> For the complete documentation index, see [llms.txt](https://nft-standards.gitbook.io/nft-standards-wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nft-standards.gitbook.io/nft-standards-wiki/custom-nft-platforms-add-ons/opensea.md).

# OpenSea

## Intro

OpenSea has decided to go this way: if the content pointed by the property “animation\_url” is HTML, they copy the HTML content to their server, and when the NFT is viewed on their website, they load this content.

This is a very easy implementation that works for some use cases, but it is not very flexible and works only for the basic use cases.

* For example, is the NFT distributor updates the code, they would expect the NFT to show the update automatically
* Another example, if the NFT code is in a directory and references things like “./images/my-image.jpg”, this will not work except if the whole directory is copied (which can be either impossible or a hassle and is prompt to errors).
* If the code needs its metadata or any other data to work, but the metadata changes over time, that might not be reflected and break the NFT

## Standards implementation

* ERC1155 implementation - overview: <https://github.com/ProjectOpenSea/opensea-erc1155>
* ERC-1155 implementation - full: <https://github.com/ProjectOpenSea/multi-token-standard>
* ERC-1155 tutorial (coming soon): <https://docs.opensea.io/docs/opensea-erc1155-tutorial>
* ERC721 tutorial: <https://docs.opensea.io/docs/getting-started>
* OpenSea NFT Metadata implementation: <https://hackmd.io/@Bnkhqf0tSbi1lX2Xc-WXYQ/ByxXJK-JK>