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Conversion

Shopify Plus Agency · USA

The Shopify Plus agency for brands that outgrew their stack

Checkout extensibility, Shopify Functions, B2B + DTC from one instance, multi-store expansion, and ERP integration — engineered by a US-based Shopify Plus Partner since 2019.

  • Shopify Plus Partner since 2019 · direct line to launch engineers
  • Checkout extensibility + Shopify Functions shipped in production
  • B2B + DTC from a single Plus instance
  • Pay-on-results growth model after launch
Conversion service illustration in brand blue and green

Conversion in numbers

200+

Stores launched

Since 2019

Plus Partner

+38%

Avg conversion lift

1.4s

Median LCP

About our Plus practice

A Shopify Plus development company that ships the hard parts

Shopify Plus Partner

Since 2019

Founded 2018

8 years building Shopify

200+ Brands Launched

DTC & B2B

San Francisco, USA

In-house team

Conversion is a Shopify Plus development agency headquartered in San Francisco. Since 2019 we've been a Shopify Plus Partner, building enterprise storefronts for DTC and B2B brands across the US, Canada, UK, and Australia — checkout extensibility, Shopify Functions, wholesale catalogs, multi-store international expansion, and replatforms from Magento, Salesforce Commerce Cloud, and WooCommerce.

Plenty of agencies sell 'Shopify Plus services' and have never shipped a Checkout UI Extension or a delivery-customization Function. We build the parts of Plus that actually justify its price tag — the checkout, the automation layer, the B2B engine — and every build ships with an experimentation harness and a 90-day optimization roadmap.

Why Plus projects stall

Most agencies sell Plus. Few can build it.

We've rescued dozens of stalled Plus projects. The failure patterns are consistent — and avoidable.

Plus features left on the shelf

Brands pay for Plus and use it like standard Shopify — no checkout extensibility, no Functions, no Flow automations, no B2B catalogs. You're paying an enterprise license for a theme install. We build the features that justify the tier.

Checkout treated as untouchable

The checkout is where money is won or lost, and most agencies won't touch it. Checkout UI Extensions, Branding API, and Functions let us add upsells, trust content, custom fields, and bespoke discount logic — measured with A/B tests, not opinions.

B2B bolted on with apps

Wholesale run through duct-taped apps and duplicate stores creates catalog drift and support chaos. Plus-native B2B — company accounts, price lists, net terms, quote-to-order — runs both channels from one instance with one source of truth.

Paying for Plus but running it like standard Shopify?

Book a free 30-minute Plus audit. We'll show you exactly which Plus capabilities you're paying for and not using — and what each is worth in revenue.

30-minute call · No commitment · Custom quote in 48 hours

Shopify Plus development services

Everything the Plus tier can do, put to work

Full-service Shopify Plus development — from checkout extensibility to B2B to multi-store international expansion. We work in Liquid, TypeScript, React, Remix, and the full Plus API surface.

Checkout Extensibility

Custom checkout built on Checkout UI Extensions, the Branding API, and Shopify Functions. Upsells, trust content, custom fields, address validation, and delivery logic inside the highest-converting checkout on the internet.

  • Checkout UI Extensions
  • Branding API design systems
  • Post-purchase extensions
  • A/B tested checkout upsells

Shopify Functions

Custom backend logic without apps: discount stacking rules, delivery and payment customization, cart validation, and B2B pricing engines — deployed as Functions with full CI/CD.

  • Discount + promotion logic
  • Delivery customization
  • Payment customization
  • Cart + checkout validation

B2B & Wholesale on Plus

Plus-native B2B: company accounts, customer-specific catalogs and price lists, quantity rules, net-terms payment, and quote-to-order workflows — running DTC and B2B from a single instance.

  • Company accounts + locations
  • Price lists + quantity rules
  • Net terms + payment terms
  • Quote-to-order workflows

Multi-Store & International

Expansion stores, Markets Pro, multi-currency, localized checkout, hreflang, and geo-routing. One brand, many markets — without catalog drift or SEO cannibalization.

  • Up to 9 expansion stores
  • Markets Pro + multi-currency
  • hreflang + geo-routing
  • Localized content + checkout

Migrations to Shopify Plus

Replatforming from Magento 1 & 2, Salesforce Commerce Cloud, WooCommerce, BigCommerce, and Shopware. Catalog, customer, and order history migration with zero-ranking-loss SEO preservation.

