Job title: Senior Developer Evangelist

Location: London; full in-office working as default

Start date: ASAP

Reports to: CRO, with dotted line to CTO and CEO

Compensation: £60k–£90k base (depending on experience) plus equity

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 (prior experience in software engineering and comfortable understanding developer workflows, reading research papers, evaluating model behaviours 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