Senior Full Stack Engineer - Oliver Wyman

Marsh; Dublin; Hybrid; EUR 90,000 - 140,000; Full time

Job summary

Marsh is seeking a Senior Full-Stack Engineer, Generative AI, to design, build, and operate enterprise-grade AI-enabled web applications across the stack in Dublin. You will work on LLM-integrated services, ensuring security, reliability, and maintainability while delivering production-ready systems.

You will contribute to architectural decisions, collaborate with product and security teams, and champion modern engineering practices in a hybrid work environment that combines office and remote

Qualifications

• 6+ years of professional software engineering experience, including building and operating production systems.
• Hands-on experience working with Large Language Models (LLMs) in applied or production contexts.
• Strong proficiency in a modern frontend framework, ideally React with TypeScript.
• Deep hands-on experience with NodeJS / NestJS and/or Python (FastAPI or Django).
• Strong understanding of API design, distributed systems, and service-oriented architectures.
• Proven experience deploying, operating, and supporting systems in cloud environments.
• Experience working in Agile delivery teams and collaborating across disciplines.
• Strong communication skills, with the ability to explain technical concepts to a range of audiences.
• Sound engineering judgment and a pragmatic, delivery-focused mindset.

Responsibilities

• Lead the technical design and delivery of complex, AI-enabled features or services.
• Design, build, and evolve full-stack applications using modern frontend and backend frameworks.
• Build and maintain robust, high-performance APIs using NestJS / NodeJS or FastAPI / Python.
• Integrate Large Language Model (LLM) capabilities into production systems, selecting appropriate patterns, tools, and architectures.
• Guide the evolution of proofs of concept into production-ready, scalable solutions within enterprise constraints.
• Own technical solutions end-to-end, including design, implementation, deployment, and operational readiness.
• Make sound engineering decisions that balance security, scalability, reliability, maintainability, and testability.
• Act as a hands-on engineer: write production code, review code, and contribute to testing and observability.
• Champion strong engineering practices, including code quality, testing, CI/CD, and documentation.
• Identify opportunities for reuse and contribute to shared components, patterns, and standards.
• Collaborate closely with product, architecture, security, and platform teams in an Agile delivery environment.
• Provide technical guidance and mentorship to other engineers through design discussions and example.
• Contribute to continuous improvement of engineering practices within the team or domain.

Skills

LLMs experience

React with TS

NodeJS/NestJS

Python (FastAPI)

Cloud infrastructure

Agile delivery

Strong communication

Tools

NestJS

NodeJS

FastAPI

Python

React

TypeScript

Job description

What can you expect

Oliver Wyman Tech is building rapid AI delivery pods, with teams based in Dublin, to address some of the most critical business challenges across our global enterprise. You will join a high-impact team operating as an AI acceleration engine — rapidly prototyping, validating, and deploying scalable enterprise solutions that move from idea to measurable impact in weeks, not months.

What can you expect

Oliver Wyman Tech is building rapid AI delivery pods, with teams based in Dublin, to address some of the most critical business challenges across our global enterprise. Co-located with the Marsh Innovation Hub and embedded within a regional agile delivery pod, this is a unique opportunity to work in a fast-paced, highly visible environment where innovation translates quickly from concept to real-world value. This role offers the opportunity to help shape the next generation of AI-enabled products, intelligent workflows, and decision systems We are seeking an experienced Senior Full-Stack Engineer, Generative AI to design, build, and operate enterprise-grade AI-enabled solutions across our technology organization. This role is for a senior individual contributor who combines strong hands-on engineering skills with sound technical judgment and the ability to raise the quality of delivery within a team or domain. You will work on complex, real-world problems, developing AI-enabled web applications across the full stack using modern frontend and backend technologies, Large Language Models (LLMs), and cloud infrastructure. You will play a key role in evolving solutions from early proof of concept through to scalable, production-ready systems used by internal and external stakeholders. In this role, you are relied upon to ensure solutions meet enterprise standards for security, reliability, scalability, maintainability, and testability, and to help teams apply generative AI responsibly and effectively in production environments.

