Senior AI Engineer

Cornerstone VC; Greater London; On-site; GBP 70,000 - 100,000; Full time

Job summary

Capsa AI is looking for a Senior AI Engineer in London, UK, to design and ship core AI capabilities critical for investment decisions. The engineer will work directly with founding engineers to create impactful solutions at a rapidly growing AI firm.

Successful candidates will have strong backgrounds in Python, LLMs, and AI/ML systems, ready to deeply engage with innovative technology in a fast-paced environment.

Qualifications

• Four or more years building production software, focusing on AI/ML at a startup or tech firm.
• Experience shipping entire features or products with measurable impact.
• Strong technical toolkit including Python and experience with LLMs.

Responsibilities

• Design and ship core AI capabilities for investment expertise.
• Integrate new data sources for improved analysis.
• Uphold coding standards and avoid technical debt.

Skills

Strong Python

LLM experience (OpenAI, Anthropic)

Agent frameworks

RAG pipelines

Vector databases

Tools

FastAPI

Postgres

ElasticSearch

Job description

The AI Operating System for Private Capital.

Capsa AI

Private capital funds have to find potential investments, research and analyse them thoroughly, monitor them over time, drive improvements, and decide when to buy and sell. They’ve got to see through the marketing. They’ve got to outbid the competition. And they’ve got to learn from every deal they do. Historically, these processes have run on people, we are building the AI Operating System that will run them in the future.

We’re focused, ambitious, and obsessed with building a category-defining company. In the last 12 months we’ve grown ARR 15x, achieved product–market fit with leading multi‑billion‑dollar PE firms, and expanded across the US, UK, and Europe. Now we’re doubling down: we’ve raised a large Series A from top‑tier VC investors to scale the team. We’re hiring hyper‑talented people who want to work at the forefront of AI and revolutionise an industry.

At a glance

• Role: Senior AI Engineer
• Location: London, UK (Hybrid, in‑person 4 days per week)
• Team: Engineering
• Compensation: Top of market. Competitive base + OTE

The role

Take what you already know about AI systems, or about building at the frontier, into a category-defining company. A fast track to owning the infrastructure that powers decisions at the world's largest PE firms.

You’ll design and ship the core AI capabilities that sit at the heart of our platform, working directly alongside our founding engineers and CTO. Whether you’ve built production LLM systems, designed agentic architectures, or pushed the limits of RAG and reasoning chains, you bring depth most engineers don’t have, and the job is to point that depth at problems the industry has never had good tooling for.

This isn’t a place to maintain someone else’s codebase. We hire engineers who want to own things end-to-end from day one, and we give responsibility based on impact, not seniority. Strong execution is the fast track to shaping the technical direction of a high‑growth AI company, building alongside a founding team that will back your best ideas.

The opportunity

• Build the agent’s brain. Design and ship features that give our AI genuine investment expertise, the kind that makes analysts faster and makes partners take notice.
• Push the architecture forward. Prompts, reasoning chains, agent design. You own the quality and reliability of what the model produces, not just the code that runs it.
• Stay at the frontier. Evaluate new models, techniques, and research as they drop. When something better exists, you’re the one who brings it in.
• Expand what the agent can see. Integrate new data sources into the loop and increase the depth and breadth of analysis the platform can perform.
• Keep the codebase clean. Uphold rigorous standards across everything you ship. Tech debt is a tax on velocity, and you don’t let it accumulate.

Recent projects include

• Agentic assistant with a finance-focused toolkit and advanced document authoring features
• Scalable document ingestion and indexing pipeline
• In‑house, streaming‑first agent framework
• AI-assisted document editor

Track record

• Engineering depth, not just exposure. Four or more years building production software, with meaningful time spent on AI/ML systems at a venture‑backed startup or top tech firm -not as a side project, as the core of the work.
• You’ve shipped things that mattered. Entire features or products taken from ideation to production, with impact you can speak to. If you can’t point to what changed because of your work, that’s a flag.
• The right technical toolkit. Strong Python, hands‑on experience with LLMs (OpenAI, Anthropic, open‑source), agent frameworks, RAG pipelines, vector databases, and backend infrastructure like FastAPI, Postgres, and ElasticSearch, or close enough that the gaps close fast.
• Domain curiosity, not just technical ability. You go deep on the problem, not just the implementation. You care about what the product does for the person using it, and that shows in how you build.
• Comfortable at pace. Fast-moving environments are where you do your best work, not something you tolerate.

How you operate

• Low ego, high ownership. You want to be part of building something that matters more than you want a title that says so.
• Hungry and resilient. Start‑up pace is the appeal, not the trade‑off. Rejection doesn’t slow you down.
• Bias for action over planning theatre. You move with incomplete information and adjust as you go.
• Genuinely curious about AI. Using it, breaking it, building it into how you work.

If this opportunity excites you

We’d like to meet you. Initial conversations are direct and substantive, going deep on the work, the team, and what you’d own in the first six months.

Capsa AI provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability, genetics, sexual orientation, gender identity, or gender expression. We are committed to a diverse and inclusive workforce and welcome people from all backgrounds, experiences, perspectives, and abilities.