OFT Variants

Stablecoin OFT provides multiple OFT variants to support different token economics and deployment scenarios. Each variant implements a different cross-chain transfer model. All share the same extension stack (fee, rate limiting, pause).

Decision Matrix

Scenario	OFT	Why
Token with permissioned burn and mint	`OFTBurnMint`	Burn on source, mint on destination. No locked collateral.
Token with permissionless self-burn and permissioned mint	`OFTBurnSelfMint`	Transfers to OFT via allowance, then self-burns. Mint on destination.
Existing token with supply on one chain	`OFTLockUnlock`	Lock on source, unlock on destination. No supply change.
Native gas token (ETH, MATIC, etc.)	`OFTNative`	Wraps `msg.value` for cross-chain transfer.
Target chain uses ERC20 for gas fees	Alt variants	Same logic but built for `EndpointV2Alt`.

OFTBurnMint

Burns tokens on the source chain and mints them on the destination chain. Supports any token that exposes mint and burn functions with (address, uint256) parameters. The OFT must be granted the required roles (e.g., MINTER_ROLE, BURNER_ROLE) to call these functions. Key feature: Configurable function selectors allow the OFT to call non-standard mint/burn function names.

Constructor Parameters

Parameter	Type	Description
`_token`	`address`	Underlying ERC20 token address (must implement `IERC20Metadata`)
`_burnerMinter`	`address`	Contract with burn/mint capabilities (can differ from `_token`)
`_endpoint`	`address`	LayerZero EndpointV2 address
`_approvalRequired`	`bool`	Whether the OFT needs ERC20 approval to burn
`_burnSelector`	`bytes4`	Function selector for burn, e.g., `0x9dc29fac` for `burn(address,uint256)`
`_mintSelector`	`bytes4`	Function selector for mint, e.g., `0x40c10f19` for `mint(address,uint256)`
`_rateLimiterScaleDecimals`	`uint8`	Decimals to scale rate limit amounts (usually `0`)

Common Selector Values

Function Signature	Selector
`mint(address,uint256)`	`0x40c10f19`
`burn(address,uint256)`	`0x9dc29fac`
`issue(address,uint256)`	`0x867904b4`
`redeem(address,uint256)`	`0x1e9a6950`

Initialization Parameters

Parameter	Type	Description
`_initialAdmin`	`address`	Address to be granted `DEFAULT_ADMIN_ROLE` and endpoint delegate
`_feeDeposit`	`address`	Address that will receive any accrued fees

function initialize(address _initialAdmin, address _feeDeposit) public initializer;

OFTBurnSelfMint

For tokens with a permissionless self-burn function (e.g., OpenZeppelin’s ERC20Burnable.burn(uint256)) and a permissioned mint function. On the send path, the OFT transfers tokens from the user to itself via ERC20 allowance, then calls the self-burn selector to destroy them. On the receive path, it mints via the mint selector like OFTBurnMint.

Constructor Parameters

Parameter	Type	Description
`_token`	`address`	Token address that is also the burner/minter
`_endpoint`	`address`	LayerZero EndpointV2 address
`_burnSelector`	`bytes4`	Function selector for burn
`_mintSelector`	`bytes4`	Function selector for mint
`_rateLimiterScaleDecimals`	`uint8`	Decimals to scale rate limit amounts

Common Selector Values for OFTBurnSelfMint

Function Signature	Selector
`mint(address,uint256)`	`0x40c10f19`
`burn(uint256)`	`0x42966c68`
`issue(address,uint256)`	`0x867904b4`
`redeem(uint256)`	`0xdb006a75`

OFTLockUnlock

Locks tokens in the OFT contract on the source chain and unlocks (transfers) them from the OFT on the destination chain. No minting or burning occurs.

Constructor Parameters

Parameter	Type	Description
`_token`	`address`	Underlying ERC20 token address (must implement `IERC20Metadata`)
`_endpoint`	`address`	LayerZero EndpointV2 address
`_rateLimiterScaleDecimals`	`uint8`	Decimals to scale rate limit amounts

approvalRequired is always true for lock/unlock since users must approve the OFT to transfer their tokens.

Only one lock/unlock OFT should exist per OFT mesh. If multiple lock/unlock OFTs exist on different chains, locked supply becomes fragmented and the system cannot guarantee solvency.

OFTNative

Wraps native tokens (ETH, MATIC, AVAX, etc.) for cross-chain transfer. Users send native tokens as msg.value along with the send() call.

