# What does a Checkout Extensibility migration actually cost for a mid-market Shopify Plus store with 5-10 custom checkout integrations?

Reviewed by Martin Dejnicki, Director of SEO & AI Search · facts verified October 11, 2026 · canonical: https://deploi.ca/shopify/faq/checkout-extensibility-migration-cost-5-10-integrations

## Short answer

No published price exists for a Checkout Extensibility migration of 5 to 10 integrations, because cost follows each integration, not the store. Shopify's Partner Directory lists 2,271 checkout upgrade partners, and 14 of the 16 on its first page show "Contact for pricing" ([Shopify Partner Directory](https://www.shopify.com/partners/directory/services/store-setup/checkout-upgrade), October 2026). So price each integration's replacement, then the program around it.

- **Published market price:** None for a 5 to 10 integration migration. Shopify's Partner Directory lists 2,271 checkout upgrade partners; on page one, 14 of 16 show Contact for pricing and two show starting prices of $500 and $1,000 (October 2026) ([Shopify Partner Directory, Checkout upgrade](https://www.shopify.com/partners/directory/services/store-setup/checkout-upgrade))
- **Record estimate, program length:** 8 to 14 weeks end to end. The checkout extensibility record's illustrative estimate for a real Scripts footprint; it adds that one margin-critical Function can ship in 2 to 3 weeks (Deploi decision record, October 2026) ([Deploi Build vs. Buy, Build or Buy Your Checkout Extensibility Upgrade on Shopify Plus?](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program))
- **Record estimate, upkeep:** About 15 to 20% of build cost a year. After cutover: API version updates, extension changes and a pixel re-check at each checkout upgrade; the checkout extensibility record's illustrative estimate (October 2026) ([Deploi Build vs. Buy, Build or Buy Your Checkout Extensibility Upgrade on Shopify Plus?](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program))
- **Record estimate, app path:** About $14,900 to $39,000 over three years. Renting parity apps for the generic rules: $500 to $3,000 to set up, then $14,400 to $36,000; the checkout extensibility record's illustrative estimate, not a quote (October 2026) ([Deploi Build vs. Buy, Build or Buy Your Checkout Extensibility Upgrade on Shopify Plus?](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program))

## Deploi's call

No honest per-store price exists, so price a Checkout Extensibility migration per integration and refuse to quote the store. Any fixed quote issued before the parity map, the written list of every rule the old checkout ran, is a quote for a scope neither party has seen. It will be renegotiated in week four.

**BUILD: Commission the full program when**

- Two or more integrations have no like-for-like Shopify Function, the code Shopify runs at checkout, and no vendor extension.
- The rules touch margin. Deploi's checkout extensibility record scores real Scripts-era logic BUILD ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026).
- A written parity map exists, so agency quotes price the same scope.

**CUSTOMIZE: Rent apps for the generic rules when**

- An app's settings page expresses every rule you keep.
- The record's app path fits the budget: about $500 to $3,000 to set up and $14,400 to $36,000 over three years, illustrative ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026).
- You commission only the audit and a pixel check, the record's CUSTOMIZE path for a light Scripts footprint ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026).

## Why is there no published price for a 5 to 10 integration migration?

There is no published price because two Shopify Plus stores with the same integration count can need very different work. "Eight custom checkout integrations" can mean a shipping rule with a like-for-like Shopify Function, or a bespoke insurance widget behind a partner's application programming interface (API). The market shows it: Shopify's Partner Directory lists 2,271 checkout upgrade partners, and 14 of the 16 on its first page show "Contact for pricing" ([Shopify Partner Directory](https://www.shopify.com/partners/directory/services/store-setup/checkout-upgrade), October 2026). The other two show self-set starting prices of $500 and $1,000, which price a partner's entry service, not your checkout. [Which checkout surfaces each Shopify plan lost](https://deploi.ca/shopify/faq/checkout-liquid-shutdown-all-plans-or-plus-only) sets out what there is to replace.

