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The facilitator is a hosted service that does the on-chain work for x402: it verifies signed payment payloads, sponsors gas, and submits the settlement transaction to Sui. Sellers point their x402 middleware at it and never touch an RPC node. 
https://facilitator.tentaclepay.com
It implements the standard x402 v2 facilitator interface, so any x402-compatible server library can use it.

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What it does

  • Verifies that a payment payload is well-formed and valid for the stated requirements — signature, amount, recipient, and network.
  • Settles by submitting the transaction to Sui and waiting for finality, then returns the transaction digest.
  • Sponsors gas for every supported Sui coin, so buyers never need to hold SUI.
  • Never custodies funds. Settlement goes directly from the buyer to the seller’s payTo address. The facilitator only relays and pays for execution.

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Endpoints

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GET /
endpoint
Returns service metadata and the list of available endpoints.
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POST /verify
endpoint
Checks a signed payment against payment requirements without settling. Body: { paymentPayload, paymentRequirements }. Returns whether the payment is valid.
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POST /settle
endpoint
Submits a verified payment to Sui and waits for finality. Body: { paymentPayload, paymentRequirements }. Returns the settlement result, including the transaction digest.
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GET /supported
endpoint
Returns the schemes, networks, and tokens the facilitator supports.
In a typical integration you don’t call these directly — the HTTPFacilitatorClient from @x402/core/server does it for you: 
import { HTTPFacilitatorClient } from "@x402/core/server";

const facilitatorClient = new HTTPFacilitatorClient({
  url: "https://facilitator.tentaclepay.com",
});

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Supported networks

The facilitator registers the exact scheme for sui:mainnet and sui:testnet. See Supported networks for the full token list.

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Gas sponsoring on Sui

Gas sponsoring is how the facilitator lets buyers pay without holding SUI — and Sui’s gas model makes it fit the x402 request/response flow exactly. A Sui transaction names a sender and a gas owner separately. For a sponsored payment the buyer is the sender and the facilitator is the gas owner. Sui also supports address-balance sponsorship: the gas owner pays from its address balance instead of pinning specific gas coin objects. In the SDK that’s an empty gas payment — setGasPayment([]) (Mysten docs). Because no gas coin objects are baked into the signed bytes, the buyer signs first and the facilitator co-signs the same bytes afterward — fully asynchronous. There’s no pre-flight round trip to reserve gas, no coin-object equivocation to manage, and no Enoki in the loop. It maps onto x402 one-to-one:
1

Facilitator advertises the sponsor

/supported returns the facilitator’s gasOwner address and gasBudget in the requirements’ extra. The facilitator can rotate across a pool of sponsor addresses to spread load.
2

Buyer builds and signs

The buyer builds a PTB that transfers the payment with 0x2::balance::send_funds, sets itself as the sender, sets the facilitator as the gas owner, and leaves the gas payment empty. It signs the bytes and returns them in the x402 payload — without contacting the facilitator first.
3

Facilitator verifies

/verify checks the PTB shape — asset, amount, recipient, the advertised gas owner, and an empty gas payment — then simulates it on-chain.
4

Facilitator co-signs and settles

/settle signs the same bytes as the sponsor and executes with both signatures, [buyerSignature, sponsorSignature]. Gas is drawn from the facilitator’s address balance.
Sui’s default stablecoins transfer gasless — for those the buyer’s PTB carries a zero gas budget, so there’s nothing to sponsor. For any other supported coin, the facilitator’s address balance covers execution. See Supported networks.

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Self-hosting

The facilitator is open source and built on @tentaclepay/sui-x402. To run your own, register the Sui exact scheme on an x402Facilitator with a FacilitatorSuiSigner — the address that sponsors gas and co-signs transactions: 
import { x402Facilitator } from "@x402/core/facilitator";
import { toFacilitatorSuiSigner } from "@tentaclepay/sui-x402";
import { ExactSuiScheme } from "@tentaclepay/sui-x402/exact/facilitator";

const signer = toFacilitatorSuiSigner({
  address: "0xYourGasSponsorAddress",
  signTransaction: async (bytes) => {
    /* sign with the sponsor keypair */
  },
});

const facilitator = new x402Facilitator();
facilitator.register(["sui:mainnet", "sui:testnet"], new ExactSuiScheme(signer));
Fund the sponsor address’s SUI balance so it can cover gas. Address-balance sponsorship draws from that balance, so you never select or lock individual gas coin objects — and the signer only ever signs bytes the buyer already produced, so it can run statelessly. To spread load, supply a FacilitatorSuiSigner whose getAddresses() returns several sponsor addresses; the scheme picks one per request. Expose /verify, /settle, and /supported over HTTP, and point your sellers’ HTTPFacilitatorClient at your deployment.
Most teams don’t need to self-host. The hosted facilitator at facilitator.tentaclepay.com is free and covers Sui mainnet and testnet.