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Token-2022 Program

A token program on the Solana blockchain, defining a common implementation for fungible and non-fungible tokens.

The Token-2022 Program, also known as Token Extensions, is a superset of the functionality provided by the Token Program.

InformationAccount Address
Token-2022 ProgramTokenzQdBNbLqP5VEhdkAS6EPFLC1PHnBqCXEpPxuEb

Motivation​

The existing Token Program serves most needs for fungible and non-fungible tokens on Solana through a simple set of interfaces and structures. It has been rigorously audited since its initial deployment in 2020.

As more developers have come to Solana with new ideas, however, they have forked the Token Program to add functionality. It's simple to change and deploy the program, but it's difficult to achieve adoption across the ecosystem.

Solana's programming model requires programs to be included in transactions along with accounts, making it complicated to craft transactions involving multiple token programs.

On top of the technical difficulty, wallets and on-chain programs must trust any token program that they choose to support.

We need to add new token functionality, with minimal disruption to users, wallets, and dApps. Most importantly, we must preserve the safety of existing tokens.

A new token program, Token-2022, was developed to achieve both of these goals, deployed to a different address than the Token program.

Concept​

To make adoption as easy as possible, the functionality and structures in Token-2022 are a strict superset of Token.

Instructions​

Token-2022 supports the exact same instruction layouts as Token, byte for byte. For example, if you want to transfer 0.75 tokens in UI amount, on a mint with 2 decimals, then the transfer amount is 75 tokens. You create a TransferChecked instruction, with this byte-represented data:

[12, 75, 0, 0, 0, 0, 0, 0, 0, 2]
 ^^ TransferChecked enum
     ^^^^^^^^^^^^^^^^^^^^^^^^ 75, as a little-endian 64-bit unsigned integer
                               ^ 2, as a byte

This format means the exact same thing to both Token and Token-2022. If you want to target one program over another, you just need to change the program_id in the instruction.

All new instructions in Token-2022 start where Token stops. Token has 25 unique instructions, with indices 0 through 24. Token-2022 supports all of these instructions, and then adds new functionality at index 25.

There are no plans to ever add new instructions to Token.

Mints and Accounts​

For structure layouts, the same idea mostly applies. An Account has the same exact representation between Token and Token-2022 for the first 165 bytes, and a Mint has the same representation for the first 82 bytes.

Extensions​

New functionality requires new fields in mints and accounts, which makes it impossible to have the exact same layout for all accounts in Token-2022.

New fields are added in the form of extensions.

Mint creators and account owners can opt-in to Token-2022 features. Extension data is written after the end of the Account in Token, which is the byte at index 165. This means it is always possible to differentiate mints and accounts.

You can read more about how this is done at the source code.

Mint extensions currently include:

  • confidential transfers
  • transfer fees
  • closing mint
  • interest-bearing tokens
  • non-transferable tokens
  • permanent delegate
  • transfer hook
  • metadata pointer
  • metadata

Account extensions currently include:

  • memo required on incoming transfers
  • immutable ownership
  • default account state
  • CPI guard

Extensions can be mixed and matched, which means it's possible to create a mint with only transfer fees, only interest-bearing tokens, both, or neither!

Associated Token Accounts​

To make things simpler, there is still only one associated token account program, that creates new token accounts for either Token or Token-2022.

Getting Started​

To get started with Token-2022:

For existing functionality in the Token Program, see the token docs. The Token functionality will always apply to Token-2022.

Source​

The Token-2022 Program's source is available on GitHub.

For information about the types and instructions, the Rust docs are available at docs.rs.

Security Audits​

The Token-2022 Program has been audited multiple times. All audits are published here as they are completed.

Here are the completed audits as of 13 December 2023: