Senior React Developer – Data Products in London

Aon is looking for a Data Products Engineer to join our technology team, where you will be responsible for building and scaling the data infrastructure and APIs that support our market intelligence products, delivering valuable insights to clients through enterprise web applications. This is a hybrid role with the flexibility to work both virtually and from our Dublin office.

Aon is in the business of better decisions. At Aon, we shape decisions for the better to protect and enrich the lives of people around the world. As an organisation, we are united through trust as one inclusive team and we are passionate about helping our colleagues and clients succeed.

What the day will look like

• Design and develop modern APIs that serve both raw data and AI-generated insights to our suite of client‑facing web applications.
• Build and optimise performant data pipelines using Polars, FastAPI, and Python, ensuring fast response times and efficient memory usage.
• Collaborate closely with front end engineers, product managers, and machine learning engineers to deliver seamless, user‑focused features.
• Implement API‑first architecture practices, with careful attention to schema design, versioning, and documentation.
• Work across the AWS stack, deploying scalable services that power mission‑critical experiences for enterprise users.
• Contribute to system design decisions, database modelling, and service orchestration to ensure resilient, maintainable back end systems.
• Monitor and tune application performance, from query speeds to service latency and throughput.
• Support a culture of engineering excellence, code quality, and continuous improvement.

How this opportunity is different

This is a great opportunity for individuals passionate about building elegant, scalable, and performant back‑end systems, with a track record of delivering robust APIs that enable dynamic React front ends and unlock the full value of data and AI‑driven insights. Behind every insight we deliver is a fast, reliable, and intelligent API infrastructure—designed to serve curated data and machine‑generated intelligence in milliseconds. You’ll be working with a modern Python stack to build the systems that make this possible: robust data services, scalable APIs, and infrastructure that keeps up with demanding enterprise users.

Skills and experience that will lead to success

• Few years of professional software engineering experience, ideally in B2B or data product environments.
• Deep experience with Python, including libraries like Polars, PySpark, and frameworks such as FastAPI or Fastify and up‑to‑date with modern Python best practices, including tools such as Ruff, UV and PyEnv.
• Experience working on data‑heavy platforms or with AI/ML outputs exposed via APIs.
• Proficient in designing, building, and scaling RESTful APIs (GraphQL experience is a bonus).
• Strong knowledge of cloud infrastructure, especially the AWS stack (Lambda, ECS, S3, CloudWatch, etc.).
• Solid understanding of data performance trade‑offs—e.g. query optimization, memory use, parallelism.
• Familiarity with modern CI/CD pipelines, containerisation (Docker), and IaC tools like Terraform.
• Strong collaboration skills—able to partner with front end teams and product stakeholders to ship well‑integrated features.
• Comfortable in fast‑paced, high‑autonomy environments with a strong culture of accountability.

Nice to Have

• Familiarity with React and how front end teams consume and interact with back end services.
• Experience with the Databricks platform and ecosystem.
• Prior experience in a market intelligence, financial data, or analytics SaaS business.
• Working knowledge of SQL/NoSQL databases and data modelling in analytics contexts.
• Comfortable working with AI developer assistants (e.g. GitLab Copilot).

How we support our colleagues

In addition to our comprehensive benefits package, we encourage an inclusive workforce. Plus, our agile environment allows you to manage your wellbeing and work/life balance, ensuring you can be your best self at Aon. Furthermore, all colleagues enjoy two “Global Wellbeing Days” each year, encouraging you to take time to focus on yourself. We offer a variety of working style solutions for our colleagues as well.

Our continuous learning culture inspires and equips you to learn, share and grow, helping you achieve your fullest potential. As a result, at Aon, you are more connected, more relevant, and more valued.

Aon values an innovative and inclusive workplace where all colleagues feel empowered to be their authentic selves. Aon is proud to be an equal opportunity workplace.

Aon provides equal employment opportunities to all employees and applicants for employment without regard to race, colour, religion, creed, sex, sexual orientation, gender identity, national origin, age, disability, veteran, marital, domestic partner status, or other legally protected status. We welcome applications from all and provide individuals with disabilities with reasonable adjustments to participate in the job application, interview process and to perform essential job functions once onboard.