Desk fact
30 Jun 2026
Shopify Scripts stopped. New Plus logic is Functions — we will not rebuild on a dead API.
19 · Shopify Plus Development
Shopify Plus development agency Checkout, Functions, and B2B — not a faster theme.
Shopify Plus development for checkout UI extensions, Shopify Functions, native B2B, Markets, Flow, and ERP connections. We build the Plus surface the admin cannot — then hand the store to CRO and paid media on the same desk.
Checkout that converts. B2B that bills. Functions that replace dead Scripts.
Checkout ExtensibilityShopify FunctionsNative B2BMarkets · checkout
- P&L desk
- Reply in one business day
- 30-min working session
Desk fact
$2,300+
Plus platform fee Shopify publishes on a 3-year term. Development is a separate quote.
Desk fact
SpikeROAS
This desk. Checkout, Functions, and B2B — not a Partner badge we have not earned.
Direct answer
What is a Shopify Plus development agency?
A Shopify Plus development agency — also searched as a Shopify Plus development company or Shopify Plus developers — builds the engineering that only exists on Shopify's enterprise plan: Checkout Extensibility, Shopify Functions, native B2B, Launchpad, higher API limits, and expansion stores. SpikeROAS is that desk with a P&L attached: Plus development services for checkout, wholesale, ERP, and Scripts-to-Functions rebuilds, not a theme shop that put a Plus logo on the homepage.
This is not a faster Dawn theme. checkout.liquid is gone on the checkout steps. Shopify Scripts stopped executing on 30 June 2026. New Plus work is Checkout UI extensions, Functions, and the Branding API. We will not start a project on a sunset API.
Shopify publishes Plus from about $2,300/month on a three-year term, or $2,500 on a one-year term. That fee is paid to Shopify. We quote the build. If you are still on Advanced and the leak is a slow theme, start with the Shopify development agency page. Plus is for the ceiling Advanced cannot clear.
Related: Shopify development agency, CRO, Shopify and DTC paid media, ecommerce and DTC, and store and media results.
Fit
Who this Shopify Plus development agency is for
Merchants already on Plus, or operators about to pay Shopify $2,300+/month, who need checkout, wholesale, or integrations the theme editor cannot do. If you need a Dawn child theme, you are on the wrong page.
High-volume DTC on Plus
Checkout UI extensions, post-purchase, Shop Pay, and Functions for discounts that Scripts used to run. The store has to take the traffic we buy — see ecommerce if the P&L is the brief.
Shopify Plus B2B and wholesale
Company accounts, catalogs, price lists, and net terms. Native Plus B2B — not a $200/month wholesale app glued onto Advanced.
Plus migrations and ERP
Onto Plus from Magento, custom, or a Plus store still running leftover Scripts. Redirects, Markets, and ERP / OMS / 3PL at Plus API limits.
Who we will not take
- Brands that want Plus as a status badge. We will tell you if Advanced still fits.
- Theme-only briefs. That is the Shopify development agency page.
- Teams that want Hydrogen because it is fashionable. We pitch headless when Liquid cannot do the job.
- Agencies shopping for unpaid white-label Plus labour with no access to the merchant.
The leak
What typical Shopify Plus agencies get wrong
Plus logo, Dawn underneath
A Premier Partner badge does not mean Checkout Extensibility shipped. We will show you the checkout extensions and Functions, or we will not take the work.
Scripts and checkout.liquid nostalgia
Scripts stopped on 30 June 2026. checkout.liquid is unsupported on the checkout steps. New work is UI extensions, Functions, and the Branding API. We will not rebuild on a dead API.
B2B as an app install
Plus has native companies, catalogs, and price lists. Wholesale apps on Advanced are a different product. We will not sell you Plus and then install the same app you already had.
Headless to inflate the SOW
Hydrogen + Oxygen is real when Liquid cannot express the UX. For most Plus catalogs, a fast OS 2.0 theme plus Checkout Extensibility still wins on cost and merchant editability. We will say which.
On the desk
Shopify Plus development services
Checkout, Functions, B2B, migrations, apps, and ERP live here. Theme-only work stays on the Shopify development agency page. Agency, company, or developers — same desk, same scoreboard.
