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Integrating V3 Vaults

V3 provides all of the same benefits to integrators as V2, but with increased optionality and standardization.

Vaults​

All V3 vaults, whether multi-strategy or single-strategy, are fully ERC-4626 compliant which greatly simplifies and standardizes integrations.

Deposits​

Deposits follow the standard 4626 flow. It is recommended to use deposit over mint when depositing to a Yearn vault.

Example
token.approve(vault, amount)

vault.deposit(amount, receiver)

There is also a 4626 Router available to make multi-step user flows easier.

The max amount that a vault will accept from an address can be returned using the maxDeposit function.

Withdrawals​

The standard 4626 withdrawal functionality works for all V3 vaults, however it is recommended to use redeem instead of withdraw.

Optional Parameters​

V3 Vaults have additional, optional parameters that can be added during withdrawals.

maxLoss​

There is a maxLoss parameter for both withdraw and redeem that is denominated in basis points. This value will enforce the max amount of allowable loss the user will accept during the withdraw and revert if the loss is over that amount.

note
  • redeem Defaults to a maxLoss of 10_000 (100%), meaning it will allow any amount of loss.
  • withdraw Defaults to a maxLoss of 0 (0%), meaning it will not allow any loss.
Example
balance = vault.balanceOf(user)

vault.redeem(balance, receiver, user, maxLoss)
warning

It is recommended to always include maxLoss when possible for the final step in a withdrawal

strategies​

Multi-strategy vaults also have an optional strategies parameter which takes an array (max length of 10) of ordered strategy addresses to withdraw from. This will override the vaults default_queue if the use_default_queue flag is False.

Example
strategies = [compoundLender, aaveLender]

balance = vault.balanceOf(user)

vault.redeem(balance, receiver, user, 1, strategies)

The max amount that a vault will allow an address to redeem/withdraw can be returned using the maxRedeem/maxWithdraw functions. The multi-strategy vaults will also accept the optional parameters corresponding to redeem/withdraw in these max view functions.

Pricing​

Generic pricing of vault tokens can be done using the standard 4626 convertToShares and convertToAssets functions.

While Yearn takes great care to try and prevent manipulation of the conversion functions, it is important to know that are some security considerations if using these functions on chain as part of another protocol. Please read more in Yearn vaults as collateral

V3 vaults also contain the legacy pricePerShare function from the V2 Vaults implementation. However, this is intended as a simple off-chain helper and should not be used for on chain integrations due to precision loss.

Periphery​

There are multiple periphery contracts that can be helpful to get information about Yearn vaults on a specific chain.

Registry​

Retrieve all of the endorsed vaults on a specific chain.

  • getAllEndorsedVaults() Returns a nested array sorted by vaults asset of all endorsed vaults in that registry.
  • getEndorsedVaults(address _asset) Returns and array of all endorsed vaults for that asset
  • vaultInfo(address _vault) Return the Info struct for an endorsed vault that includes its underlying asset, release version, deployment timestamp, vault 'type' (i.e. multi-strategy or single-strategy) and any tag.

Role Manager​

Manages all of the multi-strategy vaults on a chain, and holds the role_manager position for those vaults.

All the other periphery contracts and Yearn multisigs can be retrieved from the Role manager as well using the getter functions, such as getBrain()/getPositionHolder(keccak256("Brain")), getRegistry()/getPositionHolder(keccak256("Registry")), getDebtAllocator(vault), .

Category​

V3 introduces the concept of "categories" for vaults. This is because there will now potentially be multiple multi strategy vaults per underlying asset with the category signalling the difference.

A vault category is appended to the vaults name and symbol that dictates what type of vault it is. For example, 1 vaults are the lowest risk and most similar to the V2 style vaults.

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