Best custom checkout apps for Shopify in 2026

Last updated: October 15, 2026. Pricing and ratings are taken from each app's Shopify App Store listing on that date.

Quick answer: the best custom checkout app depends on whether you're customizing fields or selling. UpsellPlus combines checkout upsells with checkout customizations, cart and post-purchase offers from $119/month on Shopify Plus. Checkout Blocks is Shopify's free option, and Checkout Buddy and Checkout Plus are cheaper field tools. All in-checkout changes need Shopify Plus.

Disclosure: UpsellPlus is our app. Competitor facts are taken from each app's Shopify App Store listing, and we say where each one is the better fit.

Best custom checkout apps for Shopify in 2026 compared

"Not listed" means the feature isn't shown on the app's Shopify App Store page.

What can a custom checkout app change?

On Shopify Plus, checkout apps can add custom fields, trust badges, messages, upsell offers and gift options inside checkout, and rename, reorder or hide payment and delivery methods. On every plan they can customize the thank-you and order-status pages.

What to look for

• Plus requirement: in-checkout changes need Shopify Plus; thank-you pages don't
• Fields vs offers: form fields and rules, or revenue-driving upsells
• Post-checkout: thank-you and order-status blocks, next-order offers
• Pricing: flat vs per-order, and which plan unlocks checkout

The 6 best best custom checkout apps for shopify in 2026

1. UpsellPlus

Best for: All-in-one upsells across the whole funnel, Shopify Plus checkout. Rating: 5.0 (146) on the Shopify App Store.

UpsellPlus (that's us) runs one offer engine across 13 placements: product, home, collection and search pages, the cart page, cart drawer and cart popup, Shopify checkout, one-click post-purchase funnels, the Thank You and Order Status pages, and Shopify POS. It has Built for Shopify status.

• Offers chosen by hand, from collections or tags, or automatically by ShopBrain (similar, complementary, subscription upgrade, size upgrade, complete the set, clearance and more)
• Upsells to subscriptions with Shopify Subscriptions, Recharge, Appstle, Seal, Skio, Stay AI and other selling-plan apps
• 25 targeting rules, including Klaviyo segments, Shopify Markets, B2B and cart contents
• Multivariate A/B tests and holdout experiments that measure incremental revenue (on the $119 plans and up)
• Checkout customizations on Shopify Plus: styling, trust content, payment and delivery method visibility

Pricing: You can build and preview offers for free; going live needs a paid plan. Launch is $49/month (up to $500 in upsell revenue), Shopify Plus $119/month (up to $2,000, adds checkout upsells and A/B testing) and Scale $199/month (up to $5,000). No commission on sales; 14-day free trial on paid plans.

Watch out for: Checkout placements need Shopify Plus, as with every app that offers checkout upsells (a Shopify restriction).

2. Checkout Blocks

Best for: Free thank-you/order-status blocks; checkout fields on Plus. Rating: 4.1 (219) on the Shopify App Store.

Checkout Blocks is Shopify's own free app. On every plan it customizes the thank-you and order-status pages; on Shopify Plus it adds checkout fields, address rules, and payment/delivery method controls.

Pricing: Free.

Watch out for: Checkout customizations need Shopify Plus; upsells aren't its focus and the rating (4.1) is the lowest on this list.

3. Qikify Checkout Customizer

Best for: Checkout fields, discounts and validation rules with AI analysis. Rating: 4.9 (73) on the Shopify App Store.

Qikify Checkout Customizer adds branded checkout blocks, dynamic fields, checkout discounts, AI upsells, post-purchase and B2B extensions, and an AI analysis that scores your checkout.

Pricing: Free plan covers payment reorder/hide/rename, custom delivery methods, validation and (on Plus) branding. Checkout Premium is $99/month and adds custom fields, product offers, upsells and extra widgets. 14-day free trial.

Watch out for: Checkout upsells and custom fields are all on the $99 Premium plan.

4. Checkout Buddy

Best for: Checkout blocks, discounts and thank-you/account tools. Rating: 4.9 (27) on the Shopify App Store.

Checkout Buddy combines checkout upsells, discounts, thank-you page blocks and customer account tools. Plus stores get checkout fields, gifts and trust badges.

Pricing: Free for one customization. Thanks & Accounts $12, Discounts & Rules $12, Full Cart $20 and Buddy $67/month (Shopify Plus, adds checkout upsells, gifts and fields). 10-day free trial.

Watch out for: The checkout-upsell plan requires Shopify Plus at $67/month.

5. Checkout Plus

Best for: Checkout messages, trust badges, gifts and upsells. Rating: 5.0 (123) on the Shopify App Store.

Checkout Plus customizes checkout, thank-you and order-status pages with messages, trust badges, gift options, payment/shipping rules, surveys and checkout upsells.

Pricing: Free for dev stores. Basic $19 (thank-you/order-status + rules), Plus $49 (checkout customizations, Shopify Plus) and Advanced $99/month (checkout upsells and auto-add gifts). 7-day free trial.

Watch out for: Checkout customization needs the $49 Plus plan; checkout upsells the $99 Advanced plan.

6. Monk

Best for: Free gifts, BOGO and cart upsells with a rewards bar. Rating: 4.9 (600) on the Shopify App Store.

Monk combines free gift with purchase, BOGO and Buy X Get Y offers, cart upsells and a tiered progress bar, across product page, cart, checkout and post-checkout.

Pricing: A $1 first month (Black Friday offer), then $49/month for up to 1,000 monthly store orders and $149/month above that. 7-day free trial.

Watch out for: Priced by total store orders, not upsell revenue.

How to choose

• Checkout upsells + customizations in one app: UpsellPlus (from $119/month on Plus).
• Free, from Shopify: Checkout Blocks.
• Cheap fields, badges and messages: Checkout Buddy or Checkout Plus.
• Checkout validation and AI analysis: Qikify Checkout Customizer.

Frequently asked questions

Do I need Shopify Plus to customize checkout?

Yes for the checkout itself. Shopify only lets apps modify checkout on Plus. Every plan can customize the thank-you and order-status pages.

What is the best custom checkout app for Shopify?

For checkout upsells plus customizations, UpsellPlus (from $119/month on Plus). For free basics, Shopify's own Checkout Blocks. For fields and badges at a lower price, Checkout Buddy or Checkout Plus.

Can I add custom fields to Shopify checkout?

On Shopify Plus, yes — apps like Checkout Blocks, Qikify Checkout Customizer, Checkout Buddy and UpsellPlus add fields such as delivery notes or terms agreements.

Can I add upsells inside Shopify checkout?

On Shopify Plus, apps like UpsellPlus, Checkout Buddy, Checkout Plus, Qikify and Monk list in-checkout upsells or offers.

Try UpsellPlus

Build your offers in UpsellPlus for free, then go live with a 14-day free trial on any paid plan. Start for free or book a demo.

Related: Qikify Checkout Customizer alternatives, the 10 best upsell apps for Shopify, UpsellPlus checkout customizations.