goldprice.devPricing: two different entry bets
GoldAPI.io undercuts Metals-API at the entry rung by nearly $25/mo ($4.99 against $29). That gap flips further up the ladder: Metals-API's production tier lands at $99/mo, cheaper than GoldAPI.io's $129/mo. A team that only ever needs a low-volume gold feed pays less on GoldAPI.io; a team that scales into a production workload pays less on Metals-API.
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 sits close: Metals-API states 170+, GoldAPI.io states 160+. 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 20+ years of historical daily depth; 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.