical content Produce long-form written explainers on Cosine’s latest ML training techniques, agents, architecture choices, evaluation methods, and product breakthroughs. Translate research-level concepts into content that is intelligible to CTOs, engineering leaders, and technical evaluators. Produce high-quality videos that showcase the Cosine platform and explain our business. Own Cosine’s technical narrative Work with engineering, research, and product to deeply understand how Cosine works. Build a cohesive voice and style for Cosine’s technical content that reflects sophistication, clarity, and authority - particularly for an enterprise audience. Develop visual diagrams, illustrations, and product walk-throughs. Produce customer-facing case studies Create technically rigorous case studies highlighting real customer projects, training approaches, evaluation results, and post-deployment insights. Frame Cosine’s value in a way that resonates with enterprise buyers and engineering decision-makers. Elevate Cosine’s brand Explain Cosine’s value both as a ML research lab and a coding agent software provider Help the world understand the difference between “AI wrappers” and a true agentic, full-stack AI engineering platform. Ensure all content (whether written or video) communicates credibility, depth, and market-leading expertise. You’ll thrive here if you Are fluent in modern ML concepts (fine-tuning strategies, eval pipelines, agentic architectures, model training, multi-modal tool use, etc.) Can independently research a technical subject and produce high-quality content without hand-holding Have experience producing YouTube-quality video content (storyboarding, editing, motion graphics, or directing) Are obsessed with clarity and narrative structure Are energised by the idea of working closely with a research-driven engineering team Want autonomy and ownership, and enjoy operating in a fast-growing startup where you can shape the function from scratch

About the Role An Applications Engineer at Cosine works across research, engineering, product, and design to deliver advanced AI capabilities to consumers and enterprises. You will be responsible for the core infrastructure powering Cosine’s products, including our Kubernetes environments, deployment pipelines, networking stack, cloud abstractions, and foundational platform services. We build systems that enable rapid product iteration while maintaining operational excellence, with a strong emphasis on enterprise-grade reliability. Our work includes supporting large‑scale deployments for regulated industries, delivering hardened on‑premises installations, and ensuring secure, isolated environments for customers with stringent operational or compliance requirements The Cloud Infrastructure engineer develops and maintains the infrastructure abstractions that allow Cosine to ship products reliably, securely, and at scale. In this role, you will: Design and build development and production platforms that power Cosine products, enabling reliability and security at scale. Ensure our infrastructure can scale to the next order of magnitude. Contribute to a culture that values diversity, rigorous thinking, and open, direct communication. Participate in the on-call rotation to ensure reliability of the systems you build, responding to critical incidents when necessary. You Might Thrive in This Role If You: Have 5+ years of experience developing or operating core infrastructure. Have experience running large-scale orchestration systems such as Kubernetes. Have built abstractions and tooling on top of major cloud platforms. Take pride in building scalable, reliable, and secure systems. Are comfortable working in a fast-moving environment with evolving priorities. About Cosine Cosine builds infrastructure, tooling, and products that make advanced AI systems practical, powerful, and widely accessible. This includes enterprise‑grade and fully on‑premises deployments designed for customers requiring strict isolation, compliance, or custom security postures. We support bespoke model hosting, fine‑tuned and custom models tailored to domain‑specific workflows, and deep integration with customer infrastructure. Cosine also offers a collaborative coding agent platform built for teams and enterprises, enabling secure, auditable AI‑assisted software development across complex codebases. We create and deploy AI with a focus on performance, robustness, and real‑world impact. Achieving this requires a team that reflects a wide range of perspectives, backgrounds, and experiences.

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,

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,