Bridge Mechanism
Multichain FRAX+FXS that is fungible across many networks
The Frax Protocol is a multichain protocol with global state consistent across all deployments. FRAX+FXS tokens are a single distribution across all networks. There is no independent Frax implementation for each chain. For this reason, the protocol has a bridging system that allows it to maintain a tight peg and fungibility in a unique & novel way.
The protocol treats each individual bridged FRAX/FXS as a unique liability of that bridge system and names FRAX/FXS moved from other chains with the identifier of that bridge. For example, AnySwap bridged FRAX is referred to as anyFRAX and FRAX bridged with the Wormhole bridge is called wormFRAX.
Each chain has 1 canonical FRAX and canonical FXS contract that are simply referred to as "FRAX" and "FXS" (with no prefix). These tokens are what AMOs expand/contract and users themselves can trustlessly mint/redeem.
Canonical (native) FRAX/FXS: The pure protocol liability natively issued/minted/redeemed by the protocol & AMOs. Canonical FRAX has the default colors of that specific network and the logo of that network at the center. Native FXS has the native colors and logo of the chain at the bottom right. Thus, any canonical/native FRAX/FXS always displays the network logo somewhere on the coin. Bridged FRAX/FXS: Tokens that are brought to the current chain from another network using a supported bridge protocol. The naming convention for bridged tokens maintains a prefix designation for the bridge used to bring them to the current network. Ex: AnySwap bridged FRAX from ETH to AVAX is known as anyFRAX on AVAX while it is simply canonical FRAX on ETH. The colors and logo of the bridge protocol are prominently display on the FRAX/FXS token to clearly distinguish which bridge they originated from within the current network.

Swapping FRAX/FXS and Peg Arbitrage Between Chains

Each canonical FRAX/FXS ERC20 token contract has a 1 to 1 stableswap AMM built into the token which allows swapping to/from the canonical FRAX/FXS of the network for any supported bridged FRAX/FXS. This allows tight arbitrage of the FRAX peg and also maintains the single distribution of FXS across all chains. For example, let's assume that canonical FRAX on Fantom is $.990. An arbitrager can purchase as much canonical FRAX as possible at $.990 knowing that she can swap them 1 to 1 for anyFRAX in the stableswap pool within the ERC20 token contract then bridge the anyFRAX back to ETH mainnet (or any other chain) where FRAX is at peg to make a profit. Therefore, purchasing canonical FRAX/FXS on one chain is the same as purchasing FRAX/FXS on another chain. If you bridge FRAX/FXS using any of the supported bridges (more to be added soon), you can swap the bridged token for native FRAX/FXS on that chain to farm/LP/hold etc. Additionally, when canonical FRAX/FXS is minted with AMOs on any chain, the protocol checks that there is enough swap liquidity available with the token contract to move canonical tokens across chains so that the peg is always global and arbitraged.
Swaps can be done any time at or interacting directly with the native token's smart contract on any chain. The swap mechanism is built into the native ERC20 FRAX/FXS tokens on every chain (except Ethereum L1).
Any example swap on of FRAX bridged from the Polygon PoS bridge (named polyFRAX) for canonical, native issued FRAX on Polygon.
An example swap on of AnySwap bridged FXS (named anyFXS) for canonical, native FXS on Fantom.


NOTE: This guide is for Fantom, but is applicable to other chains. For Polygon, use their proprietary bridge for the bridging step.
Guide: How to swap your bridged FRAX & FXS to canonical native tokens.

Canonical Token Addresses

Last modified 14h ago