Open to opportunities

Mark Santos

@marksantos3

Message

I’m a Lead Full Stack Engineer who builds scalable JavaScript systems end to end for fintech and SaaS.

Hungary

Message

What I'm looking for

I’m looking for a team where I can own full-stack JavaScript delivery—SSR + APIs + real-time features—while driving measurable performance gains, clean CI/CD, and scalable systems in fintech or enterprise SaaS.

I’m a Fullstack JavaScript developer with 11 years of experience building scalable web applications across fintech, e-commerce, and enterprise SaaS. I deliver production systems with strong command of TypeScript, GraphQL, and real-time architectures—bringing full-stack ownership from backend API design to SSR-rendered frontend delivery.

As a Lead Full Stack Engineer at Xurge Digital Lab LLC, I architected NestJS microservices for 50,000+ daily active messaging sessions with sub-100ms delivery latency. I built a Next.js SSR dashboard that cut initial page load time by 52%, and I consolidated 14 legacy REST endpoints into a GraphQL API, reducing client data-fetching calls by 60%.

I also drive performance and reliability through caching, query optimization, and automation. At Webtown, I reduced API response times by 40% using PostgreSQL query plan optimization and Redis caching, and I established CI/CD with automated Jest and Cypress tests—reducing deployment cycles from 3 days to 4 hours.

Experience

Work history, roles, and key accomplishments

Lead Full Stack Engineer

Xurge Digital Lab Llc

Jan 2025 - Mar 2026 (1 year 2 months)

Led frontend and backend development for a TextRP enterprise messaging platform on the XRP Ledger, delivering a NestJS microservices backend handling 50,000+ daily sessions with sub-100ms delivery latency. Built Next.js SSR dashboards, introduced GraphQL over 14 legacy REST endpoints, and implemented Socket.io real-time notifications, while improving deployment speed from 3 days to 4 hours via CI/

NestJS Next.js TypeScript GraphQL Socket.IO PostgreSQL Redis Docker GitHub Actions

Senior Full Stack JavaScript Developer

Webtown

Jul 2020 - Jan 2025 (4 years 6 months)

Built and led enterprise web applications across e-commerce and fintech, including a Vue 3/Node.js checkout platform processing 120,000+ monthly transactions with 99.95% uptime. Optimized PostgreSQL with Redis caching to reduce API response times by 40%, migrated a jQuery monolith to Angular 14 (bundle size -38%, Lighthouse 54 to 91), and mentored 3 junior developers.

Vue.Js 3 Node.Js Development NestJS TypeScript PostgreSQL Redis Gitlab CI Performance Optimization

Full Stack JavaScript Developer

Miro Ai

May 2018 - May 2020 (2 years)

Developed React dashboards and real-time data APIs for sports analytics workflows serving 8 league clients. Implemented Node.js/Express REST ingestion for 2,000+ events per minute with zero data loss, added WebSocket live overlays under 500ms refresh, and used GraphQL subscriptions to cut polling by 70%.

React TypeScript GraphQL GraphQL Subscriptions WebSockets MongoDB Redux AWS S3

Junior Frontend Developer

GenieX

Jan 2015 - Apr 2018 (3 years 3 months)

Built jQuery and early Angular interfaces for POS and ERP modules used across 12 retail distribution clients in Southeast Asia. Supported migration of PHP-rendered views to a single-page Angular app, reducing page transition times by 45%, and improved frontend quality with unit tests (78% coverage).