In the Beta version of the protocol, the Inbox contract calls the functions natively using .Call This means that calls like transfer(address,uint256)transfer funds natively from the contract, requiring fillers to pre-fill the contract with a multi-call before calling fulfill. This is actually preferred as a default behavior, because calling arbitrary contracts with .delegateCall would create a high risk of fulling draining a solver if the arbitrary call contained malicious code. With .Call as the default, the solver must pre-fund the contract, and at most, only risks the funds that were prefilled.

This, however, is not with its drawbacks, specifically with respect to gas efficiency. Therefore, future versions of the protocol will also support .Call to give the solvers the ability to efficiently fill orders when the set of calls are on contracts they trust. The Inbox contract may also be extended to allow for helper contracts to fill on behalf of fillers.

Bonded ExclusivityERC-7683 Compliance