What is the difference between ERC-20 and ERC-721 tokens?

ERC-20 and ERC-721 are both token standards on the Ethereum blockchain but serve different purposes. ERC-20 is a standard for fungible tokens, meaning that each token is identical in value and can be exchanged on a one-to-one basis with other tokens of the same type. Examples include stablecoins like USDT or governance tokens like UNI. On the other hand, ERC-721 is a standard for non-fungible tokens (NFTs), where each token represents a unique asset, such as digital artwork, collectibles, or virtual real estate. ERC-721 tokens are distinguishable from each other and cannot be exchanged on a one-to-one basis, making them ideal for creating unique items or assets in the digital space.