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Hi, I'm Olaf Gallagher, a Senior .NET Engineer with 25+ years of experience building high-availability payment and booking platforms at scale. I specialize in C#, ASP.NET Core, microservices (CQRS), Docker/Kubernetes, and Azure. I have led monolith-to-microservices migrations and payment orchestration with Braintree, Worldpay, and FreedomPay, establishing CI/CD and TDD to improve release frequency and reliability. I am known for large-scale refactoring (75%+ codebase reduction) and delivering resilient, event-driven APIs. My full stack experience includes a React/TypeScript customer portal, integration of multiple communications systems, and a focus on solid OO design and SOLID principles. I'm comfortable across the full development lifecycle and with data access, multi-tier architectures, and cloud-native deployments.…Hi, I'm Olaf Gallagher, a Senior .NET Engineer with 25+ years of experience building high-availability payment and booking platforms at scale. I specialize in C#, ASP.NET Core, microservices (CQRS), Docker/Kubernetes, and Azure. I have led monolith-to-microservices migrations and payment orchestration with Braintree, Worldpay, and FreedomPay, establishing CI/CD and TDD to improve release frequency and reliability. I am known for large-scale refactoring (75%+ codebase reduction) and delivering resilient, event-driven APIs. My full stack experience includes a React/TypeScript customer portal, integration of multiple communications systems, and a focus on solid OO design and SOLID principles. I'm comfortable across the full development lifecycle and with data access, multi-tier architectures, and cloud-native deployments.

Olaf G.

Full Stack Developer, Web Developer, Back-End Developer, +2

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Hi, I'm Olaf Gallagher, a Senior .NET Engineer with 25+ years of experience building high-availability payment and booking platforms at scale. I specialize in C#, ASP.NET Core, microservices (CQRS), Docker/Kubernetes, and Azure. I have led monolith-to-microservices migrations and payment orchestration with Braintree, Worldpay, and FreedomPay, establishing CI/CD and TDD to improve release frequency and reliability. I am known for large-scale refactoring (75%+ codebase reduction) and delivering resilient, event-driven APIs. My full stack experience includes a React/TypeScript customer portal, integration of multiple communications systems, and a focus on solid OO design and SOLID principles. I'm comfortable across the full development lifecycle and with data access, multi-tier architectures, and cloud-native deployments.…Hi, I'm Olaf Gallagher, a Senior .NET Engineer with 25+ years of experience building high-availability payment and booking platforms at scale. I specialize in C#, ASP.NET Core, microservices (CQRS), Docker/Kubernetes, and Azure. I have led monolith-to-microservices migrations and payment orchestration with Braintree, Worldpay, and FreedomPay, establishing CI/CD and TDD to improve release frequency and reliability. I am known for large-scale refactoring (75%+ codebase reduction) and delivering resilient, event-driven APIs. My full stack experience includes a React/TypeScript customer portal, integration of multiple communications systems, and a focus on solid OO design and SOLID principles. I'm comfortable across the full development lifecycle and with data access, multi-tier architectures, and cloud-native deployments.

Available to hire

Hi, I’m Olaf Gallagher, a Senior .NET Engineer with 25+ years of experience building high-availability payment and booking platforms at scale. I specialize in C#, ASP.NET Core, microservices (CQRS), Docker/Kubernetes, and Azure. I have led monolith-to-microservices migrations and payment orchestration with Braintree, Worldpay, and FreedomPay, establishing CI/CD and TDD to improve release frequency and reliability.

I am known for large-scale refactoring (75%+ codebase reduction) and delivering resilient, event-driven APIs. My full stack experience includes a React/TypeScript customer portal, integration of multiple communications systems, and a focus on solid OO design and SOLID principles. I’m comfortable across the full development lifecycle and with data access, multi-tier architectures, and cloud-native deployments.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Senior Software Developer at Zonal Retail Data Systems

August 31, 2025 - October 20, 2025

Led the design, development, and maintenance of a unified Booking Management and Payment Provider system. Drove monolith-to-microservices migrations and implemented a payment orchestration layer integrating Braintree, Worldpay, and FreedomPay. Built a distributed CQRS-based API using MediatR, .NET 8, Docker Containers, and RabbitMQ; created a responsive HTML5/SCSS/JavaScript frontend and a React/TypeScript customer portal. Implemented CI/CD with Azure DevOps, comprehensive TDD, and ensured reliability across multi-repo microservices in Azure.

Senior Software Developer at M &Co Trading Ltd

September 30, 2022 - October 20, 2025

Design, develop and maintain distributed microservices-based systems; implemented CQRS with MediatR, Docker/Kubernetes, and event-driven messaging with RabbitMQ. Maintained backend APIs using C#, .NET Core/5+, integrated payment providers, built a React/TypeScript customer portal and CI/CD pipelines.

Senior Software Developer at 402 Ltd

October 31, 2019 - October 20, 2025

Architected and refactored multiple client systems into microservices; integrated payment providers and built scalable backend services with SQL Server and NoSQL stores. Implemented automated tests and CI/CD pipelines; contributed to front-end development with Angular/HTML5/JS.

Senior Software Developer at Twenty Six Digital

March 31, 2017 - October 20, 2025

Developed SaaS Payroll integration and e-commerce solutions; created multi-tier architectures with .NET backend services and HTML5/JS front ends; implemented TD/Tests; contributed to data migrations and API design. Led prototyping and iterative refactoring.

Senior Software Developer at GDF Suez

December 31, 2015 - October 20, 2025

Created server-side components for enterprise energy management systems; implemented data processing services with .NET and SQL Server, and contributed to API design and messaging.

Systems Developer / Analyst at Morgan Sindall / Morgan EST

December 31, 2011 - October 20, 2025

Developed software across multiple client projects; implemented OO design patterns, data access layers, and SOA/multi-tier architectures; contributed to front-end and back-end integration across multiple platforms.

Senior Software Developer at RDT Ltd

June 30, 2012 - October 20, 2025

Systems development and analysis across work scheduling utilities, .NET web and Windows services, and data integration with various databases; focused on OO design, testing strategies, and code quality.