All projects on Base Sepolia matching “verification”

Buy one virtual number for SMS verification. First GET /agent/v1/quote, then POST here with X-Quote-Id and Idempotency-Key (service_id/country_id in the query string). The 402 advertises the locked price. If no number is available the API answers 409 no_numbers and nothing is charged.

Domain-level contact preflight with MX provider, SPF, DMARC and structured risk signals. Does not claim mailbox existence.