pyth

Use the HermesClient from @pythnetwork/hermes-client and call getLatestPriceUpdates with an array of hex feed IDs. The response includes parsed price, confidence, exponent, and publish time, which you convert with price * 10^expo.

Add pyth-solana-receiver-sdk to Cargo.toml and accept a PriceUpdateV2 account in your instruction. Call get_price_no_older_than with the Clock sysvar and a max age in seconds to get a validated price.

Yes, the Hermes client provides getPriceUpdatesStream, which delivers price updates over Server-Sent Events. You subscribe with feed IDs and handle updates in an onmessage callback, closing the EventSource when done.

PriceTooOld occurs when the on-chain price update is older than your max_age_secs parameter. Post a fresh price update in the same transaction before consuming it, or increase the allowed staleness window.

The spot price is the latest aggregate price, while the EMA price is an exponential moving average over roughly one hour weighted by inverse confidence. EMA is recommended for sensitive operations like liquidations to reduce manipulation risk.

The public Hermes endpoint allows about 10 requests per second, 5 concurrent connections, and up to 100 feeds per request. For production workloads, obtain a dedicated endpoint from a Pyth data provider.