exact scheme is the default and the one most endpoints should use. The seller declares a price, the client signs an authorization for that exact amount, and the facilitator refuses to settle anything else.
Wire shape
amount is the exact wire-unit price. The signedAuthEntries in the X-Payment payload must authorize a transfer of that same amount to payTo in asset, or /verify returns amount_mismatch.
Verify and settle
/verify checks the signature, the amount, the destination, and the balance. /settle transfers exactly amount and returns the txHash. There is no partial settlement.
When to use it
- Any endpoint whose cost is deterministic per call.
- Anything charged per-request rather than per-unit-of-work.
- Almost every REST endpoint.
When not to use it
- LLM completions or any pay-per-token workload — use
upto. - Streaming or unbounded outputs where the final size is unknown.
Related
- POST /verify
- POST /settle
- Error & Rejection Codes for
amount_mismatch,insufficient_funds,authorization_expired.