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CURB

Dual-payee x402

A match payment is not a single transfer. The 402 challenge lists two accepts:

  1. Seller — USDC to sellerPayTo for the matched slice
  2. Hub — protocol fee to HUB_PAY_TO (bps + floor)

Settlement is x402 USDC on both Base and Solana. Each swap clears seller + protocol fee.

Rails

  • USDC on Base (eip155:8453) via x402
  • USDC on Solana (SPL via x402)

(Buyers may also pay via pay.sh on Solana — buyer-side CLI, not a seller acceptor.)

Buyers (or their wallets / facilitators / clients) must satisfy the challenge before the hub marks the match paid and issues a grant.

Why dual: seller gets paid for capacity; protocol fee funds the rail without the hub custodying inference keys or proxying token streams.

See also: Fees, Pay a match.