Open to opportunities

George Kollias

@georgekollias

Message

Senior full-stack software engineer specializing in scalable payments and fintech systems.

Netherlands

Message

What I'm looking for

I seek senior engineering roles in fintech or payments where I can lead scalable system design, improve reliability, mentor engineers, and drive automation.

I am a senior full-stack software engineer with extensive fintech experience, focused on payments, automation, and scalable web architectures. I design and deliver production-grade systems that improve reliability and developer productivity.

At Booking.com I led micro-frontend migrations, implemented SCA for post-booking payments, and built end-to-end damage policy payout automation that scaled globally. I also created monitoring, reconciliation dashboards, and release accuracy checks to ensure payment correctness across distributed systems.

I mentor engineers, run structured onboarding and bootcamps, and contribute to diversity-focused internship programs. Earlier roles include delivering enterprise workflows, RPA processes, SharePoint and fleet-management solutions, and banking operations systems.

Technically I work across React, Vue, JavaScript, Perl, Java, C#, SQL Server, MySQL, Kubernetes and Docker, and I prioritize measurable outcomes, automation, and clear operational observability.

Experience

Work history, roles, and key accomplishments

Current

Senior Full Stack Engineer

Current

Booking.com

Mar 2023 - Present (2 years 10 months)

Led architecture and implementation of micro-frontend migration and end-to-end payment solutions for the Fintech business unit, scaling damage policy payout automation from 6 countries to global adoption and improving payment reconciliation accuracy with monitoring and alerts.

JavaScript Java Perl MySQL Kubernetes Docker GraphQL

Full Stack Software Engineer

Booking.com

May 2019 - Feb 2023 (3 years 9 months)

Designed and developed guest and partner payments features including SCA for post-booking payments, bank details confirmation workflows, and Stripe release accuracy monitoring, while mentoring engineers and running onboarding programs.

Vue.Js JavaScript Perl Java MySQL Hadoop Git Payment Systems

Software Engineer

OTE

Jan 2016 - May 2019 (3 years 4 months)

Developed corporate portfolio and workflow applications centralizing project management and delivered 11 RPA processes to production, supporting over 5,000 workflow requests and building the company bot workforce.

ASP.NET MVC C++SQL Server JavaScript SharePoint RPA Softomotive

Software Engineer

VCI

Jan 2014 - Dec 2015 (1 year 11 months)

Implemented SharePoint solutions and workflows for internal OTE employee use, delivering automation and internal tools using ASP.NET MVC and SQL Server as an external associate.

ASP.NET MVC C++SharePoint SQL Server JavaScript

Software Engineer

PEC Enterprises

Jul 2013 - Dec 2013 (5 months)

Developed front-end and back-end components of a fleet management system, responsible for UX design and implementation using ASP.NET, MVVM, and SQL Server.

ASP.NET MVVM C++Silverlight SQL Server UX Design

Programmer / Senior Programmer

Accenture

Sep 2010 - Jun 2013 (2 years 9 months)

Implemented services, batches, desktop apps and stored procedures for banking and workforce management projects, supporting operations and reporting for thousands of users.

C++COBOL SQL SQL Server Stored Procedures Batch Processing

Education

Degrees, certifications, and relevant coursework

University of Crete

Bachelor of Science, Computer Science

2002 - 2008

Grade: 7.03

Activities and societies: Instructor for high school computer science (2010–2011) listed under additional experience; hands-on coursework projects using C, C++, Java, SQL, Verilog, and Assembly.

Completed a Bachelor of Science in Computer Science with coursework in AI, operating systems, algorithms, compilers, databases, and game programming.