Polarizer.json 🕶

Polarizer is a JSON-formatted registry file that enables someone to describe NFTs within a given wallet that should and should not be displayed.

Why is this needed?

Anyone can deposit NFTs into any other wallet, without requiring anyone's permission to do so. As a result, a wallet may contain some NFTs that its owner may not want to showcase. With open ledgers, it's possible for a website to view and showcase all NFTs owned by a given wallet. While some websites may have built-in ways to hide specific assets, there needs to be an open standard that websites can adopt which instructs front-ends on which NFTs should or should not be displayed.

Some additional reasons include:

• It may be costly to try and send away undesireable NFTs
• Some NFTs may be hard coded as "non-transferrable" meaning they can't be sent away at all

How does Polarizer work?

Polarizer is a simple .json file that defines which NFTs, and NFT contracts should be allowed or disallowed from display. Here is its basic formatting:

{
  "name": "Polarizer.json",
  "version": 0.1,
  "allowed": [
  ],
  "blocked": [
  ]
}

• version: This indicates which version of the Polarizer format is in use
• allowed: An array of addresses that refer to individual NFTs, or NFT contract that should be displayed. Note that if any address is present in allowed, only those addresses should be displayed
• blocked: An array of NFTs or contracts that should not be displayed.

Example:

{
  "name": "Polarizer.json",
  "version": 0.1,
  "allowed": [
  ],
  "blocked": [
    0x6c94954d0b265f657a4a1b35dfaa8b73d1a3f199
  ]
}

View an example here, as published on IPFS.

In the above example, all NFTs contained within the wallet would be displayed except the ones in the blocked array. The address listed in this example is a token contract, meaning that all NFTs minted via that contract would not be displayed.

Where is a polarizer.json file stored?

It can be stored anywhere, really. A useful choice might be IPFS. In practice, perhaps it could be referred to in the corresponding ENS domain for a given wallet address.

How can websites support Polarizer?

Let's figure it out! All a website would need to do is read a given wallet's polarizer.json file, but we need to come up with a standard set of locations for the website to check against.

Why is it called Polarizer?

"Polarizer" refers to polarization, which is a technique used in sunglasses and other applications to permit certain waves of light, but not others.