Shopify Partner Agency

The Shopify engineering partner for growing ecommerce brands

We help D2C brands build, optimize and scale Shopify stores — from complex development and migrations to integrations, international expansion and CRO implementation.

Engineering-led. Commerce-aware. Built to last.

Shopify Development · Store Builds & Migrations · Apps & Extensions · CRO Implementation · Performance Optimization

Selected ecommerce brands we’ve worked with

From emerging DTC brands to established ecommerce businesses worldwide

When Shopify starts getting complicated.

Growth brings complexity. More traffic, more markets, more apps, more integrations and more custom requirements can turn a simple Shopify store into a technical bottleneck.

Conversion

Your store works, but your mobile conversion rate isn't where it should be.

Performance

Apps, pixels and scripts are slowing down your storefront without you knowing which ones are responsible.

Scalability

You've outgrown your current Shopify setup and need to know what's next — Advanced, Plus or a better architecture.

Migration

You're moving from Magento or another platform and can't afford to lose SEO, catalogue data or order history.

CRO & Growth

Your CRO team has great ideas, but you need engineers who can turn them into clean, production-ready Shopify experiences.

International

You're expanding into new markets and need Shopify Markets, currencies, localization and storefront architecture to work together.

These aren’t just Shopify problems. They’re business problems.

We solve them with technical depth built for the long term.

Talk to a Shopify Expert →
How We Work

Strategy is only as good as its implementation.

Great ideas — whether they come from your team, your design agency, or your analytics — only move the needle when they’re built correctly into the platform.

We take those ideas and ship them as clean, fast, maintainable Shopify code. No app bloat, no shortcuts, no technical debt that causes problems six months later.

Pixel-Perfect Builds

Translating high-fidelity designs, tests, and requirements into clean Liquid — without app clutter or workarounds.

Mobile-First Focus

Every change we ship is optimized for small screens — where the majority of your traffic and revenue decisions happen.

No Code Bloat

We build directly into the theme where it makes sense — keeping your store fast, lean and easy to maintain over time.

CRO Implementation

A/B tests, pricing experiments, checkout changes and conversion-focused UI — built to spec and integrated cleanly with platforms like VWO and Intelligems.

What We Do

End-to-end Shopify development.

From store builds and platform migrations to custom development, integrations and ongoing technical support.

01

Shopify Store Development

From high-growth brands on Basic to enterprise merchants on Plus — we build clean, fast, maintainable Shopify storefronts that scale with your business.

  • Custom themes & OS 2.0
  • Custom sections & blocks
  • Collection & search UX
  • Cart & checkout flows
02

Plan Migrations & Upgrades

Moving from Basic → Advanced → Plus, or from Magento/WooCommerce to Shopify? We handle the technical complexity of the transition end to end.

  • Basic → Advanced → Plus
  • Magento → Shopify migrations
  • SEO & URL preservation
  • App stack rationalisation
03

Performance Diagnostics

White-hat, root-cause approach. We identify exactly what is slowing your store — whether it's a third-party app, an unoptimised image pipeline, or a tracking pixel firing twice.

  • App & script impact audit
  • Core Web Vitals (LCP/CLS/INP)
  • Mobile speed focus
  • Real-user experience metrics
04

Shopify Markets & International

Launch across multiple countries with localised storefronts, multi-currency pricing, translated content, and Shopify Markets configuration.

  • Shopify Markets setup
  • Multi-currency & pricing
  • Localised content & SEO
  • International checkout flows
05

Custom Shopify Development

When standard Shopify capabilities aren't enough. We build custom app blocks, Shopify Functions, and API-driven experiences tailored to your business logic.

  • Product configurators & builders
  • Custom bundle & promotion logic
  • Shopify Functions & Flow
  • Admin & Storefront API
06

System Integrations

Connect Shopify to your ERP, CRM, inventory system, subscription engine, or any custom internal tool your business depends on.

  • GraphQL & REST APIs
  • Webhooks & Shopify Flow
  • ERP / CRM / WMS sync
  • Custom middleware layers
07

Headless & Mobile Commerce

For brands that need more control over their frontend — headless Shopify with a custom React/Next.js storefront, or native mobile commerce experiences.

  • Headless Shopify (Next.js)
  • Storefront API integration
  • Mobile app development
  • Hybrid PWA experiences
08

Ongoing Engineering Partner

We act as an extension of your team — shipping features, troubleshooting third-party apps, supporting campaigns, and evolving the store as your business grows.

  • Retainer-based support
  • App conflict troubleshooting
  • Campaign & landing pages
  • Technical consulting

Proven Outcomes

Selected Shopify Projects

We focus on building robust, high-converting platforms instead of simple templates.

