Verify that Token is NFT

Question

I was wondering how it is possible to actually validate if a certain Token is an NFT without having to inspect the code of the script which mints that Token? Only by checking if the current quantity is 1 will certainly not ensure that it won't be possible to mint more of that Token.

Answer 1

You can check the token policy for that. For most NFT projects you can look it up on https://pool.pm

A token policy can look like this:

{
  "scripts": [
    {
      "keyHash": "66833acfcf26d87e56bc829aa7bcef13295d4eee4d8b442175bd67a9",
      "type": "sig"
    },
    {
      "slot": 31882046,
      "type": "before"
    }
  ],
  "type": "all"
}

You can see the "slot": 31882046 and "type": "before" values which means tokens with this policy can only be minted before slot 31882046. To be sure that your NFT is unique, you can check that the quantity is 1 and the current slot of the blockchain is later than the one mentioned in the policy.

This policy is from the following NFT: https://pool.pm/1131301ad4b3cb7deaddbc8f03f77189082a5738c0167e1772233097.CardanoBits1947