> 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/sxdai.md).

# sXDAI

Custom price feed for **Savings xDAI (sDAI)** on Gnosis Chain. sXDAI is an ERC-4626 vault share that accrues yield from the Gnosis Chain savings rate. The price is derived from the vault's current share-to-xDAI conversion rate multiplied by the xDAI/USD price read from the NAV's own primary feed.

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

{% hint style="info" %}
The xDAI/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 %}

***

## Approach

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

<figure><img src="/files/5dq0hUv51Hiq9DwQzEUy" alt="Left-to-right flowchart of the sXDAI price feed: rate and Chainlink inputs combine into a USD price, with a staleness gate."><figcaption><p>sXDAI price feed — how its oracle inputs compose into a USD price, with the staleness gate.</p></figcaption></figure>

***

## Price calculation

```
decimals = sDAI.decimals()                       // vault share decimals
rate     = sDAI.convertToAssets(10^decimals)     // xDAI per 1 sDAI (vault decimals)
price    = xDAI_USD × rate / 10^decimals
```

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

xDAI on Gnosis Chain is the native gas token, pegged to DAI. The Gnosis savings rate accumulates directly in the sDAI vault, so `convertToAssets` reflects real-time interest accrual. Vault decimals are read once at deploy. Result carries the feed's **8 decimals**.

***

## Constructor

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

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

***

## Staleness

The price is stale if the base USD price is `≤ 0`, or if the NAV reports the base asset (xDAI) stale — all its feeds stale. The base leg's `updatedAt` comes from the NAV's selected xDAI feed. The `convertToAssets` rate has no heartbeat — it is a live view on the ERC-4626 vault.

***

## Chains

Deployed on **Gnosis** only. There is no Ethereum counterpart in this system: mainnet registers `DAI` but not `sDAI`, so no sDAI feed is configured there.


---

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