Senior / Staff AI Engineer

Antler Co; Greater London; Hybrid; GBP 110,000 - 190,000; Full time

Benefits offered by this job

Private healthcare insurance.

One month per year remote working.

Home-Office setup budget.

Job summary

Capsa AI in London is hiring a Staff / Senior AI Engineer to own core AI capabilities and agent infrastructure. You will design prompts, architectures, and reasonings to deliver high-quality outputs and integrate new models and data sources.

Ideal candidates have 4+ years in software engineering with AI/ML systems in a venture-backed startup or tech firm, and hands-on experience with Python, LLMs, and modern AI toolchains.

Qualifications

• 4+ years of experience as a software engineer with AI/ML exposure.
• Experience taking features from ideation to production.

Responsibilities

• Own projects and features from conception to production.

Skills

Software engineering

AI/ML systems

Startup experience

Tools

Python

LLMs

agent frameworks

RAG pipelines

vector databases

FastAPI

Postgres

Elasticsearch

Job description

At a Glance

Capsa is an AI platform that accelerates due diligence and deepens insights for Private Equity funds. We are hiring Staff / Senior AI Engineers who are comfortable building and improving our AI agents and pushing the boundaries of what's possible with LLMs.

Details:

• Role: AI Engineer
• Location: London, UK (Hybrid, In-Person 4 days a week)
• Experience: Required: 4+ years
• Visa: Unfortunately, we don't sponsor visas yet. You must have the right to work in the UK.

About Capsa AI

At Capsa, we’re on a mission to transform how private capital firms source, analyse, and win deals. Our AI operating system accelerates due diligence, unlocks deeper insights, and helps funds focus on what matters — creating value.

We’re lean, ambitious, and obsessed with building a category-defining company. In just 12 months, we’ve grown ARR by 15x, achieved product–market fit with leading multi-billion-dollar PE firms, and expanded across the US, UK, and Europe. Backed by top VCs and senior PE execs from Warburg Pincus, KKR, and Goldman Sachs, we’re just getting started.

The Role

A senior AI engineer at Capsa is expected to own projects and features from conception to production, focusing on our core AI capabilities and agent infrastructure.

Key responsibilities include:

• Improving our agent's capabilities - design and implement new features that endow our agent with human-level investment expertise.
• Designing and optimising prompts, agent architectures, and reasoning chains to maximise output quality and reliability.
• Evaluating and integrating new models, techniques, and research to keep our AI capabilities at the cutting edge.
• Improving connectivity - integrate and incorporate additional data sources into our agent loop, increasing the depth and breadth of the analyses that can be performed.
• Maintaining high code quality - uphold rigorous standards across our codebase, ensuring tech debt doesn't impede our velocity.

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

As an early stage startup, working at Capsa will be hard work, it will be messy and at times it will be stressful. However, you will:

• Work directly with our founding team.
• Participate in the upside of an ultra-growth venture.
• Shape the company's vision and will have a direct impact on its success.
• Have the opportunity for fast career growth.
• Enjoy yourself!

Apply if

You’ll likely be a great fit if most of the following describe you:

• You have 4+ years of experience as a software engineer with significant exposure to AI/ML systems in a venture backed startup or top tech firm.
• You have taken entire products or features from ideation to production and you've measured their impact.
• You have experience with the following technologies (or similar): Python, LLMs (OpenAI, Anthropic, open-source models), agent frameworks, RAG pipelines, vector databases, FastAPI, Postgres, ElasticSearch
• You enjoy diving deep into the domain, understanding the problem, and focusing on delivering value to the customer.
• You thrive in a fast paced environment.

Additional Perks

Alongside the core role and growth opportunity, we also offer:

• Private healthcare insurance.
• One month per year remote working.
• Budget for setting up your Home-Office.