> 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/cbeth-l2.md).

# cbETH (L2)

Custom price feed for **Coinbase Wrapped Staked ETH** on L2 chains. No direct cbETH/USD feed exists, so the price is composed from a Chainlink cbETH/ETH feed and an ETH/USD price read from the NAV's own primary feed.

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

**Source:** [`cbETH_L2_CustomPriceFeed.sol`](https://github.com/karpatkey/onchain-accounting/blob/main/src/prices/protocols/cbETH_L2_CustomPriceFeed.sol)

{% hint style="info" %}
**L2 feed.** For the Ethereum mainnet feed, see [cbETH](/funds/infrastructure/onchain-accounting/price-feeds/cbeth.md).
{% endhint %}

***

## Approach

Chainlink cbETH/ETH × NAV-selected ETH/USD

<figure><img src="/files/9CamqJ8SrcVNeZzVJ9qI" alt="Left-to-right flowchart of the cbETH (L2) price feed: rate and Chainlink inputs combine into a USD price, with a staleness gate."><figcaption><p>cbETH (L2) price feed — how its oracle inputs compose into a USD price, with the staleness gate.</p></figcaption></figure>

***

## Price calculation

```
price = (cbETH/ETH) × (ETH/USD) / 10^(cbETH/ETH decimals)
```

| Input       | Source                                              | Description                      |
| ----------- | --------------------------------------------------- | -------------------------------- |
| `cbETH/ETH` | Chainlink cbETH/ETH feed (`latestRoundData`)        | cbETH price in ETH (18 dec)      |
| `ETH/USD`   | NAV base — `getPriceDataNoDivergence(WETH)` (8 dec) | the NAV's primary WETH/USD price |

The cbETH/ETH leg is a Chainlink feed; the ETH/USD leg is the NAV's primary WETH/USD. The divisor is `10 ** RATE_FEED.decimals()`, captured once at construction as `_rateUnit`. Output is **8 decimals** (inherited from the ETH/USD leg).

***

## Constructor

```solidity
constructor(
    address cbEth_,
    address cbEthToEthChainlink_,
    uint256 cbEthToEthHeartbeat_,
    address nav_,
    address baseAsset_
)
```

| Parameter              | Description                                                                                |
| ---------------------- | ------------------------------------------------------------------------------------------ |
| `cbEth_`               | cbETH token address (the supported underlying asset)                                       |
| `cbEthToEthChainlink_` | Chainlink cbETH/ETH aggregator                                                             |
| `cbEthToEthHeartbeat_` | Staleness window (seconds) for the cbETH/ETH feed                                          |
| `nav_`                 | NAVCalculator (proxy) — supplies the base asset's USD price via `getPriceDataNoDivergence` |
| `baseAsset_`           | The registered base asset whose USD price is read (WETH)                                   |

***

## Staleness

`getLatestPrice()` returns `stale = true` if the cbETH/ETH feed satisfies `block.timestamp − updatedAt ≥ heartbeat`, if the cbETH/ETH answer is `≤ 0`, if its `updatedAt` is in the future (clamped to `block.timestamp`), or if the NAV reports the base asset (WETH) stale — all its feeds stale. The base leg's `updatedAt` comes from the NAV's selected WETH feed. The reported `updatedAt` is the **older** of the two legs.

***

## Chains

Deployed on **Base**. The Ethereum mainnet counterpart is [cbETH (Mainnet)](/funds/infrastructure/onchain-accounting/price-feeds/cbeth.md), which uses a rate provider against ETH/USD.


---

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