Principal AI Engineer

Company Overview

LSEG (London Stock Exchange Group) is a diversified global financial markets infrastructure and data business dedicated to excellence and open‑access partners. With a heritage of 300+ years, LSEG enables businesses to fund innovation, manage risk and create jobs worldwide.

The Principal AI Engineer is a senior technical expert responsible for designing, developing, and delivering high‑quality software solutions, with a focus on AI technologies such as prompt engineering and large language models (LLMs). The role emphasizes deep technical proficiency, innovation, and hands‑on development across scalable, secure, and performance‑critical systems.

• Software Development
  • Design and implement complex, scalable, and secure applications.
  • Write clean, efficient, and maintainable code in Java, Python, and other high‑level languages.
• Technical Expertise
  • Provide architectural guidance and ensure adherence to best practices.
  • Optimize system performance and troubleshoot critical issues.
• AI Development
  • Develop and refine prompt engineering strategies for LLM‑based applications.
  • Integrate and optimise Large Language Models (LLMs) into products and workflows.
  • Collaborate with AI teams to improve model performance and user experience.
• Innovation & Research
  • Stay current with emerging technologies, frameworks, and AI advancements.
  • Prototype and evaluate new tools and methodologies for adoption.
  • Work closely with product managers, QA, and other developers to deliver high‑quality solutions.
  • Participate in code reviews and contribute to technical documentation.
• Process & Quality
  • Advocate for automation, testing, and continuous integration practices.
  • Ensure compliance with security and regulatory standards.

• Proven experience in software development with at least a year in AI Development.
• Extensive experience in system architecture and delivering complex projects.
• Strong technical background in Java, Python, and other high‑level programming languages.
• Expertise in designing scalable and secure systems.
• Hands‑on experience with AI tools and frameworks, including:
• Prompt Engineering for LLMs (e.g., OpenAI GPT, Anthropic Claude).
• Model fine‑tuning and deployment.
• AI integration into enterprise applications.
• Prompt management tools (Langfuse).
• Knowledge of vector databases, embeddings, and retrieval‑augmented generation (RAG).
• Experience with cloud platforms (AWS, Azure, GCP).
• Familiarity with CI/CD pipelines and modern development tools.

• Healthcare and retirement planning.
• Paid volunteering days and wellbeing initiatives.
• Opportunities for professional growth and career advancement.

LSEG is a proud equal opportunities employer. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, gender identity, gender expression, age, marital status, veteran status, pregnancy or disability, or any other basis protected under applicable law. We accommodate applicants’ and employees’ religious practices and mental health or physical disability needs in compliance with applicable law.