Token-2022 Program for fungible and non-fungible tokens
The Token-2022 Program is a token implementation for fungible and non-fungible tokens on the Solana blockchain. It is a superset of the existing Token Program, deployed on a different address, with new features added as extensions to mints and accounts. The program supports all the existing instructions and structure layouts of the Token Program, with new functionality added at a higher index. The Token-2022 program includes features such as confidential transfers, transfer fees, interest-bearing tokens, and immutable ownership. The source code is available on GitHub and the program is undergoing multiple security audits to ensure the safety of funds.
A token program on the Solana blockchain, defining a common implementation for fungible and non-fungible tokens.
The Token-2022 Program is a superset of the functionality provided by the Token Program, deployed to all networks.
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.
To make adoption as easy as possible, the functionality and structures in Token-2022 are a strict superset of Token.
Token-2022 supports the exact same instruction layouts as Token, byte for byte. For example, if you want to transfer 100 tokens on a mint with 2 decimals, you create a
TransferChecked instruction, with this byte-represented data:
[12, 100, 0, 0, 0, 0, 0, 0, 0, 2] ^^ TransferChecked enum ^^^^^^^^^^^^^^^^^^^^^^^^ 100, 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
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:
Account extensions currently include:
memo required on incoming transfers
default account state
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.
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.
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.
The Token-2022 Program is currently under multiple audits to ensure safety of funds. All audits will be published here as they are completed.
Here are the completed audits as of 12 December 2022:
Review commit hash
Review commit hash
Here are the ongoing audits:
Trail of Bits
Status and Upgradability
The Token-2022 program is still under audit and not meant for full production use. All clusters have the latest program deployed for testing and development purposes ONLY.
To facilitate deploying updates and security fixes, the program deployment remains upgradable. Once audits are complete, the deployment will be marked final and no further upgrades will be possible. This is expected to happen sometime in Q1 2023.