# x402 beside a seller's stack > Serve an x402 resource with your own server and facilitator, and the seller door for the ATR and the check. Source: https://connectors.integraledger.com/guides/x402 This guide serves an x402 resource from your own server, with your own facilitator, and uses the seller door for the ATR and the check. The pairing is `x402/exact/eip155/eip3009`: H is the `nonce` of the EIP-3009 authorization the payer signs. ```mermaid sequenceDiagram participant B as Buyer's agent participant R as Your resource server participant D as Seller door participant F as Your facilitator B->>R: GET /v1/report R->>D: issue (accepts, request, content) D-->>R: atrHash, link, carriers R-->>B: 402 PaymentRequired with extensions.legalContext B->>R: GET /v1/report with PAYMENT-SIGNATURE R->>D: claim (payment, chosen = accepted) D-->>R: settling R->>F: verify, settle F-->>R: transaction R->>D: report (reference = transaction) R-->>B: 200 and the resource ``` ## What each call sends | Call | Field | Value | | -------- | ----------------- | -------------------------------------------------------------------------------------------------------- | | `issue` | `offers` | Each `PaymentRequirements` exactly as the 402 will carry it, with `pairing` `x402/exact/eip155/eip3009`. | | | `request` | The commitment to the request the 402 answers. | | | `lifetimeSeconds` | The largest `maxTimeoutSeconds`. | | `claim` | `payment` | The `PaymentPayload`, exactly as received. | | | `chosen` | Its `accepted`. | | | `network` | `accepted.network`. | | | `request` | The same commitment. | | | `settleBy` | The authorization's `validBefore`. | | `report` | `reference` | The facilitator's `transaction`. | | | `chosen` | `accepted`, when the payment was not claimed. | ## The whole flow This program issues the ATR, builds the 402 with the LCP package's x402 entry point, and claims the payment the buyer presents. The door is the stand-in (see [Getting started](https://connectors.integraledger.com/getting-started)), so the buyer's payment is vector `CV6`'s. Your facilitator would verify and settle between the claim and the report. ```ts title="x402.ts" import type { ClaimResponse, IssueRequest, IssueResponse, Refusal } from "@integraledger/agentic-connectors"; import { VECTORS } from "@integraledger/agentic-connectors"; import { exactEip3009, type PaymentRequired, type PaymentRequirements } from "@integraledger/lcp/x402"; const door = process.env.SELLER_DOOR_URL ?? "https://seller.example/door"; const credential = process.env.SELLER_CREDENTIAL ?? ""; async function call(path: string, body: unknown): Promise { const res = await fetch(`${door}${path}`, { method: "POST", headers: { authorization: `Bearer ${credential}`, "content-type": "application/json" }, body: JSON.stringify(body), }); const answer = (await res.json()) as T | Refusal; if (!res.ok) throw new Error(`${path}: ${res.status} ${(answer as Refusal).code}`); return answer as T; } const option: PaymentRequirements = { scheme: "exact", network: "eip155:84532", amount: "10000", asset: "0x036CbD53842c5426634e7929541eC2318f3dCF7e", payTo: "0x209693Bc6afc0C5328bA36FaF03C514EF312287C", maxTimeoutSeconds: 60, extra: { name: "USDC", version: "2" }, }; const request = { method: "GET", path: "/v1/report", query: "", bodyDigest: "0xe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855", } as const; // 1. Issue the ATR before the 402 goes out. const issueBody: IssueRequest = { mintRequestId: "chk_7Q2:v1", resource: "quote", lifetimeSeconds: option.maxTimeoutSeconds, offers: [{ pairing: "x402/exact/eip155/eip3009", option }], request, content: [{ slot: "terms", bytes: Buffer.from('"Pay 10000 base units of USDC for one report."').toString("base64") }], }; const issued = await call("/issue", issueBody); // 2. Place H and the link in the 402, through the LCP package's entry point for the pairing. const challenge: PaymentRequired = { x402Version: 2, resource: { url: "https://api.seller.example/v1/report" }, accepts: [option], }; const advertised = exactEip3009.advertise(challenge, issued.atrHash, issued.link, option); if ("refused" in advertised) throw new Error(advertised.code); const info = advertised.extensions?.["legalContext"]?.info; console.log("402 carries H:", JSON.stringify(info) === JSON.stringify(issued.carriers.legalContext)); // 3. The buyer pays. Claim the payment before the facilitator sees it. const payment = (VECTORS["CV6"]!.steps[1]!.request.body as { payment: { accepted: PaymentRequirements } }).payment; const validBefore = (payment as unknown as { payload: { authorization: { validBefore: string } } }).payload.authorization.validBefore; const claimed = await call("/claim", { resource: "quote", pairing: "x402/exact/eip155/eip3009", payment, chosen: payment.accepted, network: payment.accepted.network, request, settleBy: Number(validBefore), }); console.log("claim:", claimed.state, "claimed:", claimed.proves.claimed); // 4. Verify and settle with your facilitator, then report its `transaction` to the door. ``` ```text output 402 carries H: true claim: settling claimed: true ``` After your facilitator settles, report `{atrHash, pairing, outcome: "paid", reference: , network}` (see [the `report` operation](https://connectors.integraledger.com/guides/report)). ## Where H is on chain The facilitator submits the payer's authorization to the token contract, which verifies the signature when it executes the transfer. H is then on chain as the `nonce` topic of the contract's `AuthorizationUsed` event in the settlement transaction. Anyone holding the ATR can hash it and find that event; the chain alone does not reveal the ATR's content. ## Other x402 pairings Every x402