Shopify Basic → Plus · 3+ Year Partnership
Perk Clothing

Perk Clothing

Perk started on Shopify Basic and today operates on Shopify Plus. For over three years, CartScaler has been their dedicated remote engineering team — shipping new features, managing platform upgrades, building bundle and promotion mechanics, and continuously improving mobile performance as the brand has grown.

Long-Term PartnershipBasic → Plus JourneyMobile UXOngoing EngineeringA/B Testing
Custom Product Configurator · B2B + Retail
Apolis Global

Apolis Global

Built a custom bag-personalization experience that connects seamlessly with Shopify’s cart and checkout. Powered by AWS Lambda, it is designed to scale reliably during traffic peaks. The same storefront supports wholesale and direct-to-consumer sales, with pricing, availability and purchasing experiences adapting to each buyer type.

Product CustomizerAWS LambdaB2B + RetailNative Shopify Checkout
Shopify Plus Development & Multi-Region
Ecoy

Ecoy

Engineered scalable Shopify Plus storefront architecture with custom sections, streamlined subscription experience, and optimized mobile checkout for Australia's leading eco-bedding brand.

Shopify PlusCustom ThemesSubscription UXMobile Speed
International Expansion · 6+ Country Launch
Bella Vita Luxe

Bella Vita Luxe

With a strong existing presence in India, Bella Vita Luxe approached CartScaler to plan and execute their international scaling strategy. We built and launched storefronts across 6+ countries — including localised pricing, currency, content, and checkout flows — using Shopify Markets to manage the complexity without fragmenting the tech stack.

Shopify MarketsInternational Launch6+ CountriesLocalised Checkout

Ecosystem Expertise

Shopify Apps We Work With

We integrate and customize leading ecommerce platforms across marketing, reviews, subscriptions, experimentation, returns and fulfilment.

Marketing, CRM & SMS

Configuring complex email flows, subscriber syncs, and custom customer tracking schemas.

KlaviyoKlaviyoAttentiveAttentivePostscriptPostscriptSendlaneSendlane

Reviews, UGC & Loyalty

Integrating social proof, user-generated content sliders, and rewards interfaces smoothly.

OkendoOkendoJudge.meJudge.meYotpoYotpoLooxLoox

Subscriptions & Cart

Developing seamless subscription portals and custom customer retention tools.

SkioSkioRechargeRechargeLoop SubscriptionsLoop SubscriptionsSmartrrSmartrr

Experimentation & Optimization

Implementing A/B tests, pricing experiments, theme tests, and approved CRO variations.

IntelligemsIntelligemsVWOVWOElevateElevate

Client Feedback

Trusted by brands at every stage.

From growing Shopify stores to Shopify Plus—see what our clients say.

We started on Shopify Advanced and CartScaler helped us plan and execute our transition to Plus without disrupting a single day of sales. They handled migrations, app audit, and checkout extensibility — while keeping the site fast throughout.

Head of Ecommerce

8-Figure DTC Apparel Brand

Shopify Plus MigrationCheckout Extensibility

CartScaler ran a deep performance audit on our store. They isolated a single third-party reviews widget that was delaying our LCP by 1.8 seconds on mobile. Removing and replacing it properly added significant improvement to our conversion rate.

Director of Technology

Global Health & Nutrition Brand

Performance AuditMobile Speed

They're our technical implementation partner for all CRO work. Our strategy team designs the tests and hypotheses, CartScaler builds them cleanly into the Shopify theme without introducing app dependencies or slowing the site down.

VP of Growth & Optimization

International Cosmetics Retailer

CRO EngineeringShopify Theme

Launching across four countries with Shopify Markets felt complex until CartScaler took it on. They configured localised pricing, translated content architecture, and region-specific checkout flows — all in one clean deployment.

CTO

Multi-Market D2C Brand

Shopify MarketsMulti-Country Launch

For Business Leaders

You don't need another development vendor. You need a technical partner that translates storefront performance and design directly into commercial outcomes.

  • Conversion Rate

    Removing visual clutter, checkout friction, and sizing doubts.

  • Storefront Speed

    Maximizing SEO ranking and paid advertising return on investment.

  • Merchandising Power

    Allowing your marketing team to launch dynamic promotions & landing pages.

  • Global Scaling

    Unlocking international checkout support, multi-currency, and localized B2B setups.

For Tech & Product Teams

We speak your language. We write clean code, handle complex APIs, work with version control, and follow native Shopify architectures to minimize technical debt.

  • Modern Architectures

    Liquid templates, Online Store 2.0 components, and native app blocks.

  • Shopify Functions & APIs

    Custom checkout validations, discounts, and backend automated workflows.

  • External Systems Sync

    GraphQL, custom webhooks, ERP integrations, and serverless middleware.

  • Optimized Performance

    Refactoring layout shifts, asset sizes, and redundant tracking scripts.

