# LendFactory > The `LendFactory` is the entry point for **creating new one-way lending markets**. It deploys a triplet of contracts — [Vault](./vault.md), [LendController](./lend-controller.md), and [AMM](./amm.md) — from blueprint implementations stored in an internal registry. Each market is fully isolated. # LendFactory The `LendFactory` is the entry point for **creating new one-way lending markets**. It deploys a triplet of contracts — [Vault](./vault.md), [LendController](./lend-controller.md), and [AMM](./amm.md) — from blueprint implementations stored in an internal registry. Each market is fully isolated. The factory uses Snekmate's [`ownable`](https://github.com/pcaversaccio/snekmate) module for access control and [`pausable`](https://github.com/pcaversaccio/snekmate) for emergency pause functionality. :::vyper[`LendFactory.vy`] The source code for the `LendFactory.vy` contract can be found on [GitHub](https://github.com/curvefi/curve-stablecoin/blob/master/curve_stablecoin/lending/LendFactory.vy). The contract is written in [Vyper](https://vyperlang.org/) version `0.4.3`. *Deployment addresses will be added once contracts are finalized.* ::: Examples use Ethers v6 with an ABI generated from the pinned source linked in each panel. Replace every zero address and amount placeholder. Read-only calls use the verified Ethereum v2 reference factory; execute a write only on a fork first. --- ## Market Creation ### `create` ::::description[`LendFactory.create(_borrowed_token: address, _collateral_token: address, _A: uint256, _fee: uint256, _loan_discount: uint256, _liquidation_discount: uint256, _price_oracle: address, _monetary_policy: address, _supply_limit: uint256) -> address[3]`] Deploys a new lending market by creating a Vault, LendController, and AMM from their respective blueprints. Validates all parameters, initializes the triplet, and registers the market. | Input | Type | Description | | --- | --- | --- | | `_borrowed_token` | `address` | Token that lenders deposit and borrowers receive | | `_collateral_token` | `address` | Token used as collateral by borrowers | | `_A` | `uint256` | Amplification coefficient — determines band width (~1/A) | | `_fee` | `uint256` | Swap fee for the AMM | | `_loan_discount` | `uint256` | Maximum discount for LTV calculation | | `_liquidation_discount` | `uint256` | Discount at which liquidation can occur | | `_price_oracle` | `address` | Initialized price oracle contract | | `_monetary_policy` | `address` | Initialized monetary policy contract | | `_supply_limit` | `uint256` | Maximum supply cap for the vault | Returns: array of three addresses — `[vault, controller, amm]` (`address[3]`). Emits: `NewVault` event. Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external def create( _borrowed_token: IERC20, _collateral_token: IERC20, _A: uint256, _fee: uint256, _loan_discount: uint256, _liquidation_discount: uint256, _price_oracle: IPriceOracle, _monetary_policy: IMonetaryPolicy, _supply_limit: uint256, ) -> address[3]: """ @notice Creation of the vault using user-supplied price oracle contract @param _borrowed_token Token which is being borrowed @param _collateral_token Token used for collateral @param _A Amplification coefficient: band size is ~1//A @param _fee Fee for swaps in AMM (for ETH markets found to be 0.6%). Bounds are enforced by the AMM: MIN_FEE <= _fee <= min(WAD * MIN_TICKS / _A, 10%) @param _loan_discount Maximum discount. LTV = sqrt(((A - 1) // A) ** 4) - loan_discount @param _liquidation_discount Liquidation discount. LT = sqrt(((A - 1) // A) ** 4) - liquidation_discount @param _price_oracle Custom price oracle contract @param _monetary_policy Monetary policy contract to set the borrow rate @param _supply_limit Supply cap @return Addresses of the deployed [vault, AMM, controller] contracts """ pausable._require_not_paused() assert _borrowed_token != _collateral_token, "Same token" assert _A >= MIN_A and _A <= MAX_A, "Wrong A" assert _liquidation_discount > 0, "liquidation discount = 0" assert _loan_discount < WAD, "loan discount >= 100%" assert _loan_discount > _liquidation_discount, "loan discount <= liquidation discount" A_ratio: uint256 = 10**18 * _A // (_A - 1) # Validate price oracle p: uint256 = (staticcall _price_oracle.price()) assert p > 0 # dev: price oracle returned zero # … the remaining implementation is linked above. ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, signer) const tx = await contract.create( /* _borrowed_token: address */ "0x0000000000000000000000000000000000000000", /* _collateral_token: address */ "0x0000000000000000000000000000000000000000", /* _A: uint256 */ 0n, /* _fee: uint256 */ 0n, /* _loan_discount: uint256 */ 0n, /* _liquidation_discount: uint256 */ 0n, /* _price_oracle: address */ "0x0000000000000000000000000000000000000000", /* _monetary_policy: address */ "0x0000000000000000000000000000000000000000", /* _supply_limit: uint256 */ 0n, ) await tx.wait() ``` :::: --- ## Market Registry ### `market_count` ::::description[`LendFactory.market_count() -> uint256: view`] Returns the total number of lending markets created by the factory. Returns: number of markets (`uint256`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def market_count() -> uint256: return len(self._vaults) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.market_count() ``` :::: ### `markets` ::::description[`LendFactory.markets(_n: