Who writes and reviews these guides

What we verify

Address formats are checked against USPS Publication 28 for the United States and against national postal guidance for other countries. Postal-code examples are checked against the maintained fixture set that powers the generator. Where a claim depends on a state tax authority or a provider policy, the page links to that source.

A format check is not a delivery check. We say so on the tool pages because a syntactically valid address can still be undeliverable.

How AI is used

Drafts and translations may use AI assistance. A published page is not accepted just because a model produced it: the field order, postal pattern, worked example and tool output are checked separately. When a page is only translated at the interface level, the English content remains canonical and the localized copy is marked accordingly.

Corrections

If a format, postal rule or provider statement is wrong, email support@addresstool.org with the page URL and the source that should be used. Corrections are applied to the page and the updated date is changed.

What this site does not do

• We do not sell or claim to verify real identities.
• We do not provide documents, bills, or proof-of-address files.
• We do not promise that a synthetic address is mailable.
• We do not publish a provider comparison as an endorsement; links and limits can change.