Founding Software Engineer

Calyptus; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Calyptus is recruiting an experienced software engineer for an AI/ML focused role. You will own the models behind our AI agents, manage data pipelines, and oversee production deployments to ensure fast, reliable decisions.

You will work closely with the CTO, shaping the AI/ML roadmap and evaluating model performance with rigorous measurement. The team operates with a flat structure and rapid experimentation.

Qualifications

• 5+ years shipping production software including ML models.
• Experience with agent-based ML workflows and evaluation.
• Commercially minded, focused on revenue impact.

Responsibilities

• Own the AI & ML roadmap and model production lifecycle.
• Develop data pipelines and train/infer models in production.
• Collaborate with CTO and cross-functional teams to deliver results.

Skills

Python

TypeScript

ML models

Production software

Data pipelines

Ad-tech

Job description

This role is being recruited by Calyptus on behalf of one of our clients.

Calyptus is a specialist recruitment partner helping startups and high-growth technology companies hire across engineering, product and design.

What to expect

• We’ll review your application and, if your experience is a strong match, one of our team will be in touch
• We’ll support you throughout the interview process and keep you updated at each stage
• If this particular role isn’t the right fit, we may consider you for other relevant opportunities with our clients

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We are looking for an experienced software engineer who understands AI & ML pipelines and has shipped models into production.

Everything we build depends on understanding how AI agents read, cite and recommend: which brands get cited, how well an ad fits a page and the question an agent is answering, and what an impression to an agent is actually worth. You'll own the models behind all of it, from our citation engine and brand extraction today to the models that will match and price ads in our auction tomorrow.

You’ll work closely with our CTO, and own our AI & ML roadmap, the data pipelines your models learn from, and the infrastructure they run on. Knowing what good looks like, and proving it with measurement, is what we’re hiring for.

Our structure is intentionally flat, with influence earned through skill & context. Our codebase is shared rather than siloed, and we move fluidly across priorities as a team. We have dozens of agents working alongside us every day, so we go from an idea to a measured experiment in hours, and from a proven result to production just as quickly. It's how a small team builds at the pace of one ten times our size.

WHO YOU ARE

• You've shipped models into live systems where speed and reliability matter, and you know the difference between a good demo and a good product.
• You measure before you believe. You build the evaluation first and trust numbers over impressions.
• You're commercially minded, prioritising what moves revenue rather than what's interesting to build. You'll hear directly from brands and publishers on what your models are worth to them.
• You're comfortable in a small, high-trust team, happy to pick up whatever's needed.
• Python & TypeScript fluency preferred.
• Experience in ad-tech, search ranking or recommendations is a strong plus.

MUST HAVES

• 5+ years of shipping production software, including ML models and the pipelines behind them.
• You work agentic-first. Agents speed up your loop from idea to experiment to production; your judgement decides what's worth testing and what goes live.

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Genuine opportunities

Every role advertised by Calyptus is a live position we’re actively recruiting for. Some clients prefer to remain confidential during the early stages of the hiring process. When that’s the case, certain company details may be shared later in the process.

Why work with Calyptus?

• Access opportunities with ambitious startups and high-growth technology companies
• Direct support from experienced specialist recruiters
• Honest feedback and clear communication throughout the hiring process
• Long-term career support, not just a single job application