Constructor Parameters

Parameter	Type	Description
`_localDecimals`	`uint8`	Decimals of the native token (18 for ETH)
`_endpoint`	`address`	LayerZero EndpointV2 address
`_rateLimiterScaleDecimals`	`uint8`	Decimals to scale rate limit amounts

Send Behavior

The overridden send() function validates that msg.value equals exactly _fee.nativeFee + _sendParam.amountLD:

uint256 requiredMsgValue = _fee.nativeFee + _sendParam.amountLD;
if (msg.value != requiredMsgValue) {
    revert IncorrectMessageValue(msg.value, requiredMsgValue);
}

Receive Behavior

Credits are sent as native token transfers using low-level .call{value}(). If the transfer fails (e.g., recipient is a contract without a receive function), the transaction reverts with CreditFailed(to, amountLD, revertData).

Properties

token() returns address(0) since there is no ERC20 token
approvalRequired() returns false since msg.value is used directly
Dust removal is not applied to amountLD since native token amounts always equal amountSentLD

Alt Variants

Some chains use an ERC20 token for gas fees instead of a native token. Because gas fees are paid in an ERC20, the sender must approve the endpoint to spend the fee token before sending a message. This changes the standard send() workflow: users need an additional ERC20 approval step for the fee token, and the endpoint pulls fees via transferFrom rather than accepting msg.value. These chains use EndpointV2Alt instead of EndpointV2 to handle this difference. The Alt OFT variants are identical to their standard counterparts except they target EndpointV2Alt:

Standard Variant	Alt Variant
`OFTBurnMint`	`OFTBurnMintAlt`
`OFTBurnSelfMint`	`OFTBurnSelfMintAlt`
`OFTLockUnlock`	`OFTLockUnlockAlt`

Alt variants inherit from the corresponding ExtendedRBACAltUpgradeable contracts. Constructor parameters and behavior are otherwise the same.

Multi-Chain Topology

Burn/Mint

        +--------------+     +--------------+
        |  Chain A     |<--->|  Chain B     |
        | OFTBurnMint  |     | OFTBurnMint  |
        +------+-------+     +------+-------+
               |                    |
               +---------+----------+
                         |
                 +--------------+
                 |  Chain C     |
                 | OFTBurnMint  |
                 +--------------+

All chains are equal peers. Each OFT burns on send and mints on receive. Total supply across all chains stays constant. Works the same way with OFTBurnSelfMint.

Lock/Unlock

        +--------------+     +--------------+
        |  Chain B     |     |  Chain C     |
        | OFTBurnMint  |     | OFTBurnMint  |
        +------+-------+     +------+-------+
               |                     |
               +----------+----------+
                          |
                 +----------------+
                 |  Chain A       |
                 | OFTLockUnlock  |
                 +----------------+

One chain (the token’s home chain) deploys OFTLockUnlock, which locks tokens on send and unlocks on receive. All other chains deploy OFTBurnMint, which burns on send and mints on receive. This keeps a single pool of locked collateral on Chain A backing all circulating supply on remote chains.

Next Steps

Extensions for fee, rate limiting, and pause configuration
RBAC Reference for roles on extended OFTs

LayerZero for EVM

Contract Standards

Stablecoin OFT

Tokenized RWAs OFT

Technical Reference

Troubleshooting

Resources

Decision Matrix

OFTBurnMint

Constructor Parameters

Common Selector Values

Initialization Parameters

OFTBurnSelfMint

Constructor Parameters

Common Selector Values for OFTBurnSelfMint

OFTLockUnlock

Constructor Parameters

OFTNative

Constructor Parameters

Send Behavior

Receive Behavior

Properties

Alt Variants

Multi-Chain Topology

Burn/Mint

Lock/Unlock

Next Steps

​Decision Matrix

​OFTBurnMint

​Constructor Parameters

​Common Selector Values

​Initialization Parameters

​OFTBurnSelfMint

​Constructor Parameters

​Common Selector Values for OFTBurnSelfMint

​OFTLockUnlock

​Constructor Parameters

​OFTNative

​Constructor Parameters

​Send Behavior

​Receive Behavior

​Properties

​Alt Variants

​Multi-Chain Topology

​Burn/Mint

​Lock/Unlock

​Next Steps

Decision Matrix

OFTBurnMint

Constructor Parameters

Common Selector Values

Initialization Parameters

OFTBurnSelfMint

Constructor Parameters

Common Selector Values for OFTBurnSelfMint

OFTLockUnlock

Constructor Parameters

OFTNative

Constructor Parameters

Send Behavior

Receive Behavior

Properties

Alt Variants

Multi-Chain Topology

Burn/Mint

Lock/Unlock

Next Steps