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What is a soulbound token?
A soulbound token is an NFT that cannot be transferred or sold once it lands in a wallet. It is meant to record something about that account, such as attending an event, earning a credential or holding membership, rather than to be traded.
What it means for you
Because it cannot move, a soulbound token stays with the address: lose the keys and you lose it, and you cannot send it to a new wallet. What it records is public and tied to that address, so one linked to your identity can expose more about you than you intended.
A common mistake: “I can move my soulbound token to a new wallet if I switch.”
In fact: If it is locked under ERC-5192, every transfer function must fail. Whether a replacement can be issued to a new address is up to whoever issued it.
How it works
The idea comes from an essay by Vitalik Buterin, who argued that some things, such as proof of attending an event, a degree or governance rights, lose their meaning if they can be bought. ERC-5192 is a minimal standard on top of ERC-721: a locked function returns true when a token is bound, and while it is, every transfer function in the contract must fail. Contracts signal support through ERC-165 interface detection and emit Locked and Unlocked events, so wallets can show whether a token can move.
Sources: ERC-5192: Minimal Soulbound NFTs, Vitalik Buterin: Soulbound · checked 4 October 2026
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