> 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/standards/erc2477-token-metadata-integrity.md).

# ERC2477 Token Metadata Integrity

## Intro

Interface ERC

Defines mechanism by which clients (dapps) may verify that the token metadata has been delivered without unexpected manipulation.

Has two functions:

* tokenURIIntegrity
* tokenURISchemaIntegrity

Which defines how to add tokenURIIntegrity to metadata which is then added to Schema

### Solving problem

URLs (Uniform Resource Locators) provides no guarantees of storing metadata. This standard is providing access to assets on-chain.

### Standards that allows attaching metadata to specific tokens using URI:

* ERC721 metadata extension (`ERC721Metadata`)
* ERC1155 metadata extension (`ERC1155Metadata_URI`)
* EIP1046 Metadata extension (DRAFT) ERC-20 Metadata Extension

## Further reading

* Full implementation: <https://eips.ethereum.org/EIPS/eip-2477>
* Discussion: <https://github.com/ethereum/EIPs/issues/2483>