Bart Zalas · Poland (CET) · Remote

I help Shopify Plus and Magento brands improve site speed, fix revenue-impacting issues, and increase conversions.

15+ years in eCommerce · Shopify Plus · Magento 2 Certified · Core Web Vitals · DevOps · AI-assisted delivery

Book a Free 30-Minute Consultation

BZ

Case Studies

Shopify Plus, Magento, and custom app work—problem, solution, and outcome.

Shopify Custom Apps & Functions

cbdMD, pawCBD, Bluebird Botanicals, Herbal Oasis, AtrxLabs

Problem

Brands needed Rebuy-like upsells, tier pricing, VIP shipping, free gifts, and cart-drawer promos without stacking multiple SaaS subscriptions.

Solution

Built and rolled out custom Shopify apps and Functions—VIP shipping, free-gift popup, tier pricing, limited-time cart-drawer offers, Rebuy-style widgets shared across stores, plus a custom subscription app for a non-Plus diapers startup.

Results

  • VIP Shipping, free-gift popup, tier pricing, and cart-drawer LTO apps live on Plus storefronts
  • Shopify Functions powering checkout and cart discount logic
  • Rebuy-style widget patterns reused across multiple brands
  • Custom subscription app delivered for a non-Plus startup (confidential)
Shopify Functions
Checkout UI
Theme app extensions
Cart drawer
GraphQL
Node.js

Problem

Legacy Magento storefronts were slow, hard to maintain, and blocking growth on a regulated US market.

Solution

Led Magento-to-Shopify Plus migration, custom theme work, checkout extensibility, and compliance-focused storefront logic.

Results

  • Improved Core Web Vitals (INP, LCP) across key templates
  • Reduced page load time on product and collection pages
  • Built Delta-9 state restriction logic for compliant sales
  • Recharge subscription integrations
  • Klaviyo marketing integrations
Shopify Plus
Shopify Functions
Checkout UI
Recharge
Klaviyo

Magento Hyvä — B2B Foodservice

7daychef (Swanwick Foodservice)

Problem

Slow Magento store, outdated stack, and infrastructure that couldn't support catalog scale or reliable checkout.

Solution

Magento 1→2 migration, Hyvä theme rebuild, caching layer, and full DevOps setup.

Results

  • Redis and Varnish caching for faster TTFB
  • Cloudflare in front of production traffic
  • ElasticSearch for catalog performance
  • CI/CD and staging/production environments
Magento 2
Hyvä
Redis
Varnish
Cloudflare
DigitalOcean

Problem

Checkout failures and Stripe integration issues were blocking orders and damaging conversion.

Solution

Debugged payment flow, Stripe integration, and checkout edge cases end to end.

Results

  • Resolved checkout failures blocking completed orders
  • Fixed Stripe integration and payment edge cases
  • Stabilized checkout for ongoing subscription revenue
Shopify
Stripe
Checkout
JavaScript

Problem

AI-generated storefront sections weren't merchant-safe—content and layout couldn't be edited in the Shopify theme customizer.

Solution

Converted the AI project into proper Shopify Liquid sections and blocks, wired for Theme Customizer editing (ready-to-wear, made-to-measure, cloth story, and related homepage modules).

Results

  • New homepage and collection sections editable in Shopify Customizer
  • Merchants can update copy, media, and CTAs without developer handoff
  • Production Shopify storefront live for luxury menswear (Markham / Toronto)
Shopify
Liquid
Theme sections
Theme Customizer
AI → production

Problem

Lovable prototype needed a clean transfer into a maintainable production site for a GTA vinyl resurfacing brand.

Solution

Took the Lovable build, transferred ownership/code, hardened for production hosting, and shipped the marketing site (services, portfolio, about).

Results

  • Live production site for commercial & residential resurfacing
  • Lovable prototype moved off prototype hosting into client-owned delivery
  • Clear services and portfolio structure for Greater Toronto Area leads
Lovable
React
Production handoff
Hosting

Problem

Clinic needed the Lovable-built marketing site transferred into a stable production environment with booking and service pages intact.

Solution

Transferred the Lovable project to production, connected content and booking flows, and delivered the live psychology centre site.

