Shopify development services, starting with the checkout deadline that will not wait for you
Legacy checkout code is being switched off in stages and the last one lands on 26 August 2026. After it, Shopify removes what is left and moves your store to the standard configuration. Merchants who left this late have reported meaningful conversion damage on the way through.
Checkout extensibility migration, custom functionality, app extensions and theme work built to survive the next platform change too.
What are Shopify development services?
Shopify development services cover the code layer of a Shopify store: theme development in Online Store 2.0, custom sections and functionality, app extensions, third party integrations, and migrating legacy checkout customisation onto the checkout extensibility framework of UI extensions, Functions, the branding API and web pixels.
For most merchants right now, one of those items is urgent and the rest can wait.
So this page starts with the deadline, then covers everything else Shopify development services actually involve.
The checkout deadline, in plain terms
Three dates, two of which have already gone. If your store still relies on any of this, the work is now overdue rather than upcoming.
28 August 2025: the Thank you and Order status pages went first. checkout.liquid and additional scripts stopped applying there. Anything you had running on post purchase pages, tracking, upsells, referral widgets, has not been firing for a year unless it was rebuilt.
30 June 2026: Shopify Scripts stopped. Scripts had been running alongside Extensions during the transition and that period ended. Discount logic, shipping rules and payment customisation that lived in Scripts needs to be Shopify Functions now.
26 August 2026: the Additional Scripts field stops firing. This is the one still ahead. Any JavaScript sitting in that field goes inert, and Shopify removes legacy checkout code and upgrades the store to the standard configuration automatically. It is not an opt in.
Leaving it to the automatic upgrade is the expensive route. Agencies working on late migrations have reported conversion drops of up to around 14% where customisation disappeared without a replacement, and project costs ranging from roughly $8,000 to $60,000 depending on how much lived in the old checkout. Doing it deliberately costs less than having it done to you.
Shopify publishes and occasionally revises these dates, so confirm the current position for your plan before scheduling work. If you are on Plus, enforcement has been running ahead of the non-Plus timeline.
What replaced what
checkout.liquid was one file doing everything. It has been split into four building blocks, each owning a slice of what it used to cover.
| You used to use | You now use | For |
|---|---|---|
| checkout.liquid layout | Checkout UI extensions | Anything you want to appear or change in the checkout interface |
| Shopify Scripts | Shopify Functions | Discount, shipping and payment logic, running server side in a sandbox |
| Liquid styling in checkout | Branding API | Colours, typography and layout tokens, without touching markup |
| Additional Scripts field | Web pixels, under Customer Events | Analytics, tracking and third party tags |
| Post purchase Liquid | UI extensions on those pages | Upsells, referrals and anything on Thank you or Order status |
Functions run in a sandboxed server side environment and are written in JavaScript or Rust. That is a genuine improvement on Scripts for reliability, and it does mean the migration is a rebuild rather than a copy and paste.
What our Shopify development services cover
The checkout work is the current priority. The rest is what a Shopify store needs from a developer in an ordinary year.
Checkout extensibility migration
Auditing what your legacy checkout actually does, then rebuilding it as UI extensions, Functions, branding and pixels before the automatic upgrade decides for you.
Theme development
Built in Online Store 2.0 with proper sections and blocks, so your team can rearrange pages without a developer and updates do not overwrite your work.
Custom sections and functionality
The things the theme does not do: configurators, bundles, conditional fields, custom product logic. Built as reusable sections rather than hard coded into one page.
App extensions and integrations
Connecting Shopify to your ERP, PIM, warehouse or accounting system, and building app extensions where an off the shelf app does not fit.
Shopify Functions
Discount, shipping and payment customisation rebuilt properly, including the cases where merchants had layered several Scripts that contradicted each other.
Metafields and metaobjects
Structured content modelled properly so product data lives in fields rather than in the description, which makes everything downstream easier.
Markets and multi-currency
Selling into more than one country without duplicating stores, with pricing, tax and language handled at the platform level.
App audit and removal
Most stores carry apps nobody uses that still load scripts on every page. Removing them is development work with an immediate speed return.
Headless where it earns it
Hydrogen and a custom storefront are right for a minority of merchants. We will tell you honestly whether you are in that minority.
The app audit card pays back fastest on most stores. Our bulk PageSpeed checker will show you what your key templates currently cost a shopper on a phone.
How a checkout migration runs
Inventory what the old checkout does
Every script, tweak and tag, including the ones added years ago by someone who has left. You cannot rebuild what nobody has written down, and this step is where the surprises are.
Decide what deserves rebuilding
A meaningful share of legacy customisation is dead code, duplicated tracking or a feature nobody uses. Migrating all of it is the expensive way to reach the same place.
Rebuild on the new framework
UI extensions for interface, Functions for logic, branding API for styling, web pixels for tracking. Built and tested in a preview before anything touches the live checkout.
Ship and watch conversion
Released with checkout conversion monitored daily for the first fortnight, because this is the one part of the store where a quiet regression is genuinely expensive.
What Shopify development is for the rest of the time
Once the checkout is dealt with, development work on a Shopify store tends to fall into these.
Making the theme editable
Converting hard coded pages into Online Store 2.0 sections so marketing can build a landing page without booking developer time.
Selling things Shopify does not sell natively
Bundles, subscriptions with custom rules, made to order configurators, quantity breaks. Usually an app plus glue code rather than either alone.
Connecting the back office
Stock, orders and customers moving between Shopify and whatever runs your operations, so nobody is exporting a spreadsheet twice a week.
Undoing accumulated weight
Years of apps, snippets and abandoned experiments left in the theme. Removal is unglamorous and it is often the biggest single speed win available.
Opening new markets
Markets, currencies, translated content and local payment methods, configured once rather than by cloning the store per country.
Keeping up with platform changes
Checkout extensibility is not the last deprecation Shopify will ship. Building on supported patterns is what stops this being a crisis every two years.
When you do not need a Shopify developer
Development is the most expensive way to solve a Shopify problem, so it is worth checking it is the right one.
When a well built app already does it. Custom code you own is code you maintain forever. If a supported app covers ninety percent of the requirement, taking the ninety percent is usually the better business decision than building the hundred.
When the problem is the theme, not the platform. Plenty of requests that arrive as custom development turn out to be a theme setting, a collection structure or a merchandising decision. We will say so, even though it is a smaller invoice.
When headless is being considered for the wrong reason. Hydrogen and a custom storefront genuinely suit some merchants. They also add cost, complexity and a permanent dependency on developers for things that used to be a click. Speed alone is rarely a sufficient reason, because most slow Shopify stores are slow from apps rather than from Liquid.
The checkout migration is the exception to all of this. That one is not optional and it has a date on it.
How much do Shopify development services cost?
Priced per project with a scope, because open ended development retainers reward slowness.
Checkout audit
What your legacy checkout does, what needs rebuilding, what is dead code, and what the migration actually involves. Free, and useful even if you hand it to another developer.
Migration project
Rebuild on the extensibility framework, tested in preview and monitored after launch. Fixed scope and fixed price, quoted after the audit.
Development retainer
Ongoing theme, section and integration work for merchants who need regular capacity. Monthly, cancellable, with the backlog visible to you.
Published migration costs have ranged widely, from a few thousand for a light store to tens of thousands where years of checkout customisation had accumulated. The audit is what turns that range into a number for your store, which is why it comes first and why it is free.
Development alongside the rest of the store
Shopify speed optimization
App weight and render blocking scripts. Most slow Shopify stores are slow from what has been installed rather than from the theme itself.
See speed work →Shopify SEO services
Collection architecture and the duplicate URLs Shopify generates by default. Development decisions constrain what SEO can fix later.
See Shopify SEO →Shopify Plus development
For merchants on the enterprise plan, where checkout enforcement arrived earlier and B2B and multi-store add their own requirements.
See Plus development →Common questions about Shopify development
Shopify removes the legacy checkout code and upgrades your store to the standard configuration automatically. Nothing asks your permission first. Whatever your old checkout did that has not been rebuilt simply stops existing, which is why agencies handling late migrations have reported conversion damage of up to around 14%. The store keeps working, it just stops doing the things you had customised.
Four things, each covering a slice of what one file used to do. Checkout UI extensions for anything in the interface, Shopify Functions for discount, shipping and payment logic, the branding API for styling, and web pixels under Customer Events for analytics and tags. It is a rebuild rather than a copy across, because the model is genuinely different.
No. Scripts ran alongside Extensions during the transition and that period ended on 30 June 2026. Anything that lived in Scripts, typically discount logic, shipping rules or payment customisation, needs to be a Shopify Function now. Functions run server side in a sandboxed environment and are written in JavaScript or Rust.
Web pixels, under Settings then Customer Events. The Additional Scripts field is deprecated and any JavaScript left in it stops firing on 26 August 2026. This catches people out because tracking tends to be set up once and never revisited, so the tags keep reporting right up until the day they do not.
Reported project costs have ranged from roughly $8,000 to $60,000, driven almost entirely by how much customisation had accumulated in the old checkout rather than by store size. A store with a couple of tracking tags is a small job. A store with years of layered scripts, custom discount logic and post purchase widgets is not. An audit turns that range into a number.
Probably not, and we will say so if that is the honest answer. Headless suits merchants with genuinely unusual front end requirements or a content heavy experience Liquid cannot serve. It adds cost, complexity and a permanent developer dependency for things that used to be a click in the theme editor. If the motivation is speed, the cheaper fix is almost always removing apps.
Yes, and on plenty of projects that is the fastest route. Your developers know the codebase, so we scope and specify the checkout migration and they implement, with the result reviewed rather than assumed. We are equally happy doing the build ourselves. The deadline does not care which of us does it.
Find out what your old checkout is still doing
We will inventory every script, tweak and tag in your legacy checkout, tell you which of it is dead code and which genuinely needs rebuilding, and give you a scope and a number. Given the date, this is worth knowing this week rather than in three weeks. No obligation, no sales pitch.
Get my free checkout audit- Legacy code inventory
- Rebuild or retire
- Scope and cost