In OpenSea documentation is said that Collections are used to represent all the assets in a single (or multiple) contract addresses and help users group items from the same creator.
Collection has primary_asset_contracts attribute with description "A list of the contracts that are associated with this collection".
But there is neither API, neither UI solution to include additional contract address to collection. So how collection with more than one contract address can be created?
This is the answer I got from OpenSea support:
Hi there, Thanks for reaching out. We would be able to merge collections on our end if its owned by the same creator. If you have multiple collections, we could merge it under on slug an example of a slug would be (brkfst-world); https://opensea.io/collection/brkfst-world If this is something your interested in doing please include a link to each of the collections and the slug you'd like to merge it under. Kind regards, OpenSea Customer Experience Associate
Merge into one collection can't be done using API or UI, but OpenSea can do it on their end if they are contacted.
primary_asset_contractsor do I have to be the owner? This section of the docs says "many ERC-721 contracts may all belong to the same collection (dapp)". So I think it is possible. I addedprimary_asset_contractsand added an array of ERC721 addresses owned, minted and deployed by the same address but it doesn't seem to work..primary_asset_contractsis only mentioned in the API docs. So I think it's an internal key OpenSea uses to create collections for the same issuer. But a collection itself only has one contract in it.