> For the complete documentation index, see [llms.txt](https://docs.kpk.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.kpk.io/funds/infrastructure/onchain-accounting/price-feeds/sdai.md).

# sDAI

Custom price feed for Sky Savings Dai (sDAI).

Custom price feed for **Sky Savings Dai (sDAI)**. sDAI is an ERC-4626 vault share that accrues value as savings yield accumulates. The price is derived from the vault's current share-to-asset conversion rate multiplied by the NAV's DAI/USD price.

**Source:** [`sDAI_CustomPriceFeed.sol`](https://github.com/karpatkey/onchain-accounting/blob/main/src/prices/protocols/sDAI_CustomPriceFeed.sol)

***

## Approach

`sDAI.convertToAssets(1 sDAI)` × DAI/USD (from the NAV's primary feed)

{% hint style="info" %}
The DAI/USD term is sourced from the NAV's own selector — see [Base/USD from the NAV's own selector](/funds/infrastructure/onchain-accounting/price-feeds.md#base-usd-from-the-navs-own-selector).
{% endhint %}

{% hint style="info" %}
**sDAI is a Sky contract, not a Spark one**, despite arriving alongside the Spark Savings feeds — Spark ships no Savings DAI vault, and sDAI is the genuine DAI savings vault (it was Spark's savings-DAI product before the USDS rebrand). DeBank still files it under the `spark` protocol.
{% endhint %}

***

## Price calculation

```
decimals = sDAI.decimals()                     // vault share decimals
rate     = sDAI.convertToAssets(10^decimals)   // DAI per 1 sDAI
price    = rate × DAI_USD / 10^assetDecimals
```

| Input               | Source                                             | Description                                              |
| ------------------- | -------------------------------------------------- | -------------------------------------------------------- |
| `convertToAssets()` | `IERC4626(sDAI)`                                   | DAI backing per 1 sDAI share at the current accrued rate |
| `DAI_USD`           | NAV base — `getPriceDataNoDivergence(DAI)` (8 dec) | the NAV's primary DAI/USD price                          |

The divisor is `10^assetDecimals` (the **underlying's** decimals), not the share decimals — they differ whenever a vault uses a decimals offset. Result carries the feed's **8 decimals**.

***

## Constructor

```solidity
constructor(
    address vault_,
    address nav_,
    address baseAsset_
)
```

| Parameter    | Description                                                                                                                           |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------- |
| `vault_`     | The sDAI vault address (also used to read vault decimals)                                                                             |
| `nav_`       | NAVCalculator (proxy) — supplies the base asset's USD price via `getPriceDataNoDivergence`                                            |
| `baseAsset_` | The registered base asset whose USD price is read (DAI); **must equal the vault's `asset()`** — reverts `BaseAssetMismatch` otherwise |

***

## Staleness

The price is stale if the NAV reports the base asset (DAI) stale — all its feeds stale. The base leg's `updatedAt` comes from the NAV's selected DAI feed. The `convertToAssets` rate has no heartbeat — it is a live view on the ERC-4626 vault.

***

## Chains

Deployed on **Ethereum mainnet**. Gnosis prices its own savings-DAI via [sXDAI](/funds/infrastructure/onchain-accounting/price-feeds/sxdai.md), a separate feed.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.kpk.io/funds/infrastructure/onchain-accounting/price-feeds/sdai.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.