# A primitive for tokens that own tokens

**URL:** <https://forum.openzeppelin.com/t/a-primitive-for-tokens-that-own-tokens/31563>\
**Category:** Smart Contracts\
**Tags:** erc721, erc1155\
**Created:** [August 30, 2022, 9:33pm UTC](https://forum.openzeppelin.com/t/a-primitive-for-tokens-that-own-tokens/31563 "2022-08-30T21:33:47Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Roy](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/roy/32/12910_2.png) [@Roy](https://forum.openzeppelin.com/u/Roy)\
**Post date:** [August 30, 2022, 9:33pm UTC](https://forum.openzeppelin.com/t/a-primitive-for-tokens-that-own-tokens/31563/1 "2022-08-30T21:33:47Z")

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Hello community 👋

I hope this forum is the right place for these kinds of messages...

On my last project I wrote an implementation for the ERC1155 contract that tracks the owner of a different token on an ERC721 contract (tokens owning tokens). It's great for attaching memberships directory to SBTs while allowing to easily rotate keys.

I was wondering where and how might be a best way to share that with the community.  
Since it's just a mod for an existing ERC I believe it won't qualify as a new ERC. I see may ERC variations are available here on OZ. Would you might be interested? 😊

> <https://github.com/VirtualBlock/ERC1155Tracker/blob/main/contracts/ERC1155TrackerUpgradable.sol>