Principle AI / ML Engineer

AI Principal Engineer

Competitive salary + equity

London, Marylebone (Hybrid / Onsite)

Do you thrive on transforming ambitious AI ideas into elegant, scalable systems that solve real-world problems?

The focus has shifted heavily toward Agentic AI—systems that use reasoning loops to execute complex business processes independently. This role is currently a major "Force Multiplier," as one engineer building an effective agentic fleet can automate the output of an entire traditional department.Are you excited by the opportunity to shape how an entire industry interacts with conversational AI Join us at the forefront of the largest and most opportunity-rich markets in the world as we build a category-defining startup from the ground up. This is a rare chance to help modernise a global industry ready for transformation, where your work won’t just ship features, it will redefine how millions of professionals plan, build, and operate.1

If you thrive at the intersection of AI, engineering, and product experience, we’d love to hear from you.

About Prolo

At Prolo, we’re reinventing procurement for the construction industry using AI. Our conversational platform allows customers to source materials effortlessly across chat, email, and phone, saving time and money with zero setup.

We’re a small, ambitious team that moves fast, trusts each other, and enjoys building technology that makes a real difference in a traditionally underserved industry.

The Role

The Principal AI Engineer is a senior technical expert responsible for designing, developing, and delivering high-quality software solutions.

This role emphasizes deep technical proficiency, innovation, and hands-on development, with a specific focus on designing and deploying sophisticated Agentic AI systems. The ideal candidate will serve as a technical authority, proving concepts with the latest AI technology or practices in the form of a spike or proof of concept.

What You’ll Be Doing

Agentic AI & LLM Engineering

• Agentic Workflow Design: Develop multi-agent systems using frameworks like LangGraph or CrewAI for autonomous research and automated coding.
• Advanced RAG & Memory: Build sophisticated Retrieval-Augmented Generation (RAG) pipelines for long-term model memory.
• Model Optimization: Fine-tune open-source models (Llama 3/4) to reduce latency and costs.
• LLMOps: Implement automated "Evals" to measure hallucination rates and tool-calling accuracy.
• Tool Integration: Use Model Context Protocol (MCP) to connect agents to internal databases and APIs.
• Develop and refine engineering strategies for LLM-based applications.
• Collaborate with AI teams to improve model performance and user experience.

Software Development & Technical Leadership

• Design and implement complex, scalable, and secure applications.
• Develop the architecture and ensure adherence to best practices.
• Optimize system performance and troubleshoot critical issues.
• Write clean, efficient, and maintainable code in Python, Java, and other high-level languages.
• Advocate for automation, testing, and continuous integration practices.

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.

Required Skills & Experience

• Languages: Expert Python proficiency for production-grade AI development; proficiency in TypeScript.
• Frameworks: Hands-on experience using LangChain/LangGraph, LlamaIndex, PyTorch, and FastAPI
• Infrastructure: Experience with AWS Bedrock/SageMaker; Docker/Kubernetes for scaling agent instances.
• Proven experience building Retrieval-Augmented Generation (RAG) systems; Graph-RAG experience is a plus.
• Practical experience with model adaptation techniques, including prompting, fine-tuning, instruction tuning, or knowledge distillation.
• Solid understanding of evaluation and experimentation for generative AI, focused on correctness, faithfulness, and robustness, aligning with LLMOps practices.
• Demonstrable experience owning technical design and delivery of complex AI, ML, or data-driven systems in production environments.
• Experience operating as a senior AI engineer or technical lead, balancing experimentation with production delivery and communicating effectively across teams.

What’s in It for You

• Real ownership of a core, customer-facing AI product
• The opportunity to work on cutting-edge conversational AI and Agentic Systems.
• Close collaboration with a talented, ambitious founding team
• Competitive salary and meaningful equity
• A culture built on pace, trust, and impact
• The chance to help build a product customers genuinely love

Apply today and help us build the future of construction at Prolo.

Prolo Ltd is committed to creating an inclusive and diverse workplace. We welcome applicants from all backgrounds.

NO AGENCIES PLEASE