ResourcesThe OFT Standard
An Omnichain Fungible Token (OFT) is a new token standard that allows a token to exist natively on multiple blockchains. Unlike traditional bridges that create 'wrapped' versions of a token (like WETH), an OFT moves the actual supply between chains.
This ensures that a token on Arbitrum is exactly the same as the token on Ethereum, maintaining a unified supply and consistent utility across the entire ecosystem.
How OFTs Move: Burn & Mint
Traditional bridges use a 'Lock & Mint' model, which creates security risks if the bridge's central vault is compromised. LayerZero OFTs use a more elegant approach:
The cross-chain transfer process:
- Source Chain: The OFT is burned (destroyed) on the sending chain.
- Messaging: LayerZero sends a secure message to the destination chain confirming the destruction.
- Destination Chain: An equivalent amount of the native OFT is minted (created) and sent to the user's wallet.
For tokens that already exist and cannot be burned, developers use the 'OFT Adapter' which locks the original token in a vault on the main chain and mints OFTs on all other chains.
Technical Implementation
Building an OFT is simplified through the LayerZero Solidity contracts. Developers inherit the `OFT` or `OFTAdapter` contracts, which handle the complex messaging logic under the hood.
Key functions include `send()` for initiating transfers and `estimateSendFee()` to calculate the gas required across chains in the source chain's native currency.
Watch & Learn
Deep Dive into OFT V2
A technical walkthrough of deploying your first Omnichain token.
Challenge
Final quiz
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2 questions ยท Intermediate
What is the primary advantage of the Burn & Mint model over Lock & Mint?