Istvan – AWS, React, Ruby

An e-commerce platform serving thousands of merchants and millions of customers across the UK. The product supports online shopping and merchant operations at scale, with a strong focus on reliability, observability, and infrastructure performance.

• Improved platform reliability, observability, and infrastructure excellence;
• Moved the product catalogue to a more event-driven approach using AWS EventBridge, SQS, Lambda, and DynamoDB;
• Designed and implemented a new service to improve delivery prediction;
• Decommissioned legacy systems.

A wealth management app that keeps an inventory of a user’s assets. The product helps organize financial holdings in one place and supports decision-making as the portfolio grows.

• Defined and executed the technical vision and product roadmap;
• Oversaw technology architecture decisions and infrastructure;
• Led AI/ML feature development and integration strategy;
• Ensured scalability and performance as the business grew;
• Managed technical debt through quarterly assessment and reduction plans.

A platform for application assembly and reusable building blocks, serving hundreds of SME customers. It supported multiple backend stacks and streamlined component maintenance, workspace development, and CI/CD automation at scale.

• Led technical transformation across engineering teams;
• Designed a stack-agnostic platform architecture supporting multiple backend stacks;
• Built the Blocksmith GenAI framework for automated component maintenance;
• Designed and implemented Blocks Workspace IDE for turn-key local development;
• Architected modular CI/CD pipelines for 500+ components;
• Built a Neo4j-based dependency graph to improve stack upgrade efficiency.

An e-commerce platform serving thousands of merchants and millions of customers across the UK. The product supports online shopping and merchant operations at scale, with a strong focus on reliability, observability, and infrastructure performance.

• Transitioned from Principal Engineer after the Head of Architecture left, as the organization needed a more structured architecture function;
• Defined the future-state architecture and solution design for replatforming from a legacy system;
• Provided implementation governance for the replatforming initiative;
• Designed the architecture, solution design, and prototype for a new Apple Pay payment method;
• Shaped the architecture for a new stock management system;
• Provided implementation governance for the payment method rollout and worked across engineering teams to design solutions and architecture overviews;
• Led re-platforming by extracting Basket and Checkout experiences from a monolith into domain-aligned components;
• Led design and implementation for APIs and microservices;
• Fixed a compound precision and rounding problem in the tax system;
• Completed gift card capability integration using GiveX.

An invoicing application for small businesses, and one of the first successful web apps built with Ruby on Rails. The product helped small businesses manage invoicing and payments in a simple, web-based workflow.

• Hired and trained an offshore development team;
• Designed architecture for new features and the implementation plan;
• Implemented the Estimates feature;
• Implemented a secure credit card payment solution.