Senior AI Engineer - Knowledge Graphs in London

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.

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.

This role is focused on building systems of persistent knowledge: representing entities, relationships, and events that evolve over time. While experience with LLMs, retrieval systems, and recommendation engines is valuable, the primary challenge is creating and maintaining the knowledge graph that powers intelligence, discovery, and workflow automation across the platform.

About You: This role will be a great fit if you:

• Knowledge Graph Design & Ontology Modelling: Expertise in modelling complex domains as interconnected graphs, covering companies, sponsors, lenders, law firms, financial instruments, transactions, documents, events, and their relationships.
• Entity Resolution & Canonical Data Modelling: Strong experience with identity resolution, record linkage, alias handling, and entity disambiguation across fragmented and noisy financial datasets.
• Relationship Extraction & Knowledge Acquisition: Proven ability to extract structured entities, events, and relationships from unstructured sources such as filings, legal documents, news, transcripts, and research content.
• Graph Search & Retrieval Systems: Experience building graph-native retrieval and exploration capabilities that surface relationships, ownership structures, transaction histories, and connected entities.
• Similarity, Peer & Precedent Discovery: Ability to design systems that identify comparable companies, relevant precedents, analogous situations, and related transactions using both graph structure and content signals.
• Graph Machine Learning: Familiarity with graph embeddings, node similarity, clustering, community detection, link prediction, and relationship scoring techniques.
• Production Data & Platform Engineering: Experience building and operating entity stores, graph pipelines, knowledge infrastructure, and low-latency serving systems at production scale.
• Strong proficiency in Python for production ready delivery.
• Experience working in the full model lifecycle (including experimentation, training, testing, monitoring, and deployment).
• 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.

• 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
• 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.