What we will rely on you to do

• Lead the technical design and delivery of complex, AI-enabled features or services.
• Design, build, and evolve full-stack applications using modern frontend and backend frameworks.
• Build and maintain robust, high-performance APIs using NestJS / NodeJS or FastAPI / Python.
• Integrate Large Language Model (LLM) capabilities into production systems, selecting appropriate patterns, tools, and architectures.
• Guide the evolution of proofs of concept into production-ready, scalable solutions within enterprise constraints.
• Own technical solutions end-to-end, including design, implementation, deployment, and operational readiness.
• Make sound engineering decisions that balance security, scalability, reliability, maintainability, and testability.
• Act as a hands-on engineer: write production code, review code, and contribute to testing and observability.
• Champion strong engineering practices, including code quality, testing, CI/CD, and documentation.
• Identify opportunities for reuse and contribute to shared components, patterns, and standards.
• Collaborate closely with product, architecture, security, and platform teams in an Agile delivery environment.
• Provide technical guidance and mentorship to other engineers through design discussions and example.
• Contribute to continuous improvement of engineering practices within the team or domain.

What you need to have

• 6+ years of professional software engineering experience, including building and operating production systems.
• Hands-on experience working with Large Language Models (LLMs) in applied or production contexts.
• Strong proficiency in a modern frontend framework, ideally React with TypeScript.
• Deep hands-on experience with NodeJS / NestJS and/or Python (FastAPI or Django).
• Strong understanding of API design, distributed systems, and service-oriented architectures.
• Proven experience deploying, operating, and supporting systems in cloud environments.
• Experience working in Agile delivery teams and collaborating across disciplines.
• Strong communication skills, with the ability to explain technical concepts to a range of audiences.
• Sound engineering judgment and a pragmatic, delivery-focused mindset.

What makes you stand out

We do not expect experience in all areas below. Strong senior engineers typically demonstrate depth in some areas and familiarity with others.

• Experience designing or implementing Retrieval-Augmented Generation (RAG) systems in applied or production contexts.
• Experience evaluating and selecting GenAI frameworks or tools (e.g., LangChain, LangGraph, LlamaIndex, CrewAI) based on problem context.
• Experience with AI agents, orchestration patterns, or workflow-based AI systems, including understanding when such approaches are appropriate.
• Familiarity with prompt engineering, evaluation techniques, and guardrails for LLM-based systems.
• Experience with cloud-native architectures, CI/CD pipelines, and infrastructure-as-code.
• Understanding of security-driven design and how to address common application or platform vulnerabilities in enterprise systems.

Why join our team

• The opportunity to build and influence enterprise-scale generative AI solutions.
• Meaningful technical ownership without people-management responsibilities.
• A collaborative, inclusive engineering culture with strong technical peers.
• Ongoing learning and professional development opportunities.
• The scale and stability of a global organization combined with modern engineering practices.
• Competitive compensation and benefits aligned with local market practices.

#MMCIC Marsh (NYSE: MRSH) is a global leader in risk, reinsurance and capital, people and investments, and management consulting, advising clients in 130 countries. With annual revenue of over $27 billion and more than 95,000 colleagues, Marsh helps build the confidence to thrive through the power of perspective. For more information, visit marsh.com, or follow us on LinkedIn and X. Marsh is committed to embracing a diverse, inclusive and flexible work environment. We aim to attract and retain the best people and embrace diversity of age, background, disability, ethnic origin, family duties, gender orientation or expression, marital status, nationality, parental status, personal or social status, political affiliation, race, religion and beliefs, sex/gender, sexual orientation or expression, skin color, Traveller community, or any other characteristic protected by applicable law. We are an equal opportunities employer. We are committed to providing reasonable support to any candidate with a disability/health condition to allow them to fully participate in the recruitment process. We welcome candidates to contact us at [e-mail] to discuss any specific needs. Marsh is committed to hybrid work, which includes the flexibility of working remotely and the collaboration, connections and professional development benefits of working together in the office. All Marsh colleagues are expected to be in their local office or working onsite with clients at least three days per week. Office-based teams will identify at least one anchor day per week on which their full team will be together in person.

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