> For the complete documentation index, see [llms.txt](https://docs.primestaking.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.primestaking.xyz/products/xdc-liquid-staking/psxdc-rate-oracle.md).

# psXDC Rate Oracle (integrators)

For money markets and other integrators that want to price **bridged psXDC** on Base, Arbitrum, or BNB Chain. psXDC is a yield-bearing vault share: its fair value is `XDC price × psXDC/XDC exchange rate`. This oracle publishes that exchange rate cross-chain from XDC so you can price psXDC exactly like a wstETH/rETH rate provider.

## Interface

`PsxdcRateOracle` implements the Chainlink `AggregatorV3Interface`:

```solidity
function decimals() external view returns (uint8);        // 18
function latestRoundData() external view returns (
    uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound
);
function isStale() external view returns (bool);          // true past the staleness window
```

`answer` = XDC redeemable per **1e18** psXDC (18 decimals). Compose it with your existing XDC/USD feed:

```
psXDC/USD = latestRoundData().answer * (XDC/USD) / 1e18
```

## Safety guarantees

The rate can only be written by the wired XDC publisher (LayerZero peer auth, 2 required DVNs). Each update is additionally guarded on the destination:

* **Monotonic** — the rate cannot decrease (share price only grows). A rare validator-loss writedown requires an explicit, one-shot owner override, so a spurious downward push is rejected by default.
* **Step-capped** — each update may rise by at most `maxStepBps` (default 1%), blunting a bad or manipulated push.
* **Staleness** — `updatedAt` plus `isStale()` let you reject data older than the configured window (default 2 days). PrimeStaking pushes the rate at least daily, and the push is permissionless so it cannot be censored.

If pushes lapse long enough that legitimate cumulative growth would exceed the per-update step cap, the bridged update is rejected and the feed goes stale (safe: integrators see `isStale()` and pause) rather than jumping. The owner restores liveness with a break-glass `adminSetRate`, which still enforces non-zero and (unless explicitly armed) monotonicity — so it can never silently mark psXDC down.

## Recommended usage

Treat the oracle as the **exchange-rate** leg only; keep your own market XDC/USD feed for the base asset. For collateral, apply your standard loan-to-value and liquidation parameters to the composed psXDC/USD price, and reject updates when `isStale()` is true.

## Addresses

Per-chain oracle addresses are in [Deployed Contracts & Addresses](/products/contract-addresses.md). Reach out at <admin@primenumbers.xyz> for listing support.