Senior AI Engineer - Legal AI

About 9fin 9fin is the AI platform powering global debt markets — the world’s largest asset class at over $145 trillion. Debt markets are vast, global, and mission-critical, yet still run on fragmented data, PDFs, and manual workflows. 9fin replaces this broken infrastructure with a single platform that centralises proprietary credit data, deep analysis, and high-value workflows across global markets. Today, 9fin powers teams at 300+ blue-chip institutions worldwide, including global banks, asset managers, private equity firms, law firms, and advisors. The business is scaling at exceptional speed, with rapid expansion in the US and best-in-class retention driven by deep workflow adoption. We’re at a defining inflection point. With proven product-market fit and strong, global market pull, 9fin is accelerating toward becoming the category-defining platform for debt markets worldwide. THE OPPORTUNITY The Data Science team is growing at 9fin! We are doing world-class work with groundbreaking technologies to build data-driven products using machine learning, computer vision, natural language processing, speech and audio, and knowledge/data mining. We are looking for a Senior AI Engineer to accelerate our application of AI across teams and products. Come and join us, you will get to build large-scale AI powered systems, learn and apply the latest techniques, and work alongside other great researchers and engineers! Every day is different, but here's an example of the kind of things you'll work on: - Design and build generative AI applications tailored to complex financial and legal workflows, leveraging state-of-the-art models to deliver innovative, practical solutions that streamline decision-making and unlock new efficiencies. - Drive end to end model development lifecycle, leading the team in best practices, ensuring reproducible research and well managed model delivery/deployment. - Collaborate cross functionally to share diverse ideas, understand business problems, and elevate/mentor your teammates. - Translate complex problems into well-defined scoped bets in an internal startup style environment, dynamic and fast-paced. - Learn and apply ground-breaking research and approaches in advanced topics, iterating improvements with a fail fast mentality. - Be a proactive sharer of compelling ideas/work to the rest of the team and organisation. We want you to help lead/push the adoption of AI throughout 9fin. WHAT MAKES THIS ROLE DIFFERENT This role is focused on converting complex financial and legal documents into structured, reliable data. While experience with chatbots, retrieval systems, and general-purpose AI applications is valuable, the core challenge is building systems that can accurately understand legal documentation and extract the information that powers financial analysis and workflow automation. ABOUT YOU This role will be a great fit if you: - Legal Document Intelligence: Deep experience working with complex legal and financial documents, including bond offering memoranda, credit agreements, indentures, court filings, and related transaction documentation. - Information Extraction: Expertise in extracting structured data from long, complex documents, including financial terms, covenant provisions, definitions, parties, dates, thresholds, baskets, ratios, and transaction mechanics. - Document Understanding & NLP: Strong understanding of document structure, section hierarchy, cross-references, defined terms, tables, exhibits, and other patterns common in legal and financial documentation. - LLMs for Structured Extraction: Experience applying LLMs to high-precision extraction tasks, including schema-driven extraction, citation grounding, validation, and confidence scoring. - Data Quality & Validation Systems: Ability to design review, verification, and reconciliation workflows that ensure extracted data is accurate, consistent, and auditable. - Training Data & Annotation: Experience building labelled datasets, annotation frameworks, synthetic data generation, and evaluation sets for document extraction tasks. - Retrieval & Context Engineering: Strong understanding of chunking, document segmentation, retrieval, and context construction for long-document reasoning and extraction workflows. - Financial & Legal Domain Knowledge: Familiarity with leveraged finance, debt capital markets, credit agreements, covenant packages, bond documentation, restructuring processes, and related legal concepts. - Production ML Engineering: Ability to build and operate extraction pipelines, evaluation systems, model-serving infrastructure, and monitoring for production AI workflows. - Strong proficiency in Python for production ready delivery. - Experience working in the full model lifecycle (including experimentation, training, testing, monitoring, and deployment). We are data centric and love our evals! - You have a strong product focus with a desire to understand the end-to-end impact of your solutions for our end users. - Good knowledge of AWS’s AI infrastructure. BENEFITS We’re a scaling start up, and we enjoy sharing our success, when the company succeeds, we always reinvest that in our people. We also offer huge amounts of responsibility, an abundance of opportunity for growth and a platform to truly excel. Financial & Insurance - Competitive Salary (our salary bands are benchmarked at the top end of the market) - Equity - Pension (your minimum contributions are 4% with 9fin matching up to 7%) - Private Medical Insurance - Paid sick leave with Income Protection for long periods of illness - Group Life Assurance  - Season Ticket Loan & Cycle to Work schemes Time off  - 25 holiday days per year - Local public holidays (with the ability to exchange them for alternative days) - Hybrid working model, to allow you the flexibility to decide how, where and when you do your best work - Work abroad for up to 3 months a year - 1 month paid sabbatical after 5 years of service - Enhanced parental leave & flexible working arrangements available Training & Culture  - Professional learning and development budget - AI experimentation budget of £800 (UK) per employee to trial AI tools - Quarterly team socials - Summer and Winter company social events 9fin is an equal opportunities employer At 9fin we are dedicated to building and promoting a fair and inclusive workplace where everyone can reach their full potential and truly belong. We recognize that building diverse teams enables a more creative and productive environment. If you’re excited about this role but your experience doesn’t perfectly align with the job description, we encourage you to apply anyway. You might just be who we’re looking for — either for this role, or perhaps another.