Checkout / New features & Apps

Catch malformed shipping addresses
and block them proactively at checkout

Checkout Blocks' "Address format validation" is now available to all merchants. It blocks non-compliant shipping addresses at checkout, shows the buyer an inline error, and prevents them from completing the purchase until the address is fixed.

On this page
  1. What actually changes (understand it in 30 seconds)
  2. How it works: the flow from address entry to block
  3. Where to configure it (admin path)
  4. Address Blocker deprecation schedule
  5. What the article does and doesn't cover
  6. 3 steps to verify during migration
  7. 5 points developers should know
  8. 3 use cases you can apply to your business
  9. A one-line summary for your pitch

1What actually changes

Checkout Blocks' "Address format validation" is now available to all merchants.
As a new checkout rule, you canblock shipping addresses that don't comply with the format at checkout.
!

Before: they passed straight through

Even poorly formatted shipping addresses completed the purchase, and address issues often surfaced later in fulfillment and shipping.

Now: caught at entry

Addresses that don't meet the rules show the buyer an inline error, and checkout can't be completed until they're fixed.

2How it works: the flow from address entry to block

Buyer Enters shipping address Checkout online / agentic Same behavior for both Receives the address Address format Validation rules Determine compliant / non-compliant Compliant → purchase can complete Proceed to order as-is Non-compliant → blocked Show an inline error Cannot complete until fixed
The rules are applied consistently across both online and agentic (agent-driven) checkout experiences. Buyers see an inline error and cannot complete checkout until they correct the address.

3Where to configure it (admin path)

Settings Checkout Checkout rules Address format validation

In the Shopify admin Settings → Checkout → Checkout rules → Address format validation you can configure it from here.

4Address Blocker deprecation schedule

ItemDetails
Target Checkout Blocks' Address Blocker
Status Deprecated Currently scheduled for removal
Sunset (end of availability) August 31, 2026
Migration of settings If you currently use Address Blocker,compatible settings will automatically migrate to Address format validation over the coming weeks
Merchant action Not required No specific action is needed thanks to the automatic migration (as stated in the article)
Only "compatible settings" are migrated automatically.What happens if there are incompatible settings is not stated in the article. If you have built out custom logic in Address Blocker, it's safer to verify after migration that the new rules work as intended.

5What the article does and doesn't say

Stated

Confirmed facts

Rolling out to all merchants
New checkout rules block non-compliant shipping addresses
Settings path (Settings → Checkout → Checkout rules → Address format validation)
Applied consistently across both online and agentic
Buyers can't complete checkout due to inline errors
Address Blocker is deprecated, sunsetting 2026/8/31
Compatible settings auto-migrate within a few weeks, no action needed

Not stated

Not described in the article (do not infer)

Specific criteria for "format compliance" and supported countries/regions
Eligible plans and required permissions
Whether it applies to billing addresses
Relationship with Admin API / Webhook / Checkout UI Extensions
Handling of incompatible settings that aren't auto-migrated
See the Help Center for details (article link).

63 steps to verify your migration

1

Take stock of your current usage

Check whether you're using Address Blocker and what blocking settings you have configured.

2

Find where the new rules live

Open Settings → Checkout → Checkout rules → Address format validation.

3

Verify the actual behavior after migration

After auto-migration, place a test order to confirm inline errors appear as intended. Complete this by 8/31.

The article says "no action needed, auto-migration," buta clear sunset date (2026/8/31) is set,so it's safer to confirm there are no missed migrations or overlooked incompatible settings before the deadline.

75 points engineers should know

1. It's really a "checkout rule"

The feature isn't a permanent app, but is offered as one of the Checkout rules. The key point is that it applies consistently across both online and agentic checkout.

inline

2. The block is a "hard block"

Non-compliant addresses trigger an inline error, and checkout can't be completed until they're fixed. It stops the purchase rather than just passing through a warning.

8/31 sunset

3. Address Blocker has a scheduled retirement

Already deprecated and sunsetting on 2026/8/31. Compatible settings auto-migrate within a few weeks with no action needed, but you still need to manage the deadline.

web AI

4. It also works for agentic checkout

The same rules apply to purchase flows via agents. Concerns about address quality dropping on AI-driven orders can be covered uniformly at the rule level.

spec ?

5. Validation criteria and API specs aren't documented in the article

The specific logic for determining "format compliance," supported countries/regions, and the relationship with Admin API, Webhook, and Checkout UI Extensions are not described in the article.When combining with automation or custom validation, validate in advance using the Help Center and a sandbox.

83 use cases you can apply to your business

! Needs fixing
USE CASE 1

Reducing shipping issues and redelivery costs

Challenge
Orders go through with incomplete digits or malformed addresses, leading to "undeliverable," "redelivery," and "address correction inquiries" after shipment, which become a cost.
Solution
Enable Address format validation to block non-compliant shipping addresses at checkout.
Impact
By having customers correct addresses at input time, you reduce address-related problems after shipping along with the associated CS and logistics costs.
Technical notes
Buyers see an inline error and can't complete the order until they fix it. The rule is applied consistently across both online and agentic checkout.
Blocker Deadline 2026/8/31
USE CASE 2

Managing a planned migration away from Address Blocker

Challenge
An existing store uses Address Blocker, and there's concern about migration gaps before the 2026/8/31 sunset.
Approach
Rely on automatic migration, then set up an operation that places test orders against the new rule (Address format validation) after migration to verify the block works as intended.
Impact
Prevents a "validation silently turned off without anyone noticing" situation on the sunset day, keeping address validation uninterrupted.
Technical notes
Automatic migration only covers "compatible settings." How incompatible settings are handled isn't described in the article, so always include a post-migration diff check.
AI
USE CASE 3

Uniformly ensuring address quality for agentic (AI agent–driven) orders

Challenge
As agent-driven purchase flows grow, ensuring the shipping address quality of orders that aren't entered by hand becomes a challenge.
Approach
Enable the address format validation rule. Take advantage of the fact that the same rule used for online is consistently applied to agentic checkout as well.
Impact
Without implementing it separately per flow, you can block malformed addresses by the same standard even for agent-driven orders.
Technical notes
The criteria, scope, and API specifications aren't described in the body. If you build the agent integration yourself, check the behavior in the Help Center.

9One-line summary you can use in a proposal

"A new Checkout rule Address format validation blocks non-compliant shipping addresses at the moment they're entered.
Applied consistently across both online and agentic, with an inline error preventing completion until fixed.
The old Address Blocker sunsets on 2026/8/31, and compatible settings migrate automatically (no work required—though a post-migration check is recommended)."