Principal AI Engineer

Harrington Starr; Boston (MA); On-site; USD 170,000 - 250,000; Full time

Job summary

Harrington Starr is seeking a Principal AI Engineer to shape the next generation of an AI-first platform for capital markets. You will lead hands-on engineering, influence architecture and deliver AI-powered products while remaining deeply involved in implementation.

The role combines technical leadership with architecture direction, mentoring, and ownership of high-impact AI initiatives in a fast-paced environment.

Qualifications

• Experience building and deploying production AI systems at scale.
• Strong background with RAG, AI agents and modern AI frameworks.
• Experience with vector databases, cloud platforms and scalable distributed systems.
• Proven track record of leading complex AI projects to production.

Responsibilities

• Design, build and deploy production-grade AI applications.
• Architect scalable RAG pipelines, agentic workflows and LLM-powered services.
• Build reliable AI APIs and backend services using Python.
• Drive model evaluation, prompt optimisation and AI system performance.
• Partner with engineering leadership on architecture and technical strategy.
• Mentor engineers and establish best practices across the AI function.

Skills

Production AI

LLMs

RAG pipelines

AI agents

Vector databases

Cloud platforms

Distributed systems

Python

Model evaluation

Job description

I'm working with a well-funded capital markets technology business that's building an AI-first platform to solve complex problems across financial services. They're looking to hire a Principal AI Engineer to help shape the next generation of their AI capability.

This is a hands-on technical leadership role for someone who has built and deployed production AI systems at scale. You'll have significant influence over architecture, technical direction and the delivery of AI-powered products, while remaining deeply involved in engineering.

The role

• Design, build and deploy production-grade AI applications.
• Architect scalable RAG pipelines, agentic workflows and LLM-powered services.
• Build reliable AI APIs and backend services using Python.
• Drive model evaluation, prompt optimisation and AI system performance.
• Partner with engineering leadership on architecture and technical strategy.
• Mentor engineers and help establish best practices across the AI function.

What they're looking for

• Experience building and deploying production LLM applications.
• Strong background with RAG, AI agents and modern AI frameworks.
• Experience with vector databases, cloud platforms and scalable distributed systems.
• A track record of owning complex technical projects from concept through production.
• Previous experience within financial services or capital markets

Why it's worth exploring

• Join a business building AI at the core of its product rather than as an add-on.
• High levels of ownership and influence over technical direction.
• Solve challenging engineering problems with modern AI technologies.
• Work alongside experienced engineering leaders in a fast-paced environment.
• Competitive compensation, bonus and equity.

If you're interested in hearing more, get in touch for a confidential conversation.