uint256) -> Market: view`] Returns the market info struct for a given market index. | Input | Type | Description | | --- | --- | --- | | `_n` | `uint256` | Market index (0-based) | Returns: market struct containing the vault, controller, AMM, collateral-token, borrowed-token, price-oracle, and monetary-policy addresses (`Market`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view @reentrant def markets(_n: uint256) -> ILendFactory.Market: """ @notice Get market data for market at index `_n` @param _n Index of the market @return Market struct containing vault, controller, amm, tokens, price oracle and monetary policy addresses """ vault: IVault = self._vaults[_n] controller: IController = staticcall vault.controller() amm: IAMM = staticcall vault.amm() return ILendFactory.Market( vault=vault, controller=controller, amm=amm, collateral_token=staticcall vault.collateral_token(), borrowed_token=staticcall vault.borrowed_token(), price_oracle=staticcall amm.price_oracle_contract(), monetary_policy=staticcall controller.monetary_policy(), ) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.markets( /* _n: uint256 */ 0n, ) ``` :::: ### `coins` ::::description[`LendFactory.coins(_vault_id: uint256) -> IERC20[2]: view`] Returns the borrowed and collateral token addresses for a given vault. | Input | Type | Description | | --- | --- | --- | | `_vault_id` | `uint256` | Vault index | Returns: array of `[borrowed_token, collateral_token]` (`IERC20[2]`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view @reentrant def coins(_vault_id: uint256) -> IERC20[2]: vault: IVault = self._vaults[_vault_id] return [staticcall vault.borrowed_token(), staticcall vault.collateral_token()] ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.coins( /* _vault_id: uint256 */ 0n, ) ``` :::: ### `vaults_index` ::::description[`LendFactory.vaults_index(_vault: IVault) -> uint256: view`] Returns the index of a vault in the factory registry. Reverts if the vault is not registered. | Input | Type | Description | | --- | --- | --- | | `_vault` | `IVault` | Vault address to look up | Returns: vault index (`uint256`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view @reentrant def vaults_index(_vault: IVault) -> uint256: """ @notice Get the index of a vault in the markets array @param _vault Address of the vault @return Index of the vault """ return self._vaults_index[_vault] - 2**128 ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.vaults_index( /* _vault: IVault */ "0x0000000000000000000000000000000000000000", ) ``` :::: --- ## Blueprints ### `amm_blueprint` ::::description[`LendFactory.amm_blueprint() -> address: view`] Returns the current AMM blueprint address used for deploying new markets. Returns: blueprint address (`address`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def amm_blueprint() -> address: """ @notice Get the address of the AMM blueprint @return Address of the AMM blueprint """ return blueprint_registry.get(AMM_BLUEPRINT_ID) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.amm_blueprint() ``` :::: ### `controller_blueprint` ::::description[`LendFactory.controller_blueprint() -> address: view`] Returns the current controller blueprint address. Returns: blueprint address (`address`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def controller_blueprint() -> address: """ @notice Get the address of the controller blueprint @return Address of the controller blueprint """ return blueprint_registry.get(CONTROLLER_BLUEPRINT_ID) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.controller_blueprint() ``` :::: ### `vault_blueprint` ::::description[`LendFactory.vault_blueprint() -> address: view`] Returns the current vault blueprint address. Returns: blueprint address (`address`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def vault_blueprint() -> address: """ @notice Get the address of the vault blueprint @return Address of the vault blueprint """ return blueprint_registry.get(VAULT_BLUEPRINT_ID) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.vault_blueprint() ``` :::: ### `controller_view_blueprint` ::::description[`LendFactory.controller_view_blueprint() -> address: view`] Returns the current controller view blueprint address. Returns: blueprint address (`address`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def controller_view_blueprint() -> address: """ @notice Get the address of the controller view blueprint @return Address of the controller view blueprint """ return blueprint_registry.get(CONTROLLER_VIEW_BLUEPRINT_ID) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.controller_view_blueprint() ``` :::: --- ## Fee Receivers ### `fee_receiver` ::::description[`LendFactory.fee_receiver(_controller: address) -> address: view`] Returns the fee receiver for a given controller. If a custom fee receiver is set, it returns that; otherwise, it returns the default fee receiver. | Input | Type | Description | | --- | --- | --- | | `_controller` | `address` | Controller address | Returns: fee receiver address (`address`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def fee_receiver(_controller: address = msg.sender) -> address: """ @notice Get fee receiver who earns interest from admin fees @dev This function is called by controllers without specifying the first argument to get their fee receiver. @param _controller Address of the controller @return Address of the fee receiver """ custom_fee_receiver: address = self.fee_receivers[_controller] return custom_fee_receiver if custom_fee_receiver != empty(address) else self.default_fee_receiver ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.fee_receiver( /* _controller: address */ "0x0000000000000000000000000000000000000000", ) ``` :::: ### `set_default_fee_receiver` ::::description[`LendFactory.set_default_fee_receiver(_fee_receiver: address)`] :::guard[Guarded Method by [Snekmate 🐍](https://github.com/pcaversaccio/snekmate)] This function is only callable by the `owner` of the contract. ::: Sets the default fee receiver for all markets that don't have a custom one. | Input | Type | Description | | --- | --- | --- | | `_fee_receiver` | `address` | New default fee receiver address | Emits: `SetFeeReceiver` event. Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @reentrant def set_default_fee_receiver(_fee_receiver: address): """ @notice Set default fee receiver who earns admin fees on all controllers without a custom fee receiver @param _fee_receiver Address of the receiver """ ownable._check_owner() self._set_default_fee_receiver(_fee_receiver) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, signer) const tx = await contract.set_default_fee_receiver( /* _fee_receiver: address */ "0x0000000000000000000000000000000000000000", ) await tx.wait() ``` :::: ### `set_custom_fee_receiver` ::::description[`LendFactory.set_custom_fee_receiver(_controller: address, _fee_receiver: address)`] :::guard[Guarded Method by [Snekmate 🐍](https://github.com/pcaversaccio/snekmate)] This function is only callable by the `owner` of the contract. ::: Sets a custom fee receiver for a specific market's controller. | Input | Type | Description | | --- | --- | --- | | `_controller` | `address` | Controller address | | `_fee_receiver` | `address` | Custom fee receiver address | Emits: `CustomSetFeeReceiver` event. Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @reentrant def set_custom_fee_receiver(_controller: address, _fee_receiver: address): """ @notice Set fee receiver who earns admin fees for a specific controller @dev Setting to zero address resets to default fee receiver @param _controller Address of the controller @param _fee_receiver Address of the receiver """ ownable._check_owner() contract_info: ILendFactory.ContractInfo = self.check_contract[_controller] assert contract_info.contract_type == ILendFactory.ContractType.CONTROLLER, "not a controller" self.fee_receivers[_controller] = _fee_receiver log ILendFactory.SetCustomFeeReceiver(controller=_controller, fee_receiver=_fee_receiver) @internal def _set_default_fee_receiver(_fee_receiver: address): assert _fee_receiver != empty(address), "invalid receiver" self.default_fee_receiver = _fee_receiver log ILendFactory.SetFeeReceiver(fee_receiver=_fee_receiver) ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, signer) const tx = await contract.set_custom_fee_receiver( /* _controller: address */ "0x0000000000000000000000000000000000000000", /* _fee_receiver: address */ "0x0000000000000000000000000000000000000000", ) await tx.wait() ``` :::: --- ## Contract Ownership ### `admin` ::::description[`LendFactory.admin() -> address: view`] Returns the current owner of the factory contract. Returns: owner address (`address`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view @reentrant def admin() -> address: """ @notice Get the admin of the factory @dev Called `admin` for backwards compatibility @return Address of the factory admin """ return ownable.owner ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.admin() ``` :::: ### `pause` ::::description[`LendFactory.pause()`] :::guard[Guarded Method by [Snekmate 🐍](https://github.com/pcaversaccio/snekmate)] This function is only callable by the `owner` of the contract. ::: Pauses the factory, preventing new market creation. Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external def pause(): """ @notice Pause new market creation """ ownable._check_owner() pausable._pause() ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, signer) const tx = await contract.pause() await tx.wait() ``` :::: ### `unpause` ::::description[`LendFactory.unpause()`] :::guard[Guarded Method by [Snekmate 🐍](https://github.com/pcaversaccio/snekmate)] This function is only callable by the `owner` of the contract. ::: Unpauses the factory, re-enabling market creation. Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external def unpause(): """ @notice Unpause the factory to allow new market creation """ ownable._check_owner() pausable._unpause() ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, signer) const tx = await contract.unpause() await tx.wait() ``` :::: --- ## Other Methods ### `version` ::::description[`LendFactory.version() -> String[5]: view`] Returns the contract version string. Returns: version (`String[5]`). Excerpt from [`lending/LendFactory.vy` at `0d726b1`](https://github.com/curvefi/curve-stablecoin/blob/0d726b110555e9506f5bec7e4b04eaac7b2a7986/curve_stablecoin/lending/LendFactory.vy): ```vyper @external @view def version() -> String[5]: return c.__version__ ``` ```ts const contract = new Contract('0x8f6B56EC5ddF1F2691a1059f1D3cd97Ac9EaB0bd', LendFactoryAbi, provider) const result = await contract.version() ``` ::::