Zest automatically validates shipping addresses so you can catch delivery problems before they become costly reshipments. Every address — whether entered manually or uploaded via CSV — goes through validation checks that flag issues in real time.
You control your own shipping rules: which states you ship to, whether PO boxes are allowed, and how errors are surfaced to your recipients. No engineering required.
Before you start, you'll need:
Brand admin access in Zest.
Your shipping profile configured with the countries and states you ship to.
Overview: How Address Validation Works
When a recipient enters or uploads an address, Zest checks it using the Google Maps API. In self-service Storefronts, validation runs synchronously — the recipient sees feedback as they enter their address.
Zest checks for:
Invalid or mismatched ZIP codes.
PO boxes (when you've enabled blocking).
Addresses in states or countries outside your shipping profile.
Incomplete or undeliverable addresses.
Suggested corrections (e.g., a misspelled street name or incorrect ZIP code).
Validation Levels: Errors vs. Warnings
Zest uses two levels of feedback to draw attention to addresses that need attention before sending. Here's what they are and what they mean.
Errors (hard stops)
Errors prevent an order from moving forward until they're resolved.
Examples include:
An address in a state or country outside your shipping profile.
A PO box address when your settings block PO box delivery.
A completely invalid or unrecognizable address.
Errors are shown in red in your dashboard. Only brand admins can bypass errors — your customers or collaborators cannot.
Warnings (soft flags)
Warnings are suggestions that can be dismissed if the sender confirms the address is correct.
Examples include:
A suggested address correction (e.g., a corrected ZIP code or street spelling).
An address that can't be fully verified but isn't definitively wrong.
A missing apartment or suite number on a business address.
Warnings are shown in orange in your dashboard. Customers with collaborator access can dismiss warnings after reviewing them.
Note: When a customer dismisses a warning, Zest records that action. If a package doesn't arrive because of an address the customer approved, you can reference that history in your customer service conversations.
Configuring PO Box and Address Type Restrictions
Blocking PO box deliveries
To block shipping to PO boxes:
Go to Settings in your Zest dashboard.
Select Shipping.
Under Shipping to PO boxes, select Block shipping to PO boxes.
Click Save.
When this setting is enabled, any address containing "PO Box" will be flagged as an error during address entry or CSV upload. Recipients will see a message stating that your brand doesn't ship to PO boxes and will be prompted to provide an alternative delivery address or remove themselves from the order.
Tip: The PO box blocker looks for the text "PO Box" in an address field. It does not automatically catch military addresses using APO, FPO, or DPO formats, which use a different address structure. See Troubleshooting Common Validation Issues for guidance on handling military addresses.
The PO box restriction is an all-or-nothing setting — you cannot block PO boxes in some regions while allowing them in others. In Concierge, admins can manually bypass the restriction for individual addresses as needed.
Residential vs. commercial address detection
If your brand needs commercial address detection — for example, if your carrier charges different rates for business vs. residential delivery — contact your Zest account manager to enable this feature.
Important: Zest's residential/commercial classification is used within Zest for display and flagging purposes. This designation is not currently passed to connected ecommerce platforms (such as Shopify) or downstream fulfillment systems. Brands whose warehouses or carriers need this distinction for carrier routing should handle the classification separately.
Setting Up State and Regional Shipping Restrictions
You can configure exactly which states and countries you ship to using your shipping profile in Zest. Once configured, Zest automatically blocks orders to addresses outside your allowed regions — no manual filtering required.
Common use cases include:
Wine and alcohol brands restricting shipments to states with alcohol delivery laws (e.g., Utah).
Brands shipping only to the contiguous 48 US states (excluding Hawaii and Alaska).
Brands with US-only fulfillment that want to block international orders.
When a recipient's address falls in a restricted state or country, Zest flags it with a message like: "Sorry, shipping to this state is not available." The recipient must either provide an alternative address or be removed from the order.
To update your shipping regions, navigate to your Shipping Profile settings or contact your Zest account manager.
Best Practices for Bulk CSV Uploads
Uploading large recipient lists is the fastest way to add many recipients at once. Here are best practices to keep validation running smoothly.
Before uploading:
Use Zest's CSV template to ensure column headers match expected field names.
Verify addresses against Google Maps before uploading if accuracy is critical.
Review your shipping profile to confirm you're shipping to all the countries and states in your list.
During upload:
Validation runs automatically after upload. For smaller lists, this is nearly instant. For lists with 150+ recipients, allow a few extra minutes for validation to complete.
Your dashboard will show validation progress and flag any issues.
For large uploads (300+ recipients):
Consider splitting the list into smaller batches for faster feedback.
If validation appears to stall, take a screenshot and contact Zest support — the system processes slowly on very large batches but should not freeze.
For time-sensitive orders, smaller batches give you faster turnaround on errors.
Handling validation failures:
Remove addresses with hard errors from your upload file and place them in a separate follow-up file.
Correct the errors in the follow-up file and re-upload once confirmed.
Address suggestions:
Zest may suggest a corrected version of an address (for example, a standardized ZIP code or street name). These suggestions come from Google Maps and are generally accurate — but evaluate them case by case.
City names can vary for the same ZIP code. For example, "Salt Lake City" and "Murray" may both be valid for overlapping areas. When in doubt, have the gifter verify the address directly.
Special characters in recipient names:
A small number of recipients use special characters in name fields (e.g., accent marks, hyphens). These are generally supported but may occasionally cause issues with print fulfillment partners. Check with your fulfillment vendor about which characters they support.
International Address Validation
Zest supports address validation for many international destinations using the Google Maps API.
Well-supported regions:
United States and Canada — fully validated, including ZIP/postal code verification and USPS CASS deliverability data for US addresses.
UK, France, Australia, and many other countries — validated via Google Maps API with good coverage.
Regions with limited validation:
For certain regions, full address validation is not available. When validation isn't supported, Zest will accept the address with a warning rather than blocking it. These regions include:
US Virgin Islands
Cayman Islands
Guyana
Hong Kong
Morocco
Nepal
Tips for international orders:
Double-check all international addresses against Google Maps before submitting, especially for countries with complex address formats.
If validation issues persist, contact Zest support — admins can process problematic addresses through Concierge where individual bypasses are available.
Note: Some international addresses, particularly those with complex multi-line formats (such as university campuses or large office complexes), may not validate cleanly. If you encounter this, Zest support can help on a case-by-case basis.
Zest uses Google Maps API for validation, not USPS validation. Some carriers (particularly UPS) validate against USPS data, which can occasionally create discrepancies — a Google-validated address may be flagged by USPS-based carrier systems. If you notice this pattern, cross-reference flagged addresses against multiple sources before shipping.
Troubleshooting Common Validation Issues
My recipient's address was flagged, but the address looks correct.
Zest may flag an address as a warning even when it is deliverable. This can happen with:
New developments or recently renamed streets not yet in Google Maps data.
Addresses in regions with lower Google Maps coverage.
ZIP codes that are valid but associated with multiple city names.
If you're confident the address is correct, you can dismiss the warning in Concierge. The order will proceed with the confirmed address.
Address autocomplete isn't working.
Address autocomplete requires a live connection to the Google Maps API. If autocomplete stops working, the issue is typically with the Google Maps service itself, not your Zest account. Recipients can still type their full address manually. The issue usually resolves on its own. If it persists, contact Zest support.
Military addresses (APO/FPO/DPO) aren't being caught by my PO box block.
The PO box blocking feature detects the text "PO Box" in an address. Military addresses use APO (Army Post Office), FPO (Fleet Post Office), and DPO (Diplomatic Post Office) designations and do not use the "PO Box" format — so they won't be caught by the PO box block automatically.
If your brand needs to restrict military address shipments:
Test a known military address in your setup to confirm whether it goes through.
If it does and you need to block it, contact Zest support to explore a custom solution.
Browser autofill is overwriting address fields.
Zest has addressed a past issue where browser autofill could overwrite address data after a spreadsheet upload. Address fields are now locked after upload to prevent this. If you encounter this problem, try disabling browser autofill for the Zest portal or contact Zest support.
ZIP+4 codes — are they required?
No. The standard 5-digit ZIP code is sufficient for address validation and order processing. If you see a validation warning about a postal code, it usually indicates an incorrect ZIP code rather than a missing +4 extension. Verify against Google Maps when in doubt.