Explainer · TIER_B
What is a paid API?
An HTTP interface whose unpaid call is a challenge and whose paid call is the documented result.
zFinia published 7 September 2026
A paid API is not a PDF invoice emailed after the fact. The unpaid request is a challenge. The paid retry returns the documented JSON. Price, asset, network and schema are discoverable before money moves.
If the 402 and the listing disagree, the live 402 wins and the listing is wrong.