Results

  • Production site live for Mississauga / GTA psychology services
  • Services, assessments, and specialty programs structured for patients and referrers
  • Jane App booking path retained for appointments
Lovable
React
Production handoff
Azure

Available for White-Label Agency Partnerships

US agencies often need a reliable senior developer for overflow work, migrations, and performance fixes—without hiring full-time.

  • US time zone overlap
  • Long-term contracts
  • Shopify Plus & Magento 2
  • White-label friendly
  • AI-assisted delivery for faster turnaround
Partner With Me

Services

Shopify Plus Developer, Magento 2 Developer, and DevOps for ecommerce teams.

Shopify Plus

  • ·Theme development
  • ·Custom Shopify apps
  • ·Shopify Functions
  • ·Checkout Extensibility
  • ·Rebuy-style upsell widgets
  • ·Recharge subscriptions
  • ·Klaviyo integrations
  • ·Shopify migration expert (Magento to Shopify)

Magento 2

  • ·Magento Hyvä developer
  • ·Performance optimization
  • ·Custom modules
  • ·Third-party integrations
  • ·Magento 1 to Magento 2 migrations

DevOps

  • ·AWS
  • ·DigitalOcean
  • ·Cloudflare
  • ·CI/CD pipelines
  • ·Staging & production environments

AI-Assisted Development

  • ·Cursor IDE & AI agents for faster implementation
  • ·Code review and refactoring with AI support
  • ·Debugging across local, staging, and production (SSH)
  • ·Documentation and technical problem-solving

Shopify Apps

Custom apps, Functions, and cart-drawer extensions for promotions, shipping, gifts, and subscriptions—deployed across Plus storefronts and one non-Plus startup.

VIP Shipping

Priority / expedited shipping upsell integrated into cart and checkout flows.

Free Gift Popup

On-site popup and cart rules that auto-add eligible free gifts.

Tier Pricing

Quantity-based tier pricing for multi-unit and wholesale-style buys.

Limited Time Offer — Cart Drawer

Time-boxed promotions surfaced in the cart drawer to lift AOV before checkout.

Shopify Functions Apps

Checkout and cart logic via Shopify Functions—discounts, validation, and custom pricing rules.

Custom Subscriptions

Confidential

Full subscription flow for a non-Plus startup (diapers store)—no Shopify Plus required.

Rebuy-Style Widgets

Cross-sell, upsell, and frequently-bought-together widgets replicated across multiple stores.

Implemented for

Custom subscription app also built for a non-Plus diapers startup (confidential—no public link).

What Clients Say

Bart fixed issues that other developers couldn't—fast, clear communication, and solid Shopify Plus work.

Agency client, US ecommerce

Great Shopify Plus developer. Reliable on remote contracts and comfortable with complex checkout requirements.

Brand stakeholder, CBD vertical

Reliable Magento expert—performance, Hyvä, and DevOps. Exactly what we needed for a long-term engagement.

Technical lead, UK agency

About

Shopify Plus Developer and Magento 2 Certified expert with 15+ years in ecommerce. I help US brands and agencies fix revenue-impacting issues—Shopify performance optimization, Shopify speed optimization, checkout failures, and Magento Hyvä performance. I use AI-assisted workflows (Cursor IDE & agents) to deliver faster audits, refactors, and fixes on local and server environments. Available for white-label agency partnerships and long-term remote contracts with US time zone overlap.

Remote from Poland with overlap for US teams. Adobe Certified Magento Commerce Developer. I use AI tools (Cursor IDE & agents) to move faster on performance work, checkout fixes, and Magento Hyvä projects—without cutting corners on quality.

Education

Olsztyn University of Warmia-Mazury

20042010
Bachelor's Degree, MScEng

Skills

Magento 1 & 2
Hyva
JavaScript
AlpineJs
Tailwind
AWS
TypeScript
React/Next.js/Remix
Shopify Plus
Shopify Functions
Custom Shopify apps
Node.js
GraphQL
Cursor IDE
Cursor Agent (AI-assisted dev)
Server / SSH workflows

Book a Free 30-Minute Consultation

Tell me what's broken—slow pages, checkout issues, a migration, or agency overflow. I'll suggest a practical next step.