user151: I realize that metadata for nfts has no official standard. However, many 3rd parties render nfts and their attributes which means they are reading meta data according to one or more schemas.
Here is an example of the zombie metadata:
{
   96580bbc4fe27ac0d127db3f8a0dc698c58d303d8cae870f5771f336: {
      ZombieChains00690: {
         Project: "Zombie Chains",
         attributes: {
            Background: "Purple",
            Chains: "None",
            Clothing: "Biker",
            Earrings: "None",
            Eyes: "Zombie",
            Hat: "Baseball",
            Mouth: "Stitches",
            Nose: "Solid",
            Skin: "Red",
            Weapon: "Sword"
         },
         copyright: "2021 Zombie Chains",
         image: "ipfs://QmQTkayfG1GWzenfEm65DLyYVL7MS6sSfWZQyPuFm6XiEV",
         name: "Zombie Chains #00690",
         twitter: "https://twitter.com/ZombieChains",
         type: "image/png",
         website: "https://zombiechains.io"
      },

Does anyone have documentation or knowledge about metadata nft standards?

user1231: There is a metadata standard. You can check it here: CIP-0025
{
  "721": {
    "<policy_id>": {
      "<asset_name>": {
        "name": <string>,

        "image": <uri | array>,
        "mediaType": "image/<mime_sub_type>",

        "description": <string | array>

        "files": [{
          "name": <string>,
          "mediaType": <mime_type>,
          "src": <uri | array>,
          <other_properties>
        }],

        <other properties>
      }
    }
    "version": "1.0"
  }
}

Not all follow that standard.

151: <p>I realize that metadata for nfts has no official standard. However, many 3rd parties render nfts and their attributes which means they are reading meta data according to one or more schemas.</p>
<p>Here is an example of the zombie metadata:</p>
<pre><code>{
   96580bbc4fe27ac0d127db3f8a0dc698c58d303d8cae870f5771f336: {
      ZombieChains00690: {
         Project: &quot;Zombie Chains&quot;,
         attributes: {
            Background: &quot;Purple&quot;,
            Chains: &quot;None&quot;,
            Clothing: &quot;Biker&quot;,
            Earrings: &quot;None&quot;,
            Eyes: &quot;Zombie&quot;,
            Hat: &quot;Baseball&quot;,
            Mouth: &quot;Stitches&quot;,
            Nose: &quot;Solid&quot;,
            Skin: &quot;Red&quot;,
            Weapon: &quot;Sword&quot;
         },
         copyright: &quot;2021 Zombie Chains&quot;,
         image: &quot;ipfs://QmQTkayfG1GWzenfEm65DLyYVL7MS6sSfWZQyPuFm6XiEV&quot;,
         name: &quot;Zombie Chains #00690&quot;,
         twitter: &quot;https://twitter.com/ZombieChains&quot;,
         type: &quot;image/png&quot;,
         website: &quot;https://zombiechains.io&quot;
      },
</code></pre>
<p>Does anyone have documentation or knowledge about metadata nft standards?</p>
 1231: <p>There is a metadata standard. You can check it here: <a href="https://github.com/cardano-foundation/CIPs/blob/master/CIP-0025/README.md" rel="noreferrer">CIP-0025</a></p>
<pre><code>{
  &quot;721&quot;: {
    &quot;&lt;policy_id&gt;&quot;: {
      &quot;&lt;asset_name&gt;&quot;: {
        &quot;name&quot;: &lt;string&gt;,

        &quot;image&quot;: &lt;uri | array&gt;,
        &quot;mediaType&quot;: &quot;image/&lt;mime_sub_type&gt;&quot;,

        &quot;description&quot;: &lt;string | array&gt;

        &quot;files&quot;: [{
          &quot;name&quot;: &lt;string&gt;,
          &quot;mediaType&quot;: &lt;mime_type&gt;,
          &quot;src&quot;: &lt;uri | array&gt;,
          &lt;other_properties&gt;
        }],

        &lt;other properties&gt;
      }
    }
    &quot;version&quot;: &quot;1.0&quot;
  }
}
</code></pre>
<p>Not all follow that standard.</p>