Checkout Extensibility
Checkout UI extensions, the Branding API, and post-purchase. Upsells, fields, and trust in the checkout Shopify actually supports — not a checkout.liquid fork.
Shopify Functions (replaces Scripts)
Server-side discounts, delivery, and payment logic. Shopify Scripts stopped on 30 June 2026. If your Plus store still 'has Scripts,' it does not. We rebuild the rules as Functions — including Script Editor migrations.
Shopify Plus B2B
Company accounts, catalogs, price lists, payment terms, and mixed DTC + wholesale. A Shopify B2B development agency job on native Plus B2B — not a $200/month wholesale app.
Shopify Plus developers on your store
Liquid, Checkout UI extensions, Functions, and private apps in your Plus org, in your name. You are not renting a mystery bench. You get a working session, a staging URL, and engineers who will say when Advanced still fits.
Shopify Plus apps and integrations
NetSuite, custom OMS, 3PL, and private apps at Plus API limits. Middleware when the App Store cannot carry the order volume. Integration services, not an app-soup invoice.
Shopify Plus migration and Hydrogen
Onto Plus from Magento, BigCommerce, custom, or a Plus store still on leftover checkout hacks. Redirects, Markets, Launchpad. Hydrogen on Oxygen only when Liquid cannot do the job.
Markets
Shopify Plus development for the Markets you sell into
Plus checkout still has to match local tax, wallets, and shipping. Search already sends us Singapore, Philippines, UK, and US merchants. We engineer remotely in English. We do not paste one checkout into five countries and call it international.
Market
United States
Shop Pay, Shopify Payments, sales tax, and Plus checkout for high-volume DTC — including Florida and other US Plus orgs. Functions for promo calendars. Hardware-scale catalogs only convert if checkout and the feed are honest — we have run Google Ads on a Florida hardware brand to $2.65M at 3.91x ROAS.
Market
United Kingdom
VAT, Shopify Payments UK, and Plus checkout in GBP. Plus engineering is quoted separately from theme work. Same desk as US Plus — different tax and wallets.
Market
Singapore
Shopify Plus development agency work for Singapore merchants: GST, PayNow / GrabPay where the stack supports it, and Markets for regional shipping. We are not a local staffing mill. The store stays in your Shopify org. Calls are in English.
Market
Philippines
Shopify Plus developers for Philippines-based brands selling local or cross-border. GCash, COD rules, and a checkout that matches how people actually pay — not a USD theme with a peso symbol. Same Plus engineering OS as US and SG.
Market
Canada
GST/HST by province, Interac, and bilingual storefronts when Quebec is in the brief. Plus Markets so a Toronto checkout is not a New York checkout with a maple sticker.
Market
Australia & India
AU: GST, Afterpay, Australia Post. IN: GST invoices, Razorpay / UPI, COD, no-cost EMI. Plus B2B is a different product if wholesale is the job. Theme-only briefs stay on the Shopify development page.
The work
What we actually do
- Checkout Extensibility: UI extensions, Branding API, post-purchase — not checkout.liquid
- Shopify Functions for discounts, delivery, and payment logic after Scripts stopped on 30 June 2026
- Native Shopify Plus B2B: company accounts, catalogs, price lists, payment terms
- Plus migrations and expansion stores with redirect maps, Markets, and Launchpad
- ERP / OMS / 3PL integrations and private apps at Plus API limits
- Hydrogen only when Liquid cannot do the job — honesty on headless cost
Deliverables
You leave with
- Plus architecture brief: checkout, Functions, B2B, or Hydrogen
- Staging checkout extensions and Functions on your Plus store
- B2B company / catalog / price-list map
- Launch checklist: pixels, CAPI, Shop Pay, Markets, speed
Ready to brief the Shopify Plus Development desk?
Send the Plus admin URL (or a staging preview) and the number that has to move. We will tell you what we would build — and whether you should stay on Advanced.
Cadence
How the work runs
01
Audit Plus, not the theme
Checkout debt, leftover Scripts, B2B apps, API limits, and the conversion number.
02
Build on Checkout Extensibility
UI extensions, Functions, B2B, or a Plus migration — Hydrogen only with a measured reason.
