# Bitcoin Token Standards

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* **What Are Token Standards?** Token standards are the set of rules, conditions, and functions that dictate how a crypto token works.
* Popular token standards on Ethereum are ERC-20, ERC-223 and ERC-721. Similarly, popular token standards on Bitcoin are BRC-20, BRC-223 and BRC-721.
* **What is Bitcoin Request for Comment (BRC)?** BRC is essentially a set of technical documents containing guidelines on developing a smart contract.