Magic Eden Polygon Marketplace has its own version of rarity for NFTs, which is calculated using an open-source tool called OpenRarity. OpenRarity is a rarity protocol built for the NFT community, which provides a transparent rarity calculation that is entirely open-source and reproducible. This purpose of this is to provide a consistent set of rarity rankings across all platforms to help build more trust and transparency in the NFT space.

OpenRarity calculates the rarity score of an NFT collection by analyzing various attributes of the collection such as the number of total supply, the number of unique traits, and the number of traits per NFT. The score is then used to determine the rarity rank of each NFT in the collection.

OpenRarity is built using Python, Poetry, Numpy, and PyTest, and licensed under Apache 2.0. OpenRarity welcomes contributions from the community and aims to be the open means of rarity calculation for the NFT industry.