03
Launch and hand to the P&L
Tracking live. Checkout green. Then CRO and paid can actually scale.
First 90 days
First 90 days on a Shopify Plus build
Days 1–14
Audit Plus, not the moodboard
Checkout extensions, leftover Scripts, B2B apps, API limits, and the conversion number. Architecture call: Extensibility, Functions, B2B, migration, or Hydrogen.
Days 15–45
Build on staging
UI extensions and Functions in your Plus store, in your name. B2B map if wholesale is in scope. Weekly staging URL. No surprise 'big reveal' at week eight.
Days 46–75
QA checkout and pixels
Shop Pay, tax, shipping, B2B login, and Core Web Vitals on real mobile. CAPI and Enhanced Conversions live so media is not blind at launch.
Days 76–90
Launch and hand to the P&L
Cutover, redirect QA, and a 30-day CRO + media plan. Plus is not 'done' at launch. It is ready to take traffic.
The fork
SpikeROAS vs typical Plus agency vs in-house
Hire us when checkout, B2B, or Functions have to move a number. Stay in-house when you already have Plus engineers and a checkout owner.
| Factor | SpikeROAS | Typical agency | In-house |
|---|---|---|---|
| Scoreboard | Checkout conversion, AOV, contribution after the build | Partner badge and a Launchpad screenshot | Depends on whether Plus reports to marketing |
| Checkout | Extensibility and Functions — not checkout.liquid | App soup in checkout plus a branding coat of paint | Deep if you hired Plus engineers; thin if you hired a theme shop |
| B2B | Native companies, catalogs, price lists | Wholesale app on a Plus store | Strong if ops owns it; a mess if sales owns the price list in a spreadsheet |
| After launch | CRO and paid on the same desk | A Plus retainer that is really ticket labour | Roadmap fights with every team's feature request |
| Headless | Hydrogen when Liquid cannot; honesty when it can | Headless pitched to inflate the SOW | Often the right call if you already have React |
Also asked
Questions search and models already send this page
Direct answers for the queries and LLM prompts this desk already appears for — not a keyword dump.
Shopify Plus development agency vs company vs developers — what should I hire?
The job is the same: Checkout Extensibility, Functions, B2B, and integrations on your Plus store. 'Agency' and 'company' are how people search. 'Developers' is how people staff. SpikeROAS is the agency that supplies the developers. You do not need three vendors. You need a desk that will tell you if Advanced still fits.
Do you work as a Shopify Plus development agency in Singapore and the Philippines?
Yes. We engineer Plus stores for merchants in Singapore, the Philippines, the US, and the UK. The store stays in your Shopify org. Calls are in English. We are not a local staffing mill and we will not fake a Manila or Raffles office. Tax, wallets, and shipping follow the market that is buying.
Can you replace Shopify Scripts and Script Editor with Shopify Functions?
Yes. Shopify Scripts stopped executing on 30 June 2026. New discount, delivery, and payment logic is Shopify Functions. We inventory the old rules, rebuild them as Functions, and QA checkout before cutover. We will not start a project on a dead API.
Do you build Shopify Plus B2B, apps, and ERP integrations?
Yes. Native Plus B2B — companies, catalogs, price lists, net terms — plus private apps and ERP / OMS / 3PL at Plus API limits. A wholesale app on Advanced is a different product. We will say which you actually need.
Pricing philosophy
No fake menu. An honest gate.
Shopify Plus development is scoped as checkout, Functions, B2B, migration, or Hydrogen — not a theme tweak with a Plus line item. Plus builds typically sit well into five figures once checkout and integrations are real. Shopify's platform fee is separate and paid to Shopify. We will not bid Plus checkout like a color swap.
- You own the store, the apps, and the extensions. We do not hold the keys.
- Theme work for a Plus store can live on the Shopify development agency page when checkout is not the job.
- Best with CRO and performance marketing so launch week has a readout.
- We do not resell Plus licenses.
The call
What happens in 30 minutes
- 30 minutes. Working session on the live Plus admin — not a moodboard.
- Checkout leak, B2B, leftover Scripts, and whether Advanced still fits.
