ERC-721 vs ERC-1155 token IDs
ERC-721 tracks a distinct token owner by token ID. ERC-1155 tracks balances for accounts and IDs, allowing multiple units of an ID.
Worked example
| Question | ERC-721 | ERC-1155 |
|---|---|---|
| Ownership query | ownerOf(id) | balanceOf(account, id) |
| ID meaning | Distinct token in a contract | Token type/ID with per-account balances |
| Transfer data | One token ID per standard transfer | Single or batch ID/amount arrays |
Worked edition example
In an illustrative ERC-1155 contract, ID 7 might have 100 units distributed among accounts. An account holding 3 units is not the exclusive owner of ID 7. An ERC-721 ownerOf(7) instead returns a single owner for that existing token.
Do not infer supply from the standard
ERC-1155 permits different token models, including IDs with a supply of one. ERC-721 does not tell you how many IDs a particular collection has issued. Inspect the actual contract and documented collection design.
Common pitfalls
- An ID number alone says nothing about rarity.
- ERC-1155 support varies between wallets and import interfaces.
Related references
Primary sources
Examples explain identifiers. They are not investment recommendations.