Mark Dylan Cosca

Mark Dylan Cosca

Senior Full Stack DeveloperReact, Node.js, AI Agents & Headless Commerce

I build fast, reliable web products end to end, from high-traffic Shopify Plus and headless storefronts to full-stack apps and production AI agents.

Open to remote work · Overlaps with US Pacific, CET and AEST hours

About

Who I am

I'm a senior full stack developer with 9+ years of experience, specializing in TypeScript, React and Next.js products backed by Node.js and Python services, PostgreSQL and vector data, and production AI agents built with tool calling, retrieval and evaluations. I've spent 7+ years deep in Shopify, from Liquid themes and custom apps to Hydrogen since its early releases, and I've led high-traffic work such as Spanx, serving 10M monthly visitors at 99% uptime. I enjoy owning products end to end, from client scoping and codebase architecture to the team standards that keep delivery smooth, and I'm genuinely excited about bringing AI into real products in ways people can trust.

Selected work

Client case studies

Side projects

Products I've built and own end to end.

Other brands I've built for

What I do

How I can help

Skills

Tools I use, and how

Recent Shopify Plus migrations

  • checkout.liquid → Checkout Extensibility
  • Scripts → Functions
  • Pixels → server-side tracking
  • Liquid → headless Hydrogen

Full Stack

  • TypeScript
  • JavaScript (ES6+)
  • React
  • Next.js (App Router)
  • Remix
  • Node.js
  • Express
  • Fastify
  • NestJS
  • Python

AI Engineering

  • OpenAI SDK
  • Claude SDK
  • Vercel AI SDK
  • Tool-calling agents
  • RAG
  • Vector databases
  • Structured outputs
  • Evaluations
  • Human approval steps
  • MCP

Data & Architecture

  • PostgreSQL
  • Supabase
  • MongoDB
  • MySQL
  • Redis
  • Multi-tenant & role-based access
  • Microservices
  • Queues & background jobs
  • WebSockets

Commerce

  • Shopify Plus
  • Hydrogen & Oxygen
  • Liquid
  • Online Store 2.0
  • Checkout Extensibility
  • Functions
  • Custom apps
  • App Bridge & Polaris
  • 3PL & multi-warehouse
  • i18n & multi-currency
More skills (5 groups)

Integrations & Growth

  • REST
  • GraphQL
  • Webhooks
  • OAuth / JWT
  • Stripe
  • Klaviyo
  • HubSpot
  • GoHighLevel
  • Twilio
  • Meta Conversions API
  • Server-side tracking
  • GA4
  • GTM
  • A/B testing (Intelligems, Convert)

Performance & Quality

  • Core Web Vitals
  • Lighthouse
  • Accessibility (WCAG, 508)
  • Jest
  • Vitest
  • Playwright
  • React Testing Library
  • TDD

Mobile

  • Kotlin (Android)
  • SwiftUI (iOS)
  • Ionic
  • Quasar

DevOps & Cloud

  • Docker
  • GitHub Actions
  • CI/CD
  • AWS / GCP
  • Vercel
  • Netlify
  • Cloudflare Workers & D1
  • Sentry
  • Logging, monitoring & backups

Leadership & AI Tools

  • Codebase architecture
  • Scoping & estimates
  • Team standards
  • Code review
  • Mentoring
  • Claude Code
  • Cursor
  • GitHub Copilot

Experience

The road so far

  1. Form Factory | Software Engineer (Full-time)

    Sep 2022 – Sep 2026

    Agency delivering Shopify Plus, headless and custom web builds for global brands such as Spanx, Turtle Beach, Solo Brands and Corza.

    • Led architecture and delivery of high-traffic storefronts and web applications for global brands, scoping work directly with clients and owning it through to production.
    • Delivered key Shopify Plus upgrades end to end, including checkout.liquid to Checkout Extensibility, Scripts to Functions, browser pixels to server-side tracking, and Liquid themes to headless Hydrogen builds.
    • Built full-stack products and AI agents with Node.js, Python, PostgreSQL and vector search, using tool calling, retrieval, structured outputs and evaluations, with human approval before agents act.
    • Drove CRO development and A/B tests that lifted conversion and average order value, and shortened build and deploy times through CI/CD improvements.
    • Set coding standards and codebase architecture for the team, reviewed code, mentored developers, and delivered several projects solo from first commit to launch.
  2. MindArc | Frontend Developer (Full-time)

    Oct 2021 – May 2022

    • Customized existing Shopify themes and built custom Liquid themes, plus fast React and Vue storefronts for global brands.
    • Built custom Shopify apps and connected stores to Node.js services and third-party REST APIs.
  3. Digital Studio / LiveCrossing | Software Engineer (Full-time)

    Mar 2019 – Oct 2021

    • Led development of a storefront on a custom e-commerce platform, built with PHP/Laravel and Vue.js.
    • Took features from architecture through to release, working on both the frontend and backend.
  4. Skubbs Inc | Web/Mobile Developer (Full-time)

    Jul 2018 – Mar 2019

    • Developed responsive websites and hybrid mobile apps using WordPress, Vue.js, Ionic and Quasar.
  5. Fullmoon Outdoor | Developer (Full-time)

    Jul 2017 – Jul 2018

    • Developed websites and custom WordPress themes with HTML, CSS, JavaScript and PHP, and handled on-site SEO.
  6. Informatics College Northgate | Bachelor of Science in Information Technology

    Jun 2014 – May 2017

  7. Certifications | Verify on Credly ↗︎

    • Shopify Apps Development
    • Liquid Storefront
    • Headless at Shopify for Developers

How I work

Ownership, end to end

Contact

Let's work together

Looking for a senior full stack developer? I build fast, reliable web products end to end, from high-traffic Shopify Plus and headless storefronts to full-stack apps and production AI agents. I'm open to remote work, and the best way to reach me is by email.

coscamarkdylan@hotmail.com

Portrait of Mark Dylan Cosca