Eoin McDonnell

Led the architecture and delivery of high-traffic, cloud-native applications with a strong focus on scalability, performance, and developer efficiency. Designed and maintained AWS infrastructure using ECS/Fargate, partnering closely with DevOps and SRE teams to ensure reliable performance during peak usage. Drove modernization of CI/CD practices by standardizing GitHub Actions, Docker, and Terraform workflows, enabling fully automated, trunk-based deployments and significantly improving delivery speed and reliability. Built real-time, data-intensive dashboards using Typescript, emphasizing maintainable component architecture, performance optimization, and exceptional UX. Led multiple AI initiatives, including production RAG systems using vector databases and LLMs to power conversational and self-service experiences. Optimized embedding pipelines and retrieval strategies to reduce latency and improve response quality. Implemented OCR pipelines to automate structured data extraction from images such as IDs and receipts. Provided technical leadership across frontend, backend, and data layers, defined GraphQL API standards using FastAPI, and mentored engineers through code reviews, architectural guidance, and Agile collaboration with Product, Design, and QA. Engineered and optimized Prometheus metrics pipelines and Grafana dashboards for ECS /Fargate services, integrating Alertmanager with EventBridge and Slack to deliver real-time monitoring and automated alerting.

Provided mentorship and technical guidance through hundreds of code reviews, improving team growth and overall code quality. Modernized legacy security and access-control platforms into cloud-native architectures with caching, load balancing, and automated failover, supporting thousands of daily users. Established and maintained CI/CD pipelines with Jenkins, improving deployment speed and release cycle efficiency. Translated complex business and compliance requirements into scalable platform features, enhancing adoption and engagement. Advanced frontend engineering standards with modern frameworks and PWA capabilities, improving mobile performance and load times. Integrated third-party APIs including Google Maps, Twilio, and Stripe to enable real-time geolocation, communication, and payment workflows. Designed and implemented scalable data management systems using Google Cloud Firestore and BigQuery. Produced interactive dashboards and visualizations with Chart.js and D3.js. Delivered serverless backend services with Firebase Authentication and Cloud Firestore for scalable user handling. Applied XGBoost models to analyze user behavior and predict feature adoption, optimized Snowflake data warehouses, constructed Elasticsearch product discovery solutions visualized via Kibana, and improved MySQL database performance through query tuning and indexing.

Led backend and platform development for mission-critical security systems serving high-availability environments. Designed and implemented RESTful APIs using ASP.NET Core, emphasizing security, scalability, and performance. Played a central role in transitioning monolithic applications to a microservices architecture, enabling faster releases and improved resilience. Introduced event-driven processing with RabbitMQ and Kafka to handle high-volume device and system events in real time. Built frontend features using Vue.js and TypeScript, optimized API throughput through caching and rate limiting, and supported a polyglot architecture. Migrated on-prem systems to Azure, improving operational efficiency, reliability, and cost control while enforcing consistent authentication and role-based access control across services.

Developed internal platforms and tools supporting business operations, data workflows, and reporting. Built backend services with Node.js and SQL Server, and delivered AngularJS frontends that streamlined internal processes and reduced task completion time. Owned database administration and optimization for SQL Server environments, improving backup, recovery, and query performance. Designed ETL pipelines and dashboards using T-SQL and SSIS to improve data accuracy and decision-making across teams. Automated QA and regression testing with Python, significantly reducing manual testing effort and increasing release confidence. Also built internal documentation and knowledge-sharing platforms that improved onboarding and reduced recurring support requests.

Developed and maintained enterprise web applications using Java 6, Spring 3, Hibernate 3, JSP/Servlets, and JavaScript, improving responsiveness and usability. Built interactive dashboards with jQuery, AJAX, and Flot/jqPlot, and created SOAP-based web services (WSDL) for secure communication with external systems. Managed builds, deployments, and source control with Maven, Ant, SVN, and Tomcat, while monitoring server performance to ensure reliability and prevent regressions.

Developed and maintained Java EE portal applications with server-rendered UIs using HTML, JSP, CSS, and JavaScript. Implemented early AJAX techniques to enhance interactivity and improve user experience. Supported secure PKI-based e-signature workflows, including certificate validation and compliance-ready audit logging. Executed UI and regression testing to identify defects prior to production releases, contributing to improved application stability and reliability.