Hybrid Senior Software Engineer – Python, ML, AI Systems

at Cornspring

• Job title: Senior Software Engineer – Python, ML, AI Systems
• Job type: Full Time
• Experience level: Senior
• Salary: Not specified
• Degree requirement: Bachelor's Degree
• Tech skills: Azure, Python
• Location requirements: Hybrid, London, United Kingdom

About the role

• Senior Software Engineer developing scalable AI-driven systems for a FinTech startup. Leading technical architecture and implementation of advanced machine learning solutions in a hybrid work environment.

Responsibilities

• Design, build, and optimise scalable backend systems in Azure, utilising Python, containers, FastAPI, and modern architectural approaches.
• Take complete ownership of services throughout their lifecycle: from initial concept and design through to deployment, monitoring, and ongoing iteration.
• Enhance performance and reliability through refactoring, algorithmic improvements, asynchronous processing, and strategic caching.
• Work at pace by prototyping rapidly, evaluating outcomes, scaling up successful approaches, and quickly adapting or pivoting when necessary.
• Collaborate closely with product and data teams to transform intricate financial and AI requirements into robust, production-ready features.
• Design and implement LLM-powered features using both SaaS models and locally hosted models.
• Build and evolve Retrieval-Augmented Generation (RAG) pipelines for both structured and unstructured financial and accounting data.
• Leverage HuggingFace, vLLM, prompt engineering, and model orchestration frameworks to deliver advanced AI solutions.
• Implement robust evaluation, testing, and monitoring processes for LLM outputs, prioritising correctness, determinism, latency, and cost efficiency.
• Optimise model selection, inference strategies, and prompting techniques to ensure reliable performance within real-world production constraints.
• Contribute to the development of internal AI tooling and workflows, driving measurable improvements in developer productivity and overall product quality.
• Contribute to engineering best practices and play an active role in shaping technical standards and architectural decisions.
• Work in close collaboration with engineering, product, and data teams to deliver secure, scalable, and well-designed solutions.
• Mentor fellow engineers by conducting code reviews, engaging in technical discussions, and providing practical examples.
• Champion lean and clean architecture to ensure maintainable code and uphold rigorous testing discipline.
• Drive ongoing improvements in system performance, scalability, and the overall developer experience.

Requirements

• Degree in Computer Science (or equivalent), with strong software engineering fundamentals.
• Significant hands-on experience as a software engineer, including senior-level ownership and decision-making.
• Strong experience building AI-driven systems, with particular depth in LLMs and applied ML (e.g. RAG, prompt engineering, model evaluation).
• Excellent Python skills and experience delivering production backend systems.
• Strong problem-solving, communication, and collaboration skills.
• A mindset oriented towards ownership, quality, and continuous learning.

Benefits

• Competitive salary and benefits, including private medical insurance, cash plan, life insurance, and income protection.
• Hybrid working: three days per week in our City of London office.
• An opportunity to work at the forefront of AI-driven finance, tackling genuinely complex and high-impact challenges.
• Hands-on exposure to advanced ML, LLM, and data technologies within real production systems.
• A collaborative, high-ownership startup environment offering exceptional learning opportunities.
• The chance to help shape the future of Family Office and Asset Management technology.