Job Overview:

The Senior Applications Developer is a senior technical contributor responsible for designing, developing, and delivering modern enterprise applications that simplify business processes, improve user experiences, and increase operational efficiency.

The role combines strong full-stack application development using the MERN stack — MongoDB, Express.js, React, and Node.js — with workflow engineering, API and system integration, cloud technologies, and emerging agentic AI capabilities.

The ideal candidate is an experienced software engineer who can translate complex business requirements into intuitive, scalable, secure, and maintainable applications. This individual will own solutions across the application lifecycle—from architecture and user experience through business logic, workflow orchestration, integrations, data, deployment, monitoring, and continuous improvement.

A key focus of the role will be designing applications that orchestrate work across users, systems, data, APIs, automation, and increasingly AI agents and intelligent services. The Senior Applications Developer will help establish patterns for incorporating generative AI and agentic technologies into enterprise applications where they deliver measurable business value.

Key Responsibilities

• Lead the design and development of enterprise-grade applications from concept through production, supporting business, analytics, automation, and data-driven use cases.

• Design, build, and maintain full-stack applications using the MERN stack: MongoDB, Express.js, React, Node.js, JavaScript, and TypeScript.

• Develop modern, responsive, accessible, and high-performing user experiences using React and contemporary front-end development patterns.

• Design application architecture spanning user interfaces, business logic, workflows, APIs, integrations, data services, cloud components, and AI-enabled capabilities.

• Design and implement application workflows that coordinate activities across users, business rules, approvals, APIs, data, automated processes, and external systems.

• Build secure, reusable, and well-documented REST APIs, microservices, webhooks, and integration services using Node.js/Express and, where appropriate, Python/FastAPI.

• Design applications for performance, scalability, reliability, resiliency, maintainability, and operational efficiency, identifying bottlenecks and continuously optimizing application performance.

• Work with SQL and NoSQL databases, including MongoDB and enterprise data platforms, designing effective schemas, queries, data access patterns, and integrations.

• Develop event-driven and asynchronous application capabilities where appropriate using queues, messaging, background processing, and resilient integration patterns.

• Evaluate opportunities to incorporate generative AI, intelligent agents, and agentic workflows into applications and business processes.

• Determine the appropriate technical approach for a business problem across custom application development, APIs, automation, workflow technologies, cloud services, data platforms, and AI/agentic technologies rather than defaulting to a single technology.

• Troubleshoot complex production issues across application, integration, workflow, data, and infrastructure layers.

• Contribute to architectural decisions and establish reusable components, development standards, application patterns, and engineering best practices.

• Conduct code reviews, provide technical guidance, and mentor developers to improve engineering quality and consistency.

• Partner closely with product owners, analysts, designers, business stakeholders, data teams, and technology teams to translate business needs into scalable technical solutions.

• Ensure applications comply with enterprise requirements for security, privacy, resiliency, testing, documentation, governance, and production support.

Basic Qualifications

• Bachelor’s degree in Computer Science, Software Engineering, Information Systems, or a related technical discipline, or equivalent relevant professional experience.

• 5+ years of professional software engineering or application development experience, including experience delivering production applications end-to-end.

• Strong professional experience developing full-stack applications using the MERN stack, including:

  • MongoDB
  • Express.js
  • React
  • Node.js
  • JavaScript and/or TypeScript

• Experience designing and implementing business workflows, application processes, workflow orchestration, or automation solutions involving multiple users, systems, integrations, or decision points.

• Strong knowledge of REST APIs, API-first architecture, JSON, webhooks, authentication, and enterprise integrations.

• Experience with both SQL and NoSQL databases, including data modeling, query design, and application data access patterns.

• Experience designing applications for scalability, performance, resiliency, maintainability, and reliability.

• Experience with asynchronous programming, event-driven architectures, background processing, or distributed application patterns.

• Experience with Git, automated testing, CI/CD pipelines, and modern Agile software development practices.

• Experience deploying applications using containers such as Docker and familiarity with Kubernetes or comparable orchestration technologies.

• Demonstrated ability to independently translate complex business requirements into effective technical designs and production-ready applications.

• Strong troubleshooting, analytical thinking, systems thinking, and problem-solving capabilities.

• Experience participating in technical design discussions, code reviews, and development standards.

• Strong communication skills and demonstrated ability to collaborate with technical and non-technical stakeholders across global and cross-functional teams.

• Professional English proficiency.

Preferred Qualifications

• Experience developing APIs, AI services, automation, or data-intensive applications using Python and FastAPI.

• Experience designing applications where AI agents securely interact with enterprise APIs, data, workflows, and business systems.

• Experience using AI-assisted engineering environments or agentic coding tools to improve software development productivity.

• Skills and Attributes

• Strong product and systems-thinking mindset, with the ability to understand not only individual application components but how users, workflows, data, systems, and technologies interact end-to-end.

• Ability to balance speed of delivery with security, scalability, reliability, and long-term maintainability.

• Curiosity and enthusiasm for experimenting with new technologies and translating emerging capabilities into practical business solutions.

• Self-starter who can independently drive complex technical initiatives while collaborating effectively with broader teams.

• Ability to mentor other developers and elevate engineering practices across the team.

• Strong stakeholder management and relationship-building skills, including the ability to influence technical decisions without direct authority.

• Comfortable operating in a fast-paced environment with changing priorities and evolving technology.

• Strong attention to detail and a user-centric approach to application development.

Oliver Wyman is a business of Marsh (NYSE: MRSH), 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 oliverwyman.com, or follow us on LinkedIn and X.

Marsh is committed to creating 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, or any other characteristic protected by applicable law.

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.