Call before paying an unfamiliar x402 endpoint to check that it is real and actually gets paid. Pass ?url=<endpoint URL>. ProvenPaid probes the endpoint without paying, validates its x402 challenge (v1/v2; MPP detected) and reads public Base data for its receiving address: distinct payers, repeat-payer share, payer concentration and coverage, each with source and timestamp. Evidence, not a verdict. Not charged for invalid or unsafe URLs.