Too Long; Didn't Read
ERC721 is a free, open standard that describes how to build non-fungible or unique tokens on the Ethereum blockchain. While most of the tokens are fungible in nature, all are unique and often treated as collectibles. There are various types of tokens being used across the cryptocurrency industry and there are different ways to differentiate between tokens. The tokens are created on top of a blockchain using its own pre-designed templates and used in the execution of smart contracts, decentralizes applications and facilitate transactions. Such crypto tokens are usually created, bought, distributed and circulated through ICO.