fa2

FA2 is a token standard on the Tezos blockchain that provides a common interface for handling multiple asset types. It is designed to support fungible tokens, non-fungible tokens (NFTs), and semi-fungible tokens within a single framework, offering a flexible and extensible alternative to earlier Tezos token standards.

The core goal of FA2 is to enable uniform interaction with different kinds of tokens through a small set of entry points. The primary entry points typically include transfer, balance_of, and update_operators. The transfer entrypoint allows batch transfers in a single call, enabling efficient multi-asset operations. balance_of is used for querying balances, while update_operators manages delegated transfer rights by allowing owners to authorize or revoke operators who can move tokens on their behalf.

Token identification in FA2 relies on a token_id, a natural number that identifies each asset within a contract. The contract stores balances in a ledger structure that maps token_id and holder to amounts, with a per-token metadata mechanism (token_metadata) to describe each asset. This design supports a wide range of token types and enables platforms to enumerate and display assets consistently.

FA2 is implemented as a Tezos standard, associated with the broader ecosystem concepts such as TZIP-12. It is commonly implemented in high-level languages like SmartPy and LIGO and compiled to Michelson for on-chain execution. FA2 has achieved broad adoption for projects issuing tokens, including NFT collections and multi-asset platforms, due to its flexibility and support for batch operations and operator-based approvals.

In summary, FA2 provides a versatile, multi-asset token standard for Tezos, emphasizing a unified interface, batch operations, and configurable ownership controls to support diverse token types and use cases.