Bitcoin Ordinals are the latest layer-2 solution enabling decentralized storage of digital art on the Bitcoin blockchain. Ordinals will now allow users to migrate their Ethereum ERC-721-based nonfungible tokens (NFTs) to the Bitcoin blockchain with the launch of the BRC-721E standard.
The BRC-721E standard was jointly launched by the Ordinals market — an Ordinals-based marketplace — and the Bitcoin Miladys NFT collection. The new BRC-721E standard enables the conversion of immutable, verifiable ERC-721 NFTs to Ordinals. Initially, metadata is not stored on-chain, but users can store a lower-quality preview image and include a reference to the Ether (ETH) burn in the raw image data.
The migration process starts by burning the ERC-721 NFT with an ETH call function. The burning of the NFT is an irreversible process and acts as an on-chain inscription method. To claim the ETH burn on Bitcoin, the user must inscribe valid BRC-721E data, after which the bridged NFT will appear on a custom Ordinals market collection page with complete metadata.
The indexers that check the burned NFT data inscriptions ensure that a token has no more than one valid inscription and that the genesis address matches the burn transaction call data.
The Ordinals market claimed the fundamental principles of BRC-721E and the flexibility of the indexers allow for the protocol to evolve over time, despite the fact that metadata is initially not stored on-chain.
Bitcoin Ordinals has attracted widespread reaction from the crypto community since its launch in January 2023. The launch of the BRC-20 token standard in March created an experimental fungible token standard designed specifically for the Bitcoin blockchain. The combination of BRC-20 with Ordinals opened new gates for minting tokens on the Bitcoin blockchain, with the crypto community seeing the emergence of many popular BRC-20 tokens, such as Ordinals (ORDI), Vmpx (VMPX) and Pepecoin (PEPE).
The number of BRC-20 tokens has skyrocketed from a few hundred in its first week to over 25,000 at the time of publication. However, the rise of Ordinals and the new token minting era has not been unanimously well-received, with many Bitcoin (BTC) proponents criticizing the new method as inefficient and wasteful.