  • Magento → Plus
  • SFCC (Demandware) → Plus
  • One-to-one 301 mapping
  • 90-day GSC monitoring

ERP, PIM & 3PL Integration

NetSuite, SAP, Microsoft Dynamics, Akeneo, Salsify, ShipBob, and custom middleware. Real-time inventory, order sync, and financial reporting that survives an audit.

  • NetSuite + SAP + Dynamics
  • PIM (Akeneo, Salsify)
  • 3PL + WMS integration
  • Custom middleware (Node/TypeScript)

Flow & Launchpad Automation

Shopify Flow automations for fraud, tagging, inventory, and VIP workflows. Launchpad for scheduled drops, flash sales, and BFCM — tested and rehearsed before the traffic spike.

  • Flow automation library
  • Launchpad drop scheduling
  • Fraud + risk workflows
  • BFCM load rehearsal

Performance & CRO on Plus

Core Web Vitals engineering at the theme level, experimentation harness setup, and a post-launch CRO roadmap. Plus stores we build ship with sub-1.5s LCP medians.

  • Core Web Vitals greens
  • A/B testing harness
  • Post-launch CRO roadmap
  • Pay-on-results growth option

Our Plus delivery process

From scoping to launch in 12–20 weeks

Conversion's four-stage growth process visualized in brand blue and green
01

Discovery & fixed-scope quote

30-minute discovery call, technical audit of your current stack, and a fixed-scope quote within 48 hours. You get a week-by-week roadmap before you sign anything.

02

Architecture & design

Data model, integration map, checkout extension plan, and conversion-led design. Every template is tied to a conversion hypothesis with a measurable lift target.

03

Build & integrate

Theme or headless build, Functions and checkout extensions, B2B configuration, ERP/PIM hookups, and migration dry runs — with weekly status calls and a shared sprint board.

04

Launch & compound

Zero-downtime cutover, 301 verification, 90-day Search Console monitoring, and a post-launch CRO program. Most clients move to pay-on-results growth from here.

Your options compared

Freelancer vs generalist vs Plus specialist

What you actually get at each tier — from the team that inherits the projects when the cheaper options stall.

FeatureFreelancerGeneralist agencyConversion (Plus specialist)
Shopify Plus Partner status—Sometimes✓
Checkout UI Extensions shipped—Rarely✓
Shopify Functions in production—Rarely✓
Plus-native B2B builds—Rarely✓
ERP / PIM integration depthBasicVariesNetSuite, SAP, Dynamics
Zero-loss SEO migrations—Sometimes✓
Post-launch CRO program—Extra costPay-on-results

Shopify Plus case studies

Enterprise builds. Measured results.

Shopify Plus — Home goods

+38%

conversion rate

Magento 2 to Plus replatform with checkout extensibility

“The migration was flawless — zero ranking loss, and the new checkout extensions lifted completion 12% in the first month. Night and day from our last agency.”

Shopify Plus — Industrial supplies

B2B + DTC

one Plus instance

Wholesale moved off a legacy portal onto Plus company accounts

“Our reps used to key orders into a 2009-era portal. Now wholesale buyers self-serve with their own price lists and net terms. B2B revenue is up 61% year over year.”

Shopify Plus — Beauty

9 markets

one brand

International expansion with Markets Pro and localized checkout

“We went from a single US store to nine localized markets in seven months. Currency, language, duties, checkout — all handled. International is now 34% of revenue.”

Why Conversion

The Plus partner brands switch to

Plus Partner since 2019

Direct access to Shopify's launch engineers, early access to Functions, checkout extensibility, and Commerce Components. Your build benefits from the roadmap before it ships publicly.

We build the hard parts

Checkout UI Extensions, Shopify Functions, B2B engines, ERP middleware. The features that justify the Plus license — shipped in production, not listed on a slide.

Fixed scope, week-by-week roadmap

A fixed-price quote within 48 hours of discovery, a published week-by-week roadmap on day one, and a weekly status call for the duration. No hourly-billing black holes.

Zero-loss migrations

80+ replatforms with one-to-one 301 mapping, structured data preservation, and 90-day Search Console monitoring. Zero ranking loss is the bar — and the metric we report against.

Conversion-led, not portfolio-led

Every template ships tied to a conversion hypothesis. In-house designers, Liquid devs, React engineers, and CRO analysts in one room — no subcontracting.

Pay-on-results after launch

Post-launch growth work runs on our pay-on-results model: fees track incremental revenue, not a flat retainer. Skin in the game on the number you care about.

