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Symbiosis BridgeV2 Contract
Symbiosis core smart contracts: BridgeV2 contract as a proxy between Synthesis/Portal contracts and the Symbiosis realayer network.
Symbiosis core smart contracts are open source and available at
https://github.com/symbiosis-finance/core-contracts
In the previous article: Symbiosis Mint-Burn Process, we explained the core idea of cross-chain operations:
- Whenever Portal locks tokens on one blockchain -> Synthesis mints tokens on another blockchain.
- Whenever Synthesis burns tokens on one blockchain -> Portal releases tokens on another blockchain.
Let's take a closer look at the BridgeV2 contract.
An instance of the BridgeV2 contract is deployed on each blockchain supported by Symbiosis and acts as a proxy between relayers and Portal/Synthesis contracts.
BridgeV2 accepts calls from:
- 1.The Portal/Synthesis contracts locked on the same blockchain: BridgeV2 issues an Oracle request (an event in terms of smart contracts) containing all the necessary data and instructions needed to accomplish the operation outside of the BridgeV2 blockchain.
- 2.Relayers: Transactions signed with MPC address. Such transactions contain data and instructions from another blockchain.
Scheme 1 below shows the BridgeV2 routine during cross-chain operations:

Scheme 1. BridgeV2 routine.
In addition, Portal/Synthesis uses BridgeV2 to store fees deducted from the users for cross-chain operations. Relayers transfer accumulated fees from BridgeV2 addresses to the addresses from which they send transactions. More information about fee collection can be found here: Gas Fees for Cross-chain Operations via Symbiosis.
About relayers. The Symbiosis relayers network is an off-chain part of the Symbiosis protocol. The main purpose of the network is to provide fast, accurate, and secure transfer of information about cross-chain operations conducted via the Symbiosis protocol. See Relayers network for more details.