Founding Enterprise Account Executive (Defence)

Location: London; in-office working as default

Start date: ASAP

Reports to: Chief Commercial Officer

Cosine is a UK sovereign AI model lab that has built 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 trains LLMs 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 one of the only available managed products 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 are about to kick off our first live pilots with defence primes and are now scaling our defence go‑to‑market motion.

The role involves owning and closing complex enterprise deals across defence primes, government agencies, and national security organisations. You will navigate highly regulated procurement environments and work closely with senior technical, security, and programme stakeholders to turn pilots into long‑term production deployments. This role is ideal for someone who has successfully hunted and closed new logo enterprise deals within defence or government, particularly selling developer tooling, infrastructure, security, or platform technologies into mission‑critical engineering teams.

What you’ll do:

• Own the full sales cycle across defence and government accounts, from targeted outbound and partner‑led sourcing through to close.
• Hunt and develop new defence opportunities, including direct relationships with defence primes, government departments, and classified programme teams.
• Lead complex, multi‑stakeholder sales processes involving engineering leadership, security, procurement, and programme owners.
• Design and manage pilots and technical evaluations, defining success criteria aligned to mission outcomes, security constraints, and operational readiness.
• Build deal strategies that account for long procurement timelines, framework agreements, and partner ecosystems.
• Work closely with product, engineering, and leadership to shape Cosine’s defence positioning, deployment models, and roadmap priorities.
• Help formalise Cosine’s defence go‑to‑market playbook, including qualification, pilot structures, accreditation pathways, and scale‑out strategies.
• Maintain rigorous pipeline management, forecasting, and CRM hygiene across long‑cycle opportunities.

What we’re looking for:

• A demonstrated track record of closing complex enterprise deals within defence, government, or national security environments.
• Experience selling developer tooling, infrastructure, security, or data platforms into large, technically sophisticated organisations.
• Background at, or selling products comparable to, companies such as AWS, Kubernetes, Terraform, GitHub, Datadog, Grafana, Cloudflare, GCP, or similar developer‑first or infrastructure platforms.
• Strong understanding of defence and government procurement processes, including frameworks, primes, and compliance requirements.
• Credibility engaging with senior technical, security, and programme stakeholders in high‑assurance environments.
• Comfort operating in environments with long sales cycles, multiple decision‑makers, and strict security constraints.
• Strong written and verbal communication skills, with the ability to communicate complex technical concepts clearly to both technical and non‑technical audiences.

Nice to have:

• Experience selling on‑premise, air‑gapped, or classified systems.
• Familiarity with defence primes, systems integrators, or government procurement frameworks.
• Exposure to AI, ML platforms, or developer productivity tooling.
• Existing network within defence, government, or national security technology organisations.

Why join Cosine:

• Opportunity to sell a genuinely differentiated product into mission‑critical defence and national security environments.
• Meaningful early equity with real upside.
• Direct impact on product direction and go‑to‑market strategy.
• Small, elite team with high standards and strong technical depth.

How we work:

We are an in‑office, high‑ownership team. You will work closely with leadership, product, and engineering and play a key role in shaping Cosine’s defence and government GTM strategy. Our current tooling includes Attio, Lemlist, PostHog, Notion, Slack, and Google Workspace, with flexibility to evolve as we scale.

Equal Opportunity:

We’re an equal opportunity employer. We value diverse backgrounds and encourage applications from everyone who meets the role requirements, even if you don’t tick every box.