How rarity is calculated?
Rarity is calculated using the published metadata of each NFT project. Inside the metadata for every NFT, there are a list of attributes. Every variant (ex. Crown) of every attribute (ex. Head) is added up then divided by the total number of NFTs minted. Finally, every attribute is divided by 1 and added up.
For me, explaining it is a bit more difficult than showing an example - Google Sheet Example
E2 = .0016 = 16 / 10000
G2 = .0016 = 16 / 10000
I2 = .0016 = 16 / 10000
K2 = .0016 = 16 / 10000
M2 = .0016 = 16 / 10000
O2 = .0016 = 16 / 10000
Q2 = .0016 = 16 / 10000
S2 = .936 = 9360 / 10000
U2 = .0001 = 1 / 10000
14376.068376068 = rarity score = (1/E2 + 1/G2 + 1/I2 + 1/K2 + 1/M2 +1/O2 + 1/Q2 + 1/S2 + 1/U2)
Most NFT series follow this formula. Some NFTs follow their own ranking structure. Several NFT series, Lawpunks, Cattos, and World of Masks, to name a few, have their own official ranking. They follow a similar, but slightly different formula due to extra attributes not in the metadata for Lawpunks, Cattos does not count total attributes, and World of Masks applies attributes with different weights. I've tweaked only Lawpunks and Cattos to to be close to the offical rank but it's off by a little from the offical rankings.
Why do some NFTs include a link to the original image url?
All NFT series pride themselves on their artwork. Large image files showcase the detail that they put into their work. The downside to these large files however is the filesize. Some series have filesizes of over 3MB per image. Loading 50 NFTs while browsing makes loadtimes take longer and chew through data, especially on mobile networks.
To speed things up and reduce bandwidth used, I've optimized images and reduced the filesize down ~95% from of the original filesize.
If any NFTs update their images, please submit an issue or pull request on GitHub. Additional repos will be posted in the README.md should this repo grow too large.
Who manages NFTRarity.cash?
I'm just a web-dev crypto enthusiast who's looking to have more in-depth knowledge of blockchain technologies.