@glideco/price-feed

Server-authoritative USD price feed for Glide.

Stablecoin shortcut list (USDC, USDT, USDP, DAI, PYUSD, FDUSD, USDe, GHO, TUSD) returns 1:1 with no HTTP. Non-stable assets (ETH, SOL, MATIC, WBTC, LINK, AAVE, UNI, ARB, OP, AVAX, BNB, BTC) hit Coingecko's free tier with a 60s in-memory cache.

import { lookupUsdCents } from '@glideco/price-feed';

const result = await lookupUsdCents({
  asset: 'ETH',
  amountRaw: 1_000_000_000_000_000_000n, // 1 ETH in wei
  decimals: 18,
});

if (result.ok) {
  console.log(`USD cents: ${result.usdCents}`);
} else {
  // 'unsupported' | 'feed_unavailable'
  console.warn('Pending USD valuation', result.reason);
}

Bigint-safe conversion

Raw → USD-cents conversion uses BigInt arithmetic to avoid IEEE-754 precision loss above 2^53 (1 ETH = 1e18 wei sits exactly on the safe boundary). The conversion is:

cents = round(amountRaw * usdPerToken * 100 / 10^decimals)

with usdPerToken scaled to 6-decimal integer precision before the BigInt math.

Vercel cold-start caveat

The cache is process-local. On Vercel serverless, every invocation may land on a cold function instance with an empty cache. Steady-state warm containers get reasonable hits; burst load right after a cold start hammers Coingecko. Mitigation: stablecoins (the dominant send asset) shortcut the fetch entirely, so the worst-case behavior on Coingecko 429 is correct-but-pending audit rows, not silent $0.00.

For high-traffic deployments, swap the in-memory Map for an Upstash Redis-backed cache (planned: cacheGetSet).

License

MIT