Facilitators

In x402, a facilitator is the role that verifies and settles. A resource server sends it the buyer's payment and the requirements it answered. POST /verify says whether the payment is valid, and POST /settle submits it to its network and answers with the transaction. GET /supported lists the kinds of payment it serves. The seller chooses its facilitator.

Where it sitsCopy Anchor Link

The seller door and the facilitator do different jobs, in this order:

1. claim at the seller door: the payment carries the H issued for this request. Every refusal comes here, before money moves.
2. /verify and /settle at the facilitator: the payment is valid for its requirements, and is submitted.
3. report at the seller door: the facilitator's transaction becomes the record's reference.

The profile facilitatorCopy Anchor Link

x402 specifies neither Tron nor Polkadot. LCP defines one transfer method on each, in which the payer's own signed transaction carries H:

• x402/exact/tron/lcp-trc20-memo: H in a TRC-20 transfer's memo;
• x402/exact/polkadot/lcp-assets-remark: H in a remark batched with an Asset Hub transfer.

@integraledger/profile-facilitator is a facilitator for those two profiles. It holds no key and pays no fee: it checks, submits exactly the bytes the payer signed, deduplicates settlements in Postgres, and reports what the network shows. It checks that the payment carries an LCP sha256 string; which H the seller issued is the seller door's claim to check.

See Run the profile facilitator, and the Tron and Polkadot guides.