Build
Credits & billing
A credit is not a call. The debit is proportional to the real per-call cost of the source.
One credit is worth $0.001. Sources cost different amounts, and the debit reflects that: a token.price call debits 1 credit, a social.value call debits 5 credits, because a paid social source really does cost more to serve. The debit is proportional to the real per-call cost, marked up, rounded up so it never falls below cost.
verification.cost: the engine internal charged amount for the decision, a fixed-4 string (for example "1.0000"). Informational. Do not bill on it.
debitedCredits: the credits actually deducted from your balance (for example 5). This is your bill. Integrate against debitedCredits only.
Billing happens on delivery. A call that fails verification, returns empty, times out, or is refused below your level is not charged. Metera bears that cost. Refusals (409) and no_source cost nothing.
Two rails: a credit balance (top up, spend per call) and, on the x402 track, pay-per-call in USDC on Solana with no account. Rate limits are per plan, enforced in code today. Free is 10 requests per minute with a starting credit grant. Paid plans raise the limit (Pro 60 per minute). Only limits actually applied in code are stated here.