The ERC-6454 Soulbound extension is a standard that enables the creation of non-transferable tokens. It provides various ways to make a token non-transferable:
Non-transferable from the moment they are minted.
Becoming non-transferable after a specified block.
Becoming non-transferable after a predefined number of transactions.
Setting tokens as non-transferable on a per-token basis.
Potential Use Cases
Verifiable attribution: NFTs can be used to represent personal achievements, but if these NFTs can easily be transferred, their authenticity can be questioned. Representing certifications, degrees or professional licenses in digital form are some potential applications.
Immutable properties: NFTs properties differentiate them and establish their scarcity. Ensuring these properties are unalterable by tying the NFT to certain properties provides uniqueness and prevents centralized control by the issuer.
Reputational avatars: NFTs can be accounts which are avatars, accruing reputation in the form of soulbound tokens inside the avatars (via ERC-6059). This makes it easy to collect badges, proof-of-attendance-protocols and even experience, skills, items, and more all in one NFT. Your avatar or wallet can still be transferred but is locked to that particular NFT. Furthermore, fully tradable game characters and on-chain trackable reputation will allow for easily enforceable meritocracy.