Frequently asked

Shopify Plus agency questions

What is a Shopify Plus agency?
A Shopify Plus agency is a development and growth partner that specializes in Shopify's enterprise tier. Beyond standard theme work, a Plus agency builds checkout extensibility (Checkout UI Extensions and the Branding API), Shopify Functions for custom discount/delivery/payment logic, B2B and wholesale catalogs with company accounts, multi-store and multi-currency expansion with Markets Pro, Launchpad automations, and ERP/PIM/3PL integrations. Conversion has been a Shopify Plus Partner since 2019 with direct access to Shopify's launch engineers.
How much does a Shopify Plus development company charge?
In the US market, Shopify Plus builds typically run $50K–$250K+ depending on scope: checkout extensibility, custom Functions, B2B catalogs, number of expansion stores, and ERP/PIM integrations are the main cost drivers. A focused Plus theme rebuild starts around $30K–$50K. Migrations to Plus from Magento or Salesforce Commerce Cloud typically run $40K–$120K. We scope fixed-price after a 30-minute discovery call and deliver a quote within 48 hours.
Is Shopify Plus worth it for my brand?
Shopify Plus makes financial sense once you're processing roughly $1M+ GMV annually, running B2B alongside DTC, expanding internationally, or need custom checkout logic. Plus unlocks checkout extensibility, Shopify Functions, Flow automations, Launchpad, up to 9 expansion stores, B2B company accounts, and dedicated APIs with higher rate limits. Below that threshold, a well-built standard Shopify store usually delivers better ROI — and we'll tell you that on the first call if it's true for you.
How do I choose between Shopify Plus development companies?
Verify Shopify Plus Partner status on the official Shopify Partner Directory, ask for case studies with real revenue and Core Web Vitals metrics, confirm the team is in-house (not subcontracted offshore), and ask specifically about checkout extensibility and Shopify Functions experience — many 'Plus agencies' have never shipped either. Ask to speak to two current clients at your GMV stage. We'll connect you to ours on the first call.
Can you migrate us to Shopify Plus from Magento, Salesforce Commerce Cloud, or WooCommerce?
Yes. We've migrated 80+ stores to Shopify and Shopify Plus from Magento 1 & 2, Salesforce Commerce Cloud (Demandware), WooCommerce, BigCommerce, Shopware, and custom builds. Every Plus migration includes catalog and customer/order history mapping, one-to-one 301 redirects, structured data preservation, ERP re-integration, and 90 days of post-launch Search Console monitoring. Zero ranking loss is the bar we report against.
Do you build B2B and wholesale on Shopify Plus?
Yes — B2B on Plus is one of our core practices. Company accounts, customer-specific catalogs and price lists, quantity rules, net-terms payment, quote-to-order workflows, and B2B checkout customization via Functions. Most engagements run DTC and B2B from a single Plus instance so you get one stack, one catalog, and one reporting layer.
What is checkout extensibility and why does it matter?
Checkout extensibility is Shopify Plus's framework for customizing checkout with Checkout UI Extensions, the Branding API, and Shopify Functions — replacing the deprecated checkout.liquid. It lets you add trust badges, upsells, custom fields, address validation, and custom discount or shipping logic inside the world's highest-converting checkout without forking it. Checkout customizations typically lift checkout completion 5–15% when driven by A/B test data.
Do you provide ongoing support after a Shopify Plus launch?
Yes. Most Plus clients move into a growth retainer covering CRO experiments, performance optimization, seasonal readiness (BFCM, Q4), Functions and app maintenance, and new-market expansion. Our pay-on-results option ties fees to incremental revenue — you pay as the store grows, not a flat retainer.

Related services

More ways we grow Shopify brands

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Custom Shopify theme builds, redesigns, and full-stack development for stores on any Shopify plan.

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Shopify Migration Agency

Zero-ranking-loss replatforms from Magento, WooCommerce, BigCommerce, and Salesforce Commerce Cloud.

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Shopify B2B Development

Plus-native wholesale: company accounts, price lists, net terms, and quote-to-order workflows.

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Shopify SEO Agency

Technical SEO, collection page optimization, content, links, and AI search (GEO) for Shopify stores.

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Ready to use what you're paying for?

Put the Plus in your Shopify Plus

Book a free 30-minute scoping call. We'll audit your current Plus setup (or migration path), identify the unused capabilities worth the most revenue, and deliver a fixed-scope quote within 48 hours.

No credit card · No commitment · Pay only on results