Open to opportunities

Stephen Thomas

@stephenthomas2

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Senior full-stack engineer delivering scalable web apps, APIs, and AI-driven workflows across fintech and eCommerce.

Ireland

Message

What I'm looking for

I’m looking to build reliable, high-impact products in distributed teams—owning system design, performance, scalable APIs, and AI-driven automation (LLMs/RAG), while partnering with stakeholders and mentoring others.

As a Senior Full Stack Engineer with 10+ years of experience, I build scalable web applications, APIs, and cloud-native systems across fintech and eCommerce. I specialize in AI-driven solutions—especially LLMs and RAG—to improve automation and data-driven workflows, with a strong focus on performance and system design in distributed teams.

At Finastra, I developed Node.js and GraphQL microservices, shipped mobile features in React Native, and improved peak-time payment performance by 40% through caching redesign and routing optimizations. I also automated onboarding and compliance workflows using OpenAI for document processing and entity extraction (reducing manual review by 30%), implemented RAG pipelines for payment compliance and fraud checks, and delivered AWS-native solutions that met PCI compliance—while mentoring junior engineers and partnering closely with stakeholders to build fintech SaaS features.

Experience

Work history, roles, and key accomplishments

Current

Senior Full-Stack Engineer

Current

Finastra

Jul 2022 - Present (3 years 9 months)

Built Node.js and GraphQL microservices supporting payments, loans, and real-time transaction data. Improved peak-time payment performance by 40% via caching and routing optimizations, and reduced manual onboarding/compliance review by 30% using OpenAI-driven document processing and entity extraction.

Node Express GraphQL Redis React TypeScript AWS Lambda DynamoDB OpenAI RAG

Senior Full-Stack Engineer

Dept

May 2019 - Jun 2022 (3 years 1 month)

Developed a multitenant e-commerce platform using React, Next.js, and TailwindCSS to improve performance and customization speed. Implemented GraphQL/REST APIs with Django, enforced tenant isolation with PostgreSQL row-level security, and reduced deployment time by 50% with CI/CD; also added Redis rate limiting to stabilize peak-load performance.

React Next.js TailwindCSS GraphQL Python Django PostgreSQL Stripe Redis CI CD

Full Stack Engineer

Valtech

Aug 2016 - Apr 2019 (2 years 8 months)

Built analytics dashboards with Vue.js, D3, and Highcharts for internal and client reporting. Created Flask APIs for real-time and historical data, designed Kafka/Kinesis pipelines to reduce dashboard latency, and implemented enterprise SAML SSO for security requirements.

Vue.Js D3 HighCharts Flask Kafka Kinesis AWS EC2 S3 RDS SAML

Full Stack Engineer

Wiredmark

Jan 2015 - Jul 2016 (1 year 6 months)

Developed digital marketing and automation tools using Laravel and MySQL. Created reusable Bootstrap UI components that reduced campaign setup time by 40%, added Google Analytics/UTM tracking, and set up CI/CD with CircleCI and Heroku.