Fetch and cache a coin price without hammering the API
One request per interval for the whole site, an atomic cache write, and a stale copy served rather than nothing when the feed is down.
Price Feeds
Fetching, caching and sanity-checking coin prices before you pay anyone with them.
4 entries
Take the median of several price feeds
One API returning a wrong number should not decide what you pay. Three sources and a median makes a single bad quote irrelevant.
Refuse to pay on a stale price
The guard that turns a dead price feed into a delayed payout instead of a wrong one. Fail closed, log loudly, retry later.
Keep rewards worth the same in dollars as the coin moves
Store the reward in USD, convert at claim time, and clamp the movement so a price spike cannot empty the faucet in an afternoon.