> For the complete documentation index, see [llms.txt](https://docs.stormbit.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stormbit.finance/developers/building-modules.md).

# Building Modules

Modules manage collateral for loans.

```solidity
interface ILoanModule {
    function setup(address caller, TermKey calldata termKey, bytes calldata data) external returns (bool);
    function verify(address caller, TermKey calldata termKey, LoanKey calldata loanKey, bytes calldata data) external returns (bool);
    function beforeLoan(address caller, LoanKey calldata loanKey, bytes calldata data) external returns (bool);
    function afterLoan(address caller, LoanKey calldata loanKey, bytes calldata data) external returns (bool);
    function liquidate(TermKey calldata termKey, LoanKey calldata loanKey, address beneficiary, uint256 repayment, bytes calldata data) external;
}
```

***

**setup()** — Configure module for a term

**verify()** — Validate loan parameters before allocation (must revert if unsafe)

**beforeLoan()** — Lock collateral from borrower

**afterLoan()** — Release collateral after settlement

**liquidate()** — Handle defaulted loans

***

**Built-in modules:** ERC20LTV (token collateral with LTV validation), ERC721 (NFT collateral for P2P lending), Attestation (identity/credential-based lending)

***

* Implement the interface above
* Validate thoroughly in `verify()`
* Only release collateral after confirming settlement
* Reference deployed contracts for implementation details


---

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