Cross-chain Swaps

Natively Cross-chain

Bazaar natively integrates the Across Protocol and Across+ to power intent-centric, cross-chain swaps – allowing the protocol to be seamlessly integrated across Ethereum and various L2 networks. As a truly chain-agnostic protocol, Bazaar enables its users to participate in launches from any integrated network with a single transaction from their source chain of choice.

When a user signs a cross-chain transaction, a Gas Subsidy Fee is taken out of their input token balance (i.e. USDC) to ensure seamless execution of the swap on the destination chain. Bazaar currently supports cross-chain swaps from Ethereum, Arbitrum One, Optimism, Base, Polygon POS, and ZkSync Era, with support for additional networks in the near future.

What is Across Protocol?

Across is an interoperability protocol powered by intents. It is the only cross-chain intents protocol in production today, enabling the fastest and lowest-cost interoperability solution without security tradeoffs. Bazaar, by utilizing Across' composable bridging, enables swaps to be executed atomically with the bridge (fill) transaction on the destination chain.

Source: Across V3 Intents Bridging

For more detailed information on Across mechanics, refer to the official Across protocol documentation: https://docs.across.to/introduction/what-is-across

Bazaar's Across+ integration works by providing a public utility -- AcrossSwapHandler -- that implements the Across+ abstraction, allowing users to atomically bridge funds and swap into the specified LBP in a single transaction. This effectively works by having the user bridge funds directly to the `AcrossSwapHandler` address with an abi-encoded message following the format:

 ```solidity
abi.encode(lbpPoolId, recipientAddress, tokenAddressOut, minAmountOut)
 ```
On recipient of this message, the `AcrossSwapHandler` will attempt a swap on the LBP with the provided funds, destination address, and slippage requirements.
* On swap **success**, swapped funds are transferred directly to the recipient address
* On swap **failure**, the bridged funds are simply forwarded to the recipient address.
The status of this atomic transaction can be tracked by inspecting the logs of the transaction filled by the relayer on the destination chain
```solidity
event AcrossSwap(bytes32 poolId, address recipient, address tokenBridged, uint256 amount, bool success);
```
_Note: The `AcrossSwapHandler` is compatible with both the Across V2 and upcoming V3 implementation_ // Some code

When a cross-chain swap transaction is executed, it's possible that the swap transaction following the bridge transaction reverts for a number of reasons, including insufficient liquidity or inadequate slippage settings. This would result in the funds being transferred to the recipient address on the destination chain, and will require a separate transaction to ensure a successful swap from the quote token to the sale token.

In the future, Bazaar may add support for additional interoperability solutions to enable support and cross-chain routing for additional Layer 1 and Layer 2 networks.