Toll-Free Number
A toll-free number is a phone number where the called party (not the caller) pays for the call. In the US, toll-free uses NPAs 800, 833, 844, 855, 866, 877, 888 (and the legacy 880-887). Most other countries have their own toll-free range: UK 0800/0808, Germany 0800, France 0805, etc.
US toll-free administration (RespOrg / SOMOS)
Unlike geographic numbers, US toll-free numbers are administered by SOMOS (the centralized toll-free database). The carrier holding the number is called its RespOrg. Porting a toll-free number is a RespOrg change in SOMOS, not a normal LNP order — see porting tutorial.
Vanity numbers
Vanity numbers are toll-free numbers that spell a memorable word: 1-800-FLOWERS, 1-888-NEW-CARS, etc. They are valuable brand assets and the secondary market trades them for $100-$1M+.
STIR/SHAKEN considerations
US toll-free traffic must be signed STIR/SHAKEN A-attestation by the originating carrier. Inbound toll-free is unaffected (the caller's carrier handles signing).
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