Hi, I'm Michael John Mercado

Senior Shopify Developer with full-stack capabilities in modern web technologies

About Me

I'm a passionate developer with 8+ of experience, specializing in Shopify Plus development and building scalable web applications. My expertise lies in high-performance e-commerce solutions, custom checkout functions, and full-stack enterprise platforms.

Michael John Mercado

What I Do

I specialize in Shopify Plus development, crafting custom themes, Checkout UI Extensions, and Shopify Functions that elevate conversion and customer retention. Combined with solid full-stack skills across React, Next.js, and Node.js, I architect scalable back-office automation, POS platforms, and accessible e-commerce experiences.

8+
Years Experience

Core Competencies

Here are the technologies and skills I work with to build scalable solutions

Shopify Plus & Liquid

Custom theme architecture & Liquid
Shopify Functions & Checkout Extensibility
Shopify CLI & Storefront/Admin GraphQL APIs
Accessibility audits & WCAG 2.1/2.2 AA

Frontend Engineering

React, Next.js (App Router), TypeScript
React Native / Expo (Mobile apps)
Tailwind CSS, shadcn/ui, Framer Motion
TanStack Query, State Management, Vitest

Backend & Architecture

Node.js, Express, Bun, BullMQ, Turborepo
PostgreSQL, Supabase, Drizzle ORM
RESTful APIs, WebSockets, Cloudflare Workers
BFF security, sealed cookies, token mutex

DevOps & Integrations

Git/GitHub, CI/CD, Docker
Klaviyo, GA4, Meta Pixels, Commission Junction
Hardware POS integrations (Barcode, Thermal Print)
Outbox pattern, queue relays, async workers

Collaboration & Agile

Remote asynchronous collaboration
Agile / Scrum sprints, code reviews
Jira, Linear, Asana, GitHub Projects
Technical documentation & architecture plans

Design & UX

Responsive & mobile-first architecture
Figma to pixel-perfect code
Core Web Vitals & speed optimization
Accessible component patterns (ARIA, keyboard UX)

Professional Experience

My journey across enterprise Shopify Plus and modern full-stack development

Senior Shopify Developer

The Walking Company LLC

2023 – Present | Fulltime
  • • Built and modified Shopify themes ensuring consistent brand identity
  • • Implemented efficient local development processes using Shopify CLI and GitHub
  • • Developed checkout extensions and Shopify Functions for enhanced backend processes
  • • Managed custom CMS integration for vendor product uploads and order processing
  • • Set up Google Analytics, GA4, and Facebook Pixel for performance tracking
  • • Accessibility Compliance Leadership: Lead developer partnering with Allyant on comprehensive WCAG 2.1/2.2 AA accessibility remediation across brand stores
  • • Storefront Rollouts: Led technical development for FootSmart Redesign V3, ABEO New Customer Accounts migration, and custom React recommendation quizzes

Full-Stack Developer

LocalSolve PH

2023 – Present | Freelance
  • • Built modern web applications using Node.js, TypeScript, Express, React, Next.js, and Vite
  • • Designed RESTful APIs and server-side applications with PostgreSQL, SQL, and MongoDB
  • • Developed responsive user interfaces ensuring seamless UX across devices
  • • Optimized application performance through code optimization and database tuning
  • • QuickNeeds Merchant Web Platform: Built retail POS web application with Next.js 16, React 19, Tailwind CSS v4, Bun, and TanStack Query
  • • POS Hardware & Ergonomics: Integrated USB barcode wedge scanner detection (<50ms keystroke bursts), dual-binding keyboard hotkeys, and 58mm/80mm thermal receipt printing
  • • Merchant Mobile App: Built cross-platform mobile app using React Native, Expo Router, and NativeWind with real-time WebSocket order tracking

Fullstack Developer

Clicktek Consulting Inc.

2021 – 2023 | Full-time
  • • Created custom Shopify Plus themes from Figma designs
  • • Built and maintained custom Shopify apps deployed on Ubuntu servers
  • • Conducted performance audits and optimized store speed
  • • Provided strategic guidance on app usage and third-party integrations
  • • Integrated customer loyalty rewards systems directly with Shopify checkout and customer portals

Jr. Frontend Developer

Xpanse Technologies Inc.

2018 – 2021 | Full-time
  • • Translated PSD designs into fully functional Shopify themes
  • • Focused on improving site performance metrics and addressing technical issues
  • • Coordinated with project managers to align development tasks with business goals
  • • Contributed to multi-store migrations from legacy platforms to Shopify for major national brands

Let's Connect

I'm always open to new opportunities and exciting technical challenges. Let's discuss how we can build something great together!