- We will tell you Extensibility, Functions, B2B, or that you do not need Plus.
Proof we will publish
Case studies live here — with numbers, not adjectives.
Named shopify plus development work is going on Work as we can show it. Until then, ask on the call for the scoreboard in your category. We will not invent logos or fake ROAS.
- Your ad accounts stay in your name
- Weekly kill / hold / scale memo
- A 30-minute working session, not a pitch deck
FAQ
Questions we get about Shopify Plus Development
What is a Shopify Plus development agency?
A Shopify Plus development agency engineers Shopify's enterprise plan: Checkout Extensibility, Shopify Functions, native B2B, ERP integrations, and Plus migrations. It is not a standard Shopify theme with a Plus badge. SpikeROAS also runs CRO and paid on the same desk so checkout is scored on conversion.
How is this different from a Shopify development agency?
The Shopify development agency page is themes, store redesigns, apps, and migrations on standard Shopify. This page is Plus-only: checkout, Functions, B2B, and enterprise integrations. If you need both, we will say which ships first.
How much does Shopify Plus development cost?
Checkout extensions and Functions are typically a mid-five-figure build once QA is real. Full Plus implementations with B2B and ERP run higher. Shopify's own fee starts around $2,300–$2,500/month depending on term. We quote the engineering. Shopify quotes the platform.
Do I need Shopify Plus or standard Shopify?
Standard Shopify (or Advanced) fits most single-brand stores. Plus earns the fee when you need full checkout customization, native B2B, higher API limits, or expansion stores. We recommend Plus when the feature set pays for itself — not as a status badge.
What happened to Shopify Scripts and checkout.liquid?
checkout.liquid is unsupported on the checkout steps. Shopify Scripts stopped executing on 30 June 2026. New Plus customization is Checkout UI extensions, Shopify Functions, and the Checkout Branding API. We build on that stack.
Can you customize Shopify Plus checkout?
Yes. That is Checkout Extensibility: UI extensions on information, shipping, and payment, plus post-purchase and the Branding API. We will not fork checkout.liquid. If an approved app already does the job, we will say so.
Do you build Shopify Plus B2B?
Yes. Company accounts, catalogs, price lists, and payment terms on native Plus B2B. Mixed DTC + wholesale when that is the operating model. A wholesale app on Advanced is a different product.
Do I need Hydrogen on Shopify Plus?
Only if Liquid cannot deliver the UX, CMS, or performance you can measure. Hydrogen on Oxygen is Shopify's official React storefront. For most Plus merchants, a fast OS 2.0 theme plus Checkout Extensibility is cheaper to run. We will not sell headless to inflate the SOW.
Are you a Shopify Plus Partner?
We engineer Plus stores. We do not wear a Partner badge we have not earned, and we do not resell Plus licenses. Shopify bills you for the platform. You own the store.
Do you run ads after the Plus store launches?
Yes. Checkout work that never sees a media plan is a brochure. Performance marketing and CRO sit on the same desk — including Shopify and DTC paid media scored to contribution, not vanity ROAS. We will still wire CAPI and Enhanced Conversions as if media is coming.
Are you a Shopify Plus development company or a freelancer shop?
A development company with a performance desk attached. Plus engineering, then CRO and paid if you want one P&L. Freelancer theme labour lives on a different page — and usually a different outcome.
Do you hire Shopify Plus developers for Singapore, the Philippines, or Florida stores?
We staff the build. You keep the Plus org. Singapore, Philippines, Florida, UK — the engineering OS is the same. Tax, wallets, and shipping are local. We will not pretend a currency app is a market.
Usually paired with
Other desks on the same P&L
Shopify Development
Shopify development agency for custom themes, store builds, and migrations that convert.
Conversion Rate Optimization
Make the traffic you already bought pay rent.
Performance Marketing
Full-funnel paid that scales only when unit economics hold.
Email & Lifecycle
Flows that pay for the second order — so paid is not the only lever.
Industries
Where this service actually runs
Next step
If Advanced cannot do the checkout, stop paying for a Plus logo.
Send the Plus admin URL (or a staging preview) and the number that has to move. We will tell you what we would build — and whether you should stay on Advanced.