LetterAgent
Mail physical letters by just asking your AI assistant.
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No customs form is needed if the envelope contains only documents: letters, contracts, photos, and paperwork cross borders as correspondence, not merchandise. The moment anything inside counts as goods, like a USB drive, a sample, or a gift, the letter becomes a small packet that must be declared.
Documents are written or printed matter with no commercial value as objects: letters, invoices, contracts, certificates, manuscripts, photographs, blueprints. Customs treats these as correspondence, and correspondence moves through the international mail stream without a declaration form. This is the everyday case for cross-border letters, and it is why mailing a letter abroad is so much simpler than shipping a parcel.
The line gets interesting at the edges. A printed book is usually still fine as a document or printed matter. But anything with a value as a thing, not as information, is goods: a USB stick with the contract on it, a product sample, a key, a coin, a SIM card. The medium is the problem, not the message. If the recipient could use or sell the object inside, declare it.
The envelope stops being a letter in customs terms and becomes a small packet. That means a declaration form (the small green CN22 label for low-value goods, or the longer CN23 for heavier or higher-value items), a stated value, a description of the contents, and the sender's and recipient's details. Many countries now also expect the electronic advance data to match, which the post office captures when you fill out the form at the counter or online. Skip the declaration and the packet can be held, returned, or seized: customs officers are not guessing what is inside an undeclared lump in an envelope.
| Inside the envelope | Customs treatment | What you do |
|---|---|---|
| Letters, contracts, photos, certificates | Documents: no declaration | Address it, stamp it, mail it |
| USB drive, sample, gift, merchandise | Goods: must be declared | Fill out the customs form at the post office |
| Cash or cash-like items | Goods and often prohibited | Do not mail cash internationally; many countries ban it outright |
| Mixture of documents and goods | The goods rule wins | Declare the goods; list the documents as part of the shipment |
Two reasons. First, some postal clerks default to asking about contents on every international item, and "documents only" is a perfectly good answer that ends the conversation. Second, certain countries or carriers apply declaration requirements to everything as a local rule, especially for tracked or registered international items. When in doubt, the five seconds of the clerk's question beats a held-up letter.
If it contains only documents, no: registration is about proof of delivery, not about contents. But this is the case where a clerk is most likely to ask what is inside, because registered items get more scrutiny. "Documents only" is still the right answer, and the letter moves through.
LetterAgent mails printed letters only: your text, printed single-sided on 8.5x11 paper, in a double-window envelope, with no inserts or objects of any kind. That means a LetterAgent letter to a US or Canadian address is always documents-only by construction, and the documents rule above applies. (LetterAgent currently mails to US and Canadian recipients; the customs question matters when you mail a letter yourself across other borders.)
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is printed and mailed.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
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