## Is a Checkout Extensibility migration still ahead of a Plus store in October 2026?

No: on Shopify Plus the old checkout code has already stopped, so the work is a rebuild of what stopped rather than a migration ahead of a deadline. Shopify Scripts stopped on 30 June 2026 ([Shopify Help Center](https://help.shopify.com/en/manual/checkout-settings/script-editor/transitioning-to-functions), October 2026). Automatic upgrades reached the Thank you and Order status pages in January 2026 ([Shopify Help Center](https://help.shopify.com/en/manual/reports-and-analytics/google-analytics/google-tag-manager), October 2026). So each quote now prices restoring a rule or a tag, and the first job is listing what stopped. Every week spent scoping is a week the store trades without that rule, so scope fast and price per item.

## What does each type of checkout integration cost to replace?

Each integration's cost follows its replacement path, and two types carry most of the risk: discount logic with no like-for-like Shopify Function, the code Shopify runs at checkout, and third-party widgets that wait on a vendor. App blocks and pixels, the other two paths, are mostly configuration.

**Discount logic with no Function equivalent and partner widgets carry the risk; the rest run low to medium**

| Integration type | Replacement path | Relative cost |
| --- | --- | --- |
| Discount or shipping rule with a like-for-like Function | Custom Shopify Function | Low to medium |
| Discount logic with no one-to-one Function | Redesign the rule with merchandising, then build | High |
| Post-purchase upsell | App block on the Thank you page | Low, plus a subscription |
| Analytics and conversion tags | App pixel or custom pixel | Low to medium |
| Custom fields at checkout | Checkout user interface (UI) extension, Plus-only on the Information, Shipping and Payment steps | Medium |
| Partner widget with its own application programming interface (API) | The vendor's own extension, if one exists | Unbounded |

Sources: [Shopify developer docs, About Shopify Functions](https://shopify.dev/docs/apps/build/functions); [Shopify developer docs, Checkout UI extensions](https://shopify.dev/docs/api/checkout-ui-extensions/latest). Verified October 11, 2026.

Tags are cheap to move and costly to get wrong, so [budgeting for a tracking app](https://deploi.ca/shopify/faq/checkout-extensibility-tracking-app-upgrade-budget) is a separate decision.

## What does Deploi's decision record estimate for the full program?

Deploi's checkout extensibility record estimates 8 to 14 weeks for the full program, from audit to staged cutover, for a real Scripts footprint ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026). The record puts upkeep after cutover at about 15 to 20% of build cost a year, with no subscription line. The record also prices renting apps for the generic rules instead, so a store can see what the build has to beat.

**The full program takes 8 to 14 weeks plus yearly upkeep, while renting apps for generic rules runs about $14,900 to $39,000 over three years**

| Path | Time | Record estimate (illustrative) |
| --- | --- | --- |
| Build the full program | 8 to 14 weeks | Upkeep of 15 to 20% of build cost a year |
| Rent apps for the generic rules | Days | About $14,900 to $39,000 over three years, setup included |

Sources: [Deploi Build vs. Buy, Build or Buy Your Checkout Extensibility Upgrade on Shopify Plus?](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program). Verified October 11, 2026.

A Scripts port on its own is narrower: [the three-year build-versus-app arithmetic](https://deploi.ca/shopify/faq/custom-function-vs-discount-app-long-term-cost) runs on the Scripts-to-Functions record, and [what an agency-built discount Function costs](https://deploi.ca/shopify/faq/custom-discount-function-agency-build-cost) prices one rule.

## What moves the price most?

Undocumented rules move the price most, because someone has to work out what an old rule did before anyone can rebuild it. Deploi's decision records name four drivers, ranked here by Deploi's judgment:

1. **Rules with no owner.** The checkout extensibility record calls them orphan rules and says to "budget archaeology time before rewrite time" ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026).
1. **A parity test, a replay of old carts against the new code.** The Scripts-to-Functions record says skipping it "converts silent Script death into silent Function drift" ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/scripts-functions-migration), October 2026).
1. **App stacking.** The checkout extensibility record warns that app parity "adds two or three subscriptions that never stop billing", so price the stack, not the app ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026).
1. **Scope creep.** The checkout extensibility record says to "hold the parity map as the contract and push improvements to phase two" ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026); the parity map is the list of rules to restore.

