Ordinals (Bitcoin inscriptions)

The Ordinals protocol, launched by developer Casey Rodarmor in January 2023, gives every satoshi a serial number based on the order in which it was mined and tracks it through transactions. An inscription attaches content, such as an image, text or code, to a specific satoshi by storing it in the witness data of a Taproot transaction, so the content lives entirely on the Bitcoin blockchain.

Inscriptions created a market for Bitcoin-native collectibles and led to token experiments such as BRC-20. Wallets and marketplaces had to add special handling so that users would not accidentally spend inscribed satoshis as fees. Waves of inscription activity have at times pushed Bitcoin fees sharply higher.

Bitcoin nodes do not recognise inscriptions; they exist only through indexing software that follows the Ordinals rules, so an unaware wallet treats an inscribed satoshi like any other. The use of block space for images remains disputed among Bitcoin users.