> ## Documentation Index
> Fetch the complete documentation index at: https://yieldxyz.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Sky

> Deposit USDS, DAI, or USDC into Sky Savings on Ethereum, Base, Arbitrum, Optimism, and Unichain for sUSDS or sDAI.

yield.xyz exposes Sky (formerly MakerDAO) through two distinct mechanisms under one provider. On Ethereum, Sky Savings and Savings Dai are ERC-4626 vaults you deposit into directly. On Base, Arbitrum, Optimism, and Unichain, "Sky Savings Rate" is a swap through Sky's PSM3 contract into a bridged representation of the same share token, not a vault deposit.

## Availability

| Network | Mechanism | Input token | Position token |
| - | - | - | - |
| Ethereum (Sky Savings) | ERC-4626 vault | USDS (or USDC, routed through Sky's PSM) | sUSDS |
| Ethereum (Savings Dai) | ERC-4626 vault | DAI | sDAI |
| Base, Arbitrum, Optimism, Unichain | PSM3 swap | USDC or USDS | sUSDS (bridged representation) |

List the markets enabled for your project with [`GET /v1/yields`](/api-reference/YieldsController_getYields) filtered by `providers=sky`.

## Entering

**Ethereum Sky Savings (sUSDS)** accepts USDS directly, or USDC through Sky's LitePSM: USDC is swapped for USDS first, then deposited, adding an extra approval and swap step ahead of the deposit. `inputToken` is optional; omit it to deposit USDS.

**Ethereum Savings Dai (sDAI)** only accepts DAI; it runs on the generic ERC-4626 path and does not offer a USDC route.

**Base, Arbitrum, Optimism, and Unichain** accept USDC (default) or USDS via `inputToken`, swapped for sUSDS through the network's PSM3 contract with a 0.1% maximum slippage tolerance. This is a swap, not an ERC-4626 deposit.

## Exiting

**Ethereum Sky Savings** declares an optional `outputToken` exit argument: omit it to redeem sUSDS for USDS directly, or set it to USDC to redeem and then swap the USDS through Sky's PSM in the same exit. **Ethereum Savings Dai** does not declare `outputToken` and always redeems to DAI.

**The PSM3 markets** also declare an optional `outputToken`: omit it to swap sUSDS to USDC (the default), or set it to USDS to receive USDS instead.

All four networks settle in a single transaction. There is no cooldown or withdrawal queue anywhere in the Sky integration.

## Rewards and position

Yield is reflected in the share or swap rate, not a growing token balance: sUSDS and sDAI are not rebasing. There is no claim step; reward claiming is automatic everywhere in this integration.

## Next steps

<Columns cols={2}>
  <Card title="Vaults" icon="vault" href="/documentation/earn/defi/vaults/index">
    Compare Sky with the other vault integrations.
  </Card>

  <Card title="Action lifecycle" icon="arrows-rotate" href="/documentation/earn/core-concepts/actions">
    Request, sign, and submit enter and exit actions.
  </Card>
</Columns>


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