[Why some migrations went smoothly and others did not](https://deploi.ca/shopify/faq/checkout-extensibility-migration-smooth-vs-painful) shows how the same drivers play out on the schedule.

## When is the honest cost zero?

The honest cost is zero when the audit finds nothing to rebuild, and Shopify already generates the first scoping document for free. The Shopify Scripts customizations report under Apps > Script Editor lists the Scripts that were active before 30 June 2026, and it exports as a comma-separated values (CSV) file ([Shopify Help Center](https://help.shopify.com/en/manual/checkout-settings/script-editor/transitioning-to-functions), October 2026). Deploi's checkout extensibility record says a Scripts-deprecation audit "takes a day", and one Deploi audit came back with zero exposure ([Deploi decision record](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), October 2026).

> **When not to commission a migration program**
> - **When the Scripts report is empty and no app on the store waits on an update.** There is nothing to rebuild, so there is nothing to price.
> - **When the integration is branding.** The checkout and accounts editor and the Checkout Branding API (application programming interface) handle it ([Shopify Help Center](https://help.shopify.com/en/manual/checkout-settings/customize-checkout-configurations/customization-options), October 2026).
> - **When a public app already does the job.** Stores on any plan can use public App Store apps that contain functions ([Shopify developer docs](https://shopify.dev/docs/apps/build/functions), October 2026), so a pre-built Function app may cover a common rule.

## Deploi's point of view

**Where we disagree.** The category prices this as a technical migration with a per-integration rate. A meaningful share of the effort is a merchandising conversation about which rules should survive at all, and that time belongs in the estimate rather than hidden in contingency.

**What we ask for first (our judgment, not a measurement).** The variance between two superficially identical Plus stores is almost entirely explained by how many checkout rules nobody can currently explain. That count, not the integration count, is the number worth asking for on the first call.

**What this page adds.** The parent dates which checkout surfaces each plan lost. This page prices the rebuild: why no per-store price exists, the replacement path and risk for each integration type, the decision records' timelines and app-path costs, and the drivers that move a quote.

## When this answer changes

- Shopify ships Function APIs that cover rules which today need a redesign, which moves those integrations down the cost table.
- Shopify retires the Script Editor app or its Scripts customizations report.
- Deploi's checkout extensibility or Scripts-to-Functions record changes its timeline, upkeep share or app-path figures.
- A checkout app category consolidates and a parity app this page counts on leaves the App Store.

## Sources

1. [Shopify Partner Directory, Checkout upgrade](https://www.shopify.com/partners/directory/services/store-setup/checkout-upgrade), checked October 11, 2026
2. [Shopify developer docs, About Shopify Functions](https://shopify.dev/docs/apps/build/functions), checked October 11, 2026
3. [Shopify developer docs, Checkout UI extensions](https://shopify.dev/docs/api/checkout-ui-extensions/latest), checked October 11, 2026
4. [Shopify Help Center, Transitioning from Shopify Scripts to Shopify Functions](https://help.shopify.com/en/manual/checkout-settings/script-editor/transitioning-to-functions), checked October 11, 2026
5. [Shopify Help Center, Google Tag Manager](https://help.shopify.com/en/manual/reports-and-analytics/google-analytics/google-tag-manager), checked October 11, 2026
6. [Shopify Help Center, Customization options for Thank you and Order status pages](https://help.shopify.com/en/manual/checkout-settings/customize-checkout-configurations/customization-options), checked October 11, 2026
7. [Deploi Build vs. Buy, Build or Buy Your Checkout Extensibility Upgrade on Shopify Plus?](https://deploi.ca/shopify/build-vs-buy/checkout-extensibility-adoption-upgrade-program), checked October 11, 2026, Deploi research
8. [Deploi Build vs. Buy, Should You Build or Buy Your Shopify Scripts-to-Functions Migration?](https://deploi.ca/shopify/build-vs-buy/scripts-functions-migration), checked October 11, 2026, Deploi research