Founding AI Engineer — Legal BD Platform (Equity)

Rainmaker; Greater London; On-site; GBP 90,000 - 140,000; Full time

Benefits offered by this job

Equity

Founding team

Job summary

Rainmaker is seeking its first dedicated AI Engineer to own the intelligence layer of the product, including retrieval over legal news, deals, and firm data. You will shape how we evaluate, what we run in-house, and how models behave reliably in production.

This founding hire reports to the CTO and joins a hands-on multi-disciplinary engineering team with meaningful equity. You will build and refine retrieval, grounding, and agentic features, ensuring precision and traceability while avoiding

Qualifications

• 5–8 years in software engineering, with at least two spent building LLM-backed systems that real users depend on.
• Deep retrieval experience: built RAG systems that worked and can explain why first versions failed.
• Rigour about evaluation with dedicated eval infrastructure.
• Strong grounding in Python and TypeScript; comfortable with AWS in production environments.
• Fluency across model landscapes and related tooling to pick reliable options.
• Comfort with ambiguity and owning a domain independently for a while.
• Directness: raise issues early and base decisions on data.

Responsibilities

• Own end-to-end retrieval: chunking, embedding, indexing, hybrid and re-ranked search over legal news and deal data.
• Build entity resolution across sources so entities mean the same thing everywhere.
• Ensure grounding and citation are intrinsic, traceable to sources.
• Define where retrieval ends and structured queries begin; avoid unnecessary model use.
• Develop LLM-backed features and guided-question loops for the BD Centre; safeguard against fabrications.
• Design safe agent/tool-use flows and maintain versioned, testable prompt architecture.
• Build the eval harness and measure quality metrics; monitor hallucinations, latency and cost per interaction.
• Work with data pipelines to ingest legal content and turn it into structured records; improve precision/recall over time.
• Ship production code in a TS/Python stack on AWS; own infra costs, latency and reliability.
• Provide non-engineers with tools to inspect and improve model output without coding.
• Advise product on feasibility, cost and research scope; set engineering standards for AI features.

Skills

Software engineering

LLM-backed systems

Retrieval / RAG

Evaluation infrastructure

Python

TypeScript

AWS production systems

Model landscape fluency

Directness

Job description

Rainmaker is seeking its first dedicated AI Engineer to own the intelligence layer of the product, including retrieval over legal news, deals, and firm data. You will shape how we evaluate, what we run in-house, and how models behave reliably in production.

This founding hire reports to the CTO and joins a hands-on multi-disciplinary engineering team with meaningful equity. You will build and refine retrieval, grounding, and agentic features, ensuring precision and traceability while avoiding