BRC-20, or Bitcoin Request for Comment 20, is modeled after the Ethereum protocol called ERC-20 (Ethereum Request for Comment 20) and was introduced in March 2023 by Domo. BRC-20 tokens employ JSON inscriptions to deploy tokens, mint tokens, and move tokens around. $Ordi is the first token deployed as a BRC-20, while $Sats is responsible for 21 million inscriptions.