> For the complete documentation index, see [llms.txt](https://docs.xyxyx.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.xyxyx.pro/token-standards/erc-404.md). # ERC-404 The [ERC-404](https://github.com/Pandora-Labs-Org/erc404) is a hybrid token standard that combines the functionalities of the ERC-721 standard (non-fungible tokens) and the ERC-20 standard (fungible tokens). This means that ERC-404 smart contracts can be seamlessly integrated into any ERC-20 or ERC-721 application (i.e., Uniswap or OpenSea). By combining the functionalities of both ERC-721 and ERC-20 tokens standards, ERC-404 smart contracts can be highly customizable in defining token economics, which can range from unique, indivisible items (`0` decimals) to widely distributable assets with varying levels of granularity (from `1` to `18` decimals). Xyxyx introduces a fully blockchain-based version of the ERC-404 standard, featuring native Base64-encoded SVG outputs as the `tokenURI`. * [Parameters](/token-standards/erc-404/parameters.md) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.xyxyx.pro/token-standards/erc-404.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.