Offer types

1. Summary

A lender can choose between two types while making an offer. Basic and flexible.

2. Offer Types Detailed

Basic

The Basic offer is where the lender sets all loan parameters up-front and the borrower has an option to accept or not. Nothing else.

Offer struct has these properties:

Type	Name	Comment
address	collateralAddress	Address of an asset used as a collateral
MultiToken.Category (see MultiToken)	collateralCategory	Category of an asset used as a collateral (0 == ERC20, 1 == ERC721, 2 == ERC1155)
uint256	collateralAmount	The Amount of tokens used as collateral, in the case of ERC721 should be 1
uint256	collateralId	Token id of an asset used as collateral, in the case of ERC20 should be 0
address	loanAssetAddress	Address of an asset which is lent to a borrower
uint256	loanAmount	Amount of tokens which is offered as a loan to a borrower
uint256	loanYield	Amount of tokens that acts as a lender's loan interest. Borrower has to pay back borrowed amount + yield
uint32	duration	Loan duration in seconds
uint40	expiration	Offer expiration timestamp in seconds
address	lender	Address of a lender. This address has to sign an offer to be valid
bytes32	nonce	Additional value to enable identical offers in time. Without it, it would be impossible to make again an offer, which was once revoked

With the flexible offer struct, we change the collateralId, loanAmount, loanYield and duration parameters to a range of these parameters.

Flexible

With flexible offers, lenders can give borrowers additional flexibility by not providing concrete values but rather giving borrower ranges for several parameters. When accepting an offer, a borrower has to provide concrete values to proceed. This increases a lender's chance of accepting their offer as it could be accepted by more borrowers.

FlexibleOffer struct has these properties:

Type	Name	Comment
address	collateralAddress	Address of an asset used as a collateral
MultiToken.Category (see MultiToken)	collateralCategory	Category of an asset used as a collateral (0 == ERC20, 1 == ERC721, 2 == ERC1155)
uint256	collateralAmount	The Amount of tokens used as collateral, in the case of ERC721 should be 0
bytes32	collateralIdsWhitelistMerkleRoot	Root of a merkle tree constructed on an array of whitelisted collateral ids
address	loanAssetAddress	Address of an asset which is lent to a borrower
uint256	loanAmountMax	Max amount of tokens which is offered as a loan to borrower
uint256	loanAmountMin	Min amount of tokens which is offered as a loan to borrower
uint256	loanYieldMax	Amount of tokens which acts as a lender's loan interest for max duration.
uint32	durationMax	Maximal loan duration in seconds
uint32	durationMin	Minimal loan duration in seconds
uint40	expiration	Offer expiration timestamp in seconds
address	lender	Address of a lender. This address has to sign an offer to be valid.
bytes32	nonce	Additional value to enable identical offers in time. Without it, it would be impossible to make again an offer, which was once revoked

Flexible offers enable lenders to create an offer for a whole NFT collection.

Don't know what a merkle tree is? Read this article for more information.

Flexible offer values

When a borrower decides to accept a flexible offer they have to provide a specific representation of the offer. They do this by providing FlexibleOfferValues struct as the second argument for the createLoanFlexible function.

FlexibleOfferValues struct has these properties:

Type	Name	Comment
uint256	collateralId	Collateral token id. Ignored if it’s not a collection offer
uint256	loanAmount	Loan asset amount (always ERC20) in range <loanAmountMin; loanAmountMax>
uint32	duration	Offered loan duration in range <durationMin; durationMax>
bytes32[]	merkleInclusionProof	Proof that selected collateralId is indeed in the Merkle tree with root in signed flexible offer

How is the loan repay amount calculated?

$$loanRepayAmount = loanAmount + \frac{loanYieldMax*duration}{durationMax}$$

• loanAmount - Loan asset amount (always ERC20) in range <loanAmountMin; loanAmountMax>

• loanYieldMax - Amount of tokens which acts as a lender's loan interest for max duration

• duration - Offered loan duration in range <durationMin; durationMax>

• durationMax - Maximum loan duration in seconds