How Tokens on Bitcoin Work and Why They Are Controversial On the weekend of May 6, 2023 the Bitcoin blockchain ground to a temporary halt, when the number of unconfirmed transactions hit a record high. Fees were spiking, and leading crypto exchange Binance had to pause withdrawals — twice. How did that happen? The BRC-20 protocol. BRC-20 Explained 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 an anonymous developer known as Domo. BRC-20s are basically (with some major caveats like a lack of smart contracts) Bitcoin’s version of ERC-20s.