Starting October 19, 2026, the US Postal Service can send a merchant a bill, directly or through a third-party representative, when foreign customs charges on a shipment go unpaid. Practical Ecommerce’s coverage of the change lays out a rule that sounds narrow on paper. However, it lands at a genuinely bad time for anyone shipping internationally. It arrives right as the underlying customs landscape has shifted underneath every seller doing cross-border business.
USPS Billing Policy and Customs Enforcement Mechanics
The policy itself is straightforward: USPS will bill merchants when certain foreign customs fees on a shipment remain unpaid. That liability doesn’t disappear if the package is delivered, lost, damaged, or returned. The shipper remains responsible. The article is careful to add that this does not mean every US merchant will receive a bill, because responsibility for customs charges depends on the destination country’s requirements and the shipping method. Merchants are required to pay the invoice even while actively disputing an assessment they believe is wrong. Furthermore, any past-due invoice accrues interest at 6% annually until it’s settled. A disputed, possibly incorrect charge still has to be paid on time, with the dispute running in parallel rather than pausing the bill. USPS does not check whether the foreign entity calculated the charge correctly, so the dispute has to be taken up with whoever assessed it.
This isn’t unique to USPS. The article notes that all carriers, UPS and FedEx included, now have to ensure these charges actually get paid. This suggests the policy is less a USPS-specific quirk and more a response to a broader shift in how customs enforcement works across the entire international shipping chain.
Global De Minimis Exemptions and Carrier Enforcement Drivers
The immediate cause sits in Europe. On July 1, 2026, the European Union eliminated its de minimis exemption, the threshold under which low-value shipments crossed the border duty-free. Low-value international orders into the EU that used to clear customs without any duty assessment now face one. The EU introduced a temporary flat charge of €3.00 (about $3.36) per Harmonized System Code product classification to handle the transition, a rate the article indicates is set to run through June 30, 2028. As a result, low-value packages that used to cross into the EU duty-free often aren’t anymore.
That combination of more shipments now owing duties than before and carriers now formally on the hook to ensure those duties get collected is what prompted USPS to act, according to the article. A merchant used to de minimis-era shipping, where most parcels crossed borders without a customs bill ever entering the picture, is now operating in an environment where that is no longer the default assumption. In this new reality, an unpaid bill doesn’t just sit as an abstract liability; it accrues interest.
Harmonized System Codes, Importer of Record, and Platform Configurations
Two concepts sit underneath almost everything in this change. The Harmonized System Code is the standardized, typically six-digit classification customs authorities use worldwide to decide which duty rate applies to a given product. Without an accurate code attached to a shipment, there is no reliable way to calculate what should be owed or whether it has been paid correctly. The Importer of Record is whichever party, buyer or seller, is responsible for paying the duty. This is determined by the shipping terms (Incoterms) agreed upon for the order: under Delivered Duty Paid terms, the seller pays; under Delivered At Place terms, the buyer does. A seller who hasn’t deliberately chosen which of those applies to their international orders leaves that determination to chance, right as the financial stakes of getting it wrong have increased.
For a store running on PrestaShop or OpenCart, whether you can store an HS classification on each product depends on your version, theme, and any shipping or customs extensions, so check what your admin panel and installed modules actually support before assuming the data is already there. Either way, this is mostly a data and configuration problem rather than something that requires a platform migration to fix. The real work is auditing whether that data is populated and accurate for every product shipping internationally, not whether the capability technically exists in the admin panel.
USPS Delivered Duty Paid Service and Prepayment Solutions
The most direct mitigation the article points to is USPS’s own Delivered Duty Paid (DDP) service, which prepays duties, taxes, and fees when postage is bought rather than leaving them to be billed after the fact. The article says it works for shipments to 18 countries, including Canada and the United Kingdom. USPS’s DDP page currently lists Austria, Belgium, Canada, Denmark, Estonia, Finland, France, Germany, Italy, Luxembourg, Malta, Monaco, the Netherlands, Portugal, Slovakia, Spain, Sweden, and the United Kingdom, and says more countries are expected to be added. It works with Priority Mail Express International, Priority Mail International, and First-Class Package International Service. USPS does not charge for DDP, but its third-party provider (Zonos, per the article) includes a fee in the quote.
For destinations outside that eligible list, the article’s advice is to treat duties and taxes as part of the sale rather than the customer’s problem, which means estimating them at the point of sale with your shipping software. This solves two problems at once: it reduces the odds of an unpaid-duty bill showing up weeks later, and it lets the actual landed cost be disclosed to the buyer before checkout rather than as a surprise fee on delivery, which is exactly the kind of thing that depresses conversion rates.
Beyond carrier-level tools, the practical audit for any store shipping internationally right now covers three things: confirm every internationally shipped product has an accurate HS code attached, not a placeholder or a generic catch-all; decide explicitly which Incoterms apply to international orders rather than defaulting to whatever the shipping plugin happened to select; and calculate total landed cost (product, shipping, insurance, and the duty itself) before setting international pricing, rather than discovering the gap after a customs bill with 6% annual interest arrives.
Customer Communication and Financial Impact of International Compliance
Transparent communication with the buyer protects profit margins just as much as compliance does. An international shipping policy that states plainly how duties and taxes get collected, and whether the buyer should expect to pay anything additional on delivery, prevents unexpected disputes. Surprise costs at delivery are one of the most reliable ways to turn an otherwise satisfied international customer into someone leaving a one-star review over a fee the seller, not the carrier, ultimately chose not to disclose upfront. Getting ahead of the HS code and Incoterms decisions now is cheaper than untangling an unpaid-duty invoice with interest accruing on it later.