Aggelos – Typescript, AWS, Node.js

Software that helps water utilities predict pipe failures and optimize infrastructure decisions.

• Designed and maintained systems handling datasets representing millions of physical assets, with a strong focus on data modeling, storage strategy, and query performance.
• Implemented complex geospatial queries and ensured ESRI compatibility for large-scale spatial analysis.
• Built and tuned a caching layer to optimize performance for data-heavy and geospatial workloads.
• Worked across PostgreSQL and MongoDB, selecting the appropriate database per use case and applying schema design and query optimization best practices.
• Developed event-driven backend services on AWS infrastructure, using AWS Lambda to offload heavy workloads and avoid blocking the Node.js main thread.
• Managed cloud infrastructure using Infrastructure provisioning via AWS CDK, covering deployment, scalability, and environment consistency.
• Contributed to the frontend architecture using Redux Saga for complex asynchronous user flows.

An enterprise B2B e-commerce platform built specifically for supermarkets, grocery retail chains, and FMCG brands.

• Built and evolved the company's backend using Node.js and Typescript, maintaining OpenAPI-aligned APIs for core e-commerce flows, delivery logic, and merchant operations at scale.
• Led the design and development of the merchant-side application, including real-time order updates via Web Sockets and Redis-based distribution for horizontal scaling.
• Led backend changes for multi-currency and multi-timezone support across Greece, the USA, the United Kingdom, and Saudi Arabia.
• Designed and maintained complex backend workflows for user groups, targeted discount campaigns, and delivery timeslots.
• Took ownership of production stability by addressing memory leaks and performance issues using heap snapshots, continuous profiling, and real-time production metrics.
• Set up and actively monitored Datadog, New Relic, Heroku, and MongoDB Atlas, while applying MongoDB schema design, indexing, and query optimization best practices.
• Orchestrated ERP integrations such as Lightspeed, synchronizing products, stock, categories, and images in near real time under high traffic.

A leading financial technology company that specializes in software solutions for financial advisors.

• Worked on a Smart Cities project, contributing across backend, frontend, and production deployment in an enterprise environment.
• Contributed to public sector systems for two organizations, supporting applications with direct operational impact on national energy infrastructure.
• Developed and maintained FastAPI backend services supporting complex multi-role permission models and role-based access for dashboards and internal workflows.
• Built React user interfaces for the main application and an internal administrative dashboard used daily by end users and company staff.
• Contributed to the consolidation of multiple independent applications into a unified platform, laying the foundation for the platform
• Designed and delivered new features for the platform, improving performance and usability, and contributing to a 20% increase in user engagement.
• Containerized services with Docker and handled deployment, configuration, and troubleshooting on unmanaged Ubuntu servers.