The Difference

Why ambitious brands scale with CartScaler

Shopify Plus Focused

Shopify Plus is at the core of what we do. We understand the platform's limits, capabilities and how to get the most out of it.

Business-aware

We don't ask 'what code should we write' first. We start with: 'what commercial outcome are we trying to achieve?'

Technical Depth

We write robust Liquid, use custom webhooks, work with GraphQL, write Shopify Functions, and integrate complex APIs.

Performance-conscious

We don't add apps to solve simple problems. We prefer native settings, configuration, and custom theme development.

Built to Maintain

We build clean code that doesn't break. Your in-house merchant team will still easily update sections six months later.

Long-term Partner

We act as your extended development team. We are committed to constantly improving and tweaking features post-launch.

How We Work

From ecommerce problem to production

01

Understand

We study your business, objectives, current storefront challenges, and target customer profiles.

02

Audit

We dive deep into your active theme code, apps list, pixel tracking scripts, and core web vitals.

03

Plan

We create a clear map detailing what should be configured natively, built custom, or completely removed.

04

Build

Our Shopify engineers write clean Liquid, CSS, and JS using modern best practices and minimal app overhead.

05

Test

Rigorous testing across desktop and mobile, checkout flows, variations, tracking scripts, and integrations.

06

Launch

Safe deployment with zero downtime, verified URL redirects, and immediate traffic monitoring.

07

Improve

Ongoing optimization of UX, page speed, customer conversion rates, and scaling capabilities.

About CartScaler

20+ years of engineering. Focused on ecommerce.

CartScaler is the ecommerce-focused practice of OpenCubicles Technologies — a software engineering team with over 20 years of experience building production systems across custom web applications, ERP, CRM, Applied AI, mobile platforms, and enterprise integrations.

Our ecommerce journey started almost when Shopify did. We worked with Magento for years — we appreciated the open-source flexibility — but as Shopify matured into a platform capable of handling serious ecommerce complexity, we made a deliberate decision: ecommerce, exclusively on Shopify.

That depth of broader engineering experience is what separates us. When a Shopify store needs a custom AWS Lambda integration, a machine-learning-assisted recommendation engine, a complex ERP data sync, or a serverless checkout validation — we have built those systems before, outside ecommerce.

20+ Years in TechnologyOpen Source RootsMagento → ShopifyERP & CRM SystemsApplied AIMobile Development
Our Engineering Background
  • Custom Applications & Platforms

    Over two decades building bespoke web applications, SaaS platforms, and enterprise software from scratch.

  • ERP, CRM & Business Systems

    Deep experience integrating and building systems that connect commerce operations to the wider business.

  • Applied AI & Machine Learning

    Practical application of AI in product recommendation, demand forecasting, and intelligent automation.

  • Mobile & Cross-Platform

    Native Android and iOS apps, plus hybrid PWA experiences connected to commerce backends.

  • Shopify — Exclusively for Ecommerce

    A deliberate, focused choice. We understand the platform deeply — its capabilities, its limits, and how to extend both.

Frequently Asked Questions

Everything you need to know about working with CartScaler on Shopify engineering.

No. A large part of our work involves improving existing Shopify stores, fixing technical issues, adding functionality, optimizing performance, or providing ongoing development.
Our primary focus is Shopify, but our commerce engineering background is broader. We have worked with large non-Shopify brands — including enterprise-scale Magento stores for well-known Indian fashion and lifestyle labels. Given Shopify's maturity, scalability, and ecosystem depth, we have concentrated our practice there, but we understand the broader commerce landscape well.
Yes. We specialize in complex Magento-to-Shopify Plus migrations. Our engineering team has deep expertise handling large catalog sizes, complex database schemas, multi-store configurations, and legacy third-party extension data. We coordinate the complete technical migration—including customer/order database mapping, custom metadata redirection, and SEO URL mapping—so you don't lose organic search ranking.
We do not offer direct CRO consulting or marketing strategy audits ourselves. Instead, we serve as the dedicated technology partner and engineering arm for renowned CRO specialists and design agencies. We take their designs, wireframes, and test concepts, and build them into highly optimized, high-performing storefront code.
Yes. We can work with existing Shopify themes, including Shopify's modern theme architecture, premium themes, and custom themes.
Yes. When a custom storefront is justified, we can build the experience around your brand and requirements.
Yes. We can evaluate whether the requirement is best handled through Shopify configuration, an app, theme development, Shopify Functions, APIs, a custom app, or another architecture.
Yes. We can work with advanced Shopify capabilities and more complex ecommerce requirements.
Yes. We can audit theme code, apps, scripts, tracking, images, and other sources of storefront speed overhead.
Yes. We work with APIs, GraphQL, webhooks, and third-party integrations.
Yes. We can work as an ongoing Shopify development partner after launch.
Yes. We can provide Shopify development capacity for agencies that need an experienced technical partner.