Shopify address validation API

Checkout checks, address autofill, and carrier checks are not one Address Validation API

Direct answer. Shopify Help Center documents address autocompletion and shipping-address validation at checkout, and a separate check against the shipping carrier’s database when you enter a shipping address for a shipping label. shopify.dev documents the Cart and Checkout Validation Function API, which can target delivery-address and billing-address fields, and the checkout targets purchase.address-autocomplete.suggest and purchase.address-autocomplete.format-suggestion. Nearby developer names on shopify.dev include Addresses API and DeliveryAddressValidationStrategy; treat each as that doc’s name. Confirm the live pages on shopify.dev and Shopify Help Center. This page does not name subscriptions.

PO Box Blocker — AddressFence (Shopify App Store · Write a review). Free blocks PO Boxes and parcel lockers on the shipping address at checkout, plus a small set of ZIP rules. Street-number checks and billing-address rules are on a paid plan. It is not Shopify’s address autocomplete, not the shipping-address validation setting, and not a carrier’s label check. This page names the surfaces merchants can configure — not the country-by-country checkout list.

Related: B2B PO Guard — Require PO — B2B purchase order number required at company checkout.

Free check first: PO box and street number address checker runs in your browser and sends nothing. Paste addresses and see which look like a PO box or lack a street number.

Checklist: which address check you mean

• Suggestions while the customer types, or a shipping-address check before the order: checkout settings. The country lists and toggles are on Shopify address validation at checkout.
• A custom suggestion provider: checkout address-autocomplete targets on shopify.dev, where the store can select an installed app. Help Center says that option is not shown the same way on every store.
• A shipping PO box block: Checkout Blocks address format validation, available to all merchants since 17 June 2026. A billing PO box or a street-number rule: a Cart and Checkout Validation Function or an app that provides one, not the autocomplete toggle.
• A label that the carrier will accept: the carrier check described under Shopify Shipping, after checkout.
• Do not search Admin for a product named Address Validation API until a Help Center or shopify.dev page uses that name for the setting you want.

Checkout validation and address autofill

Address collection preferences describes how shipping and billing addresses are collected and validated during checkout, including address autocompletion and validating shipping addresses before the order is placed. Suggestions come from services such as Google Autocomplete, not from the customer’s browser. Turning those settings on, which countries they cover, and how they differ from a PO-box rule is Shopify address validation at checkout. This page does not repeat that country list.

For a custom autocomplete provider, shopify.dev documents the checkout targets purchase.address-autocomplete.suggest and purchase.address-autocomplete.format-suggestion in Build customized address autocomplete. Help Center says stores that can install a third-party address-autocompletion app select it in the checkout editor. Which stores see that choice is on the Help Center page. This guide does not restate plan names.

A validation rule that blocks checkout can be native Checkout Blocks address format validation for a shipping PO box, or the Cart and Checkout Validation Function API for billing and other field errors. The Functions reference includes delivery-address and billing-address fields as error targets. That is a Functions API. It is not documented on that page as a product named Address Validation API. Whether a PO box can be entered at checkout at all is Does Shopify ship to PO Boxes?.

shopify.dev also documents an Addresses API for checkout UI extensions, and a Storefront API enum DeliveryAddressValidationStrategy with values for country-code-only and stricter cart address checks. Those names are easy to shorten to “address validation API”. They are developer references for checkout and cart operations. Confirm the page before you treat either name as an Admin product.

Carrier and partner checks are a later step

Reviewing address formats says that when you enter a shipping address for a shipping label, the address is checked against the shipping carrier’s database, and that carriers differ on format. The same article points merchants to carrier address checkers, including USPS, Canada Post, DHL, DPD, and Colissimo. That check is about buying a label. It is not the checkout autocomplete setting and it is not a Functions validation. Admin warnings on an order address, after checkout, are Validating addresses in your Shopify admin.

What this page is not

• Not legal advice, and not a statement that an address exists or is deliverable.
• Not a product page for something named Address Validation API. No Help Center page cited here uses that as the setting name.
• Not the checkout country list. That URL is Shopify address validation at checkout.
• Not a plan comparison. Options that depend on the store are left to Help Center.

Related pages

• PO box and street number address checker
• Shopify address validation at checkout
• Does Shopify ship to PO Boxes?
• Shopify Changelog: Checkout Blocks address format validation
• Shopify Help Center: address format validation
• Shopify Help Center: address collection preferences
• Shopify Help Center: reviewing address formats
• shopify.dev: Cart and Checkout Validation Function API
• PO Box Blocker — AddressFence — live App Store listing
• Shopify apps hub
• Tools

General information, not legal advice. Confirm the live Shopify Help Center and shopify.dev pages before you treat a checkout setting, a Functions API, or a carrier label check as one product. The app adds checkout validation rules. It does not replace autocomplete or the carrier’s address database.