// Glossary
CAN-SPAM
The US law setting rules for commercial email: honest headers, a valid address, and a working unsubscribe.
Definition
CAN-SPAM is the US federal law governing commercial email. It requires accurate From and subject lines, a valid physical postal address, clear identification of the message as an ad where applicable, and a functioning opt-out that's honored promptly. It requires no prior opt-in for commercial email (including B2B) but does mandate easy unsubscribe and truthful routing. Violations can draw per-email penalties, so cold email programs must comply.