POST to the addresses endpoint with a JSON body containing the address fields ('name', 'street1', 'street2', 'city', 'state', 'zip', 'country', 'phone'); include 'verify: ["delivery"]' in the payload to request verification at creation time.
Inspect the 'verifications.delivery' object on the returned address; check 'success' (boolean) and review any 'errors' array for specific field-level issues.
If 'success' is false, surface the error messages to the user or fall back to a manual address correction flow before proceeding.
Use the verified address 'id' directly in subsequent Shipment creation calls rather than re-submitting raw address fields; this avoids redundant verification and ensures the corrected address is used.
For US addresses, EasyPost may return a standardized ZIP+4 in the verified address object; store this for more precise carrier zone lookups.
Known gotchas
Address verification is a best-effort service; 'success: true' means the address is deliverable according to the verification provider's data, but does not guarantee the carrier will complete delivery.
International address verification has lower accuracy than US USPS-based verification; treat non-US results as advisory rather than authoritative.
Verification calls count toward your EasyPost usage; avoid verifying the same address repeatedly by caching verified address IDs tied to your customer records.
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