Senior Full-Stack AI Agent Engineer (Python/React) Hybrid

Worky; Manchester; Hybrid; GBP 70,000 - 110,000; Full time

Benefits offered by this job

Hybrid work options

Professional development

Collaborative culture

Job summary

Mercer UK is seeking a talented senior full‑stack developer to lead the AI Product team for the Pensions AI Assistant. You will own end‑to‑end development across backend, frontend and deployment, working with the lead Data Science/AI engineer and reporting to the Head of AI Product.

Hybrid or office-based work arrangements are supported. You will develop reliable, trustworthy systems with a strong emphasis on quality, performance and security, while gaining domain knowledge in pensions and

Qualifications

• Proven experience as a senior full-stack developer delivering production software.
• Strong backend engineering in Python (APIs).
• Solid frontend experience with React and TypeScript.
• Hands-on experience deploying and running applications on Kubernetes.
• Experience building AI/LLM-enabled products for customer-facing use.
• Collaborative, self-starting and able to drive work forward in a small team.

Responsibilities

• Lead full-stack development and maintenance of the AI Assistant tech stack across backend (Python), frontend (React/Next.js), and deployment (OSS2/Kubernetes).
• Design, code, test, and ensure performance, security and quality across the app lifecycle.
• Improve AI agent reliability, trust and safety for customer use.
• Participate in technical design, peer review, and maintain engineering practices.
• Create and maintain documentation; liaison with IT and Marsh Tech as needed.
• Diagnose issues, resolve problems, and propose product improvements.
• Support AI change initiatives across DC with ad-hoc projects; flexible work as needed.

Skills

Senior full-stack

Python backend

React/TypeScript

Kubernetes

AI/LLM experience

Self-starter

Team collaboration

Tools

Docker

MongoDB

Next.js

OSS2

Job description

Mercer UK is seeking a talented senior full‑stack developer to lead the AI Product team for the Pensions AI Assistant. You will own end‑to‑end development across backend, frontend and deployment, working with the lead Data Science/AI engineer and reporting to the Head of AI Product.

Hybrid or office-based work arrangements are supported. You will develop reliable, trustworthy systems with a strong emphasis on quality, performance and security, while gaining domain knowledge in pensions and