Shopify checkout extension development and Functions
Customize Shopify checkout the supported way. We build checkout UI extensions and Shopify Functions that add fields, offers and rules to your checkout, and move old checkout.liquid code to checkout extensibility.
- Checkout UI extensions and post-purchase offers
- Discount, delivery and payment Functions
- Built by a team that ships checkout features in its own apps
Built by the team behind 4 Shopify apps rated 4.7★ across 522 reviews
What we can add to your checkout
Checkout is where small changes move revenue the most. These all run on Shopify’s supported extension points.
Upsells and offers
Product offers in checkout and on the thank-you page.
Custom fields
Gift messages, delivery instructions, tax IDs or PO numbers saved to the order.
Consent and age checks
Terms checkboxes and age confirmation at checkout, like our AVP and TC apps.
Custom discounts
Tiered, bundle and customer-specific discounts with Shopify Functions.
Delivery and payment rules
Hide, rename or reorder shipping and payment methods by cart, customer or location.
checkout.liquid upgrade
Rebuild old checkout.liquid customizations as extensions before they stop working.
Who this is for
Most checkout customization needs Shopify Plus. Functions for discounts work on every plan.
How a project runs
You always know what’s being built, what it costs and when it ships.
Checkout audit
We review your current checkout, scripts and apps and list what can move to extensions.
Proposal
Extensions, Functions, price and timeline in writing.
Build and test
Extensions run on a development store with test orders before anything touches live checkout.
Launch
We publish to your live checkout and watch orders closely after release.
How checkout projects are priced
Checkout work is scoped after a short audit. A single extension or Function is a small project. Full checkout.liquid migrations are priced by how much custom code exists today.
What changes the price
- Number of extensions and Functions
- Amount of checkout.liquid code to replace
- Data that must be saved to orders or metafields
- Admin settings your team needs
- Testing across markets and payment methods
What we work with
Proof you can install today
Most agencies show screenshots. We show apps on the Shopify App Store that merchants use and review every week.
Checkout extension questions
What are Shopify checkout UI extensions?
They are small apps that add content and fields to supported places in Shopify checkout, like the order summary or thank-you page, without editing checkout code.
Do I need Shopify Plus to customize checkout?
Checkout UI extensions in the information, shipping and payment steps need Shopify Plus. Shopify Functions for discounts, and thank-you page extensions, work on other plans too.
How do I move from checkout.liquid to checkout extensibility?
We list every customization in your checkout.liquid and scripts, rebuild each one as an extension, Function or app setting, test it on a development store and then switch over.
What can Shopify Functions customize?
Discounts, shipping and payment method rules, cart and checkout validation, and order routing, among others.
Can extensions add upsells or custom fields?
Yes. Product offers, gift messages, delivery notes and custom inputs saved to the order are common extensions.
Is checkout extensibility secure?
Yes. Extensions run in Shopify’s sandbox and can’t touch card data, so checkout stays PCI compliant.
Related services
Need your checkout to do more?
Tell us what you want to change and we’ll scope it after a quick audit.