Software Engineer, Cloud Infrastructure at Cosine

Location: London; full in-office working as default

Start date: ASAP

Reports to: CTO

Compensation: £60 - 90k + Equity

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.

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.

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.

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.
• Experience running large-scale orchestration systems such as Kubernetes.
• 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.

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 is an equal opportunity employer. We value diverse backgrounds, perspectives, and ways of thinking, and we’re committed to creating an inclusive and respectful workplace. We encourage applications from anyone who meets the role requirements, even if you don’t meet every single qualification. If you need reasonable adjustments at any stage of the hiring process, we’re happy to discuss them.