goldprice.devPricing: two different entry bets
For GoldAPI.io, its plan listing shows Unlimited at $99/month. Compare each provider's pricing page for current plans.
Both bill overage automatically rather than throttling requests. Neither publishes a hard cutoff, so a traffic spike shows up as a bill rather than a blocked call on either service.
Coverage: full catalog against a gold-and-silver focus
Metals-API's catalog reaches into industrial metals, aluminum, nickel, zinc, and more, on the same key that serves gold. GoldAPI.io's own comparison page shows copper marked as unsupported, and neither provider's page documents a wider industrial lineup for GoldAPI.io.
Both list silver spot and futures at parity with gold. Currency coverage differs: Metals-API states 170+, GoldAPI.io states 72. Neither difference is likely to be the deciding factor unless a specific currency is a hard requirement.
Where the numbers come from
GoldAPI.io states it holds LBMA AM/PM fix redistribution rights, giving it a named benchmark tie to point to. Metals-API's page makes no equivalent claim about a specific fixing source. GoldAPI.io also states LBMA AM fix history since 1968; Metals-API's page doesn't state an equivalent figure for its own history.
Developer experience
Metals-API states its endpoint shape follows the Fixer.io convention, which matters if a team is migrating off Fixer and wants to avoid rewriting request logic. GoldAPI.io's page makes no equivalent shape claim. Both list their TypeScript and Python SDKs as community-maintained rather than first-party, so either choice means budgeting extra review time for the wrapper library itself.