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ICRC-7

Intermediate
Tokens

ICRC-7 defines a standard for non-fungible tokens (NFTs) on ICP and can be used to create a set of NFTs, also referred to as an NFT collection. It is a minimal standard and can be thought of as the equivalent of the ICRC-1 standard but for non-fungible tokens instead of fungible tokens. This base standard intentionally excludes some functions, such as:

  • Reliable transaction notifications for smart contracts.

  • A block structure and the interface for fetching blocks.

  • Pre-signed transactions.

ICRC-7 accounts have the same structure and follow the same overall principles as ICRC-1 accounts. ICRC-7 views the ICRC-1 Account as a primary concept, meaning that operations like transfers always refer to the full account and not only the principal portion. Some methods include an extra optional from_subaccount or spender_subaccount parameter that, together with the caller, forms an account to perform the respective operation on. Leaving such a subaccount parameter null is executed the same as referring to the default subaccount comprised of all zeroes.

Token metadata​

Available metadata entries for ICRC-7 tokens include:

  • icrc7:symbol: Type Text that defines the token's symbol, similar to a token's currency code.

  • icrc7:name: Type Text that defines the name of the token.

  • icrc7:description: Type Text that provides a description of the token.

  • icrc7:logo: Type Text, an optional URL of the token's logo image.

  • icrc7:total_supply: Type Nat: The current total number of tokens in existence.

  • icrc7:supply_cap: Type Nat, an optional maximum supply of tokens, after which minting new tokens is not possible.

Additional technical metadata elements can be found in the ICRC-7 specification.

Read the full ICRC-7 standard.