ERC-721 is a standard for creating non-fungible tokens (NFTs) on the Ethereum blockchain. Unlike fungible tokens, such as Ether or Bitcoin, NFTs represent unique assets that cannot be exchanged for one another.

The ERC-721 standard allows developers to create smart contracts that define the ownership and transfer of these unique digital assets, such as collectibles, virtual real estate, or artwork. Each NFT has a distinct identifier, making it impossible to duplicate or interchange with another asset.

One of the main benefits of ERC-721 is the ability to prove ownership and authenticity of a digital asset. This has led to a rise in popularity for NFTs, as they offer a new way to monetize digital content and provide a new level of value to creators.

However, as with any emerging technology, there are still challenges and limitations to consider. For example, the high gas fees on the Ethereum network can make it costly to mint and trade NFTs. Nonetheless, ERC-721 has opened up new possibilities for digital ownership and asset management on the blockchain.

ERC-721 stands for Ethereum Request for Comment 721, and it's a unique token standard on the Ethereum blockchain. Unlike traditional cryptocurrencies such as Bitcoin or even other Ethereum tokens, ERC-721 tokens are non-fungible tokens (NFTs). Non-fungible means that each token is distinct and cannot be replaced or exchanged on a one-to-one basis. ERC-721 tokens are often used to represent ownership or proof of authenticity of unique digital or physical assets, like digital art, collectibles, or real estate. The standard defines a set of rules and functions that developers follow when creating these tokens, ensuring interoperability and compatibility across various applications and platforms in the exciting and rapidly expanding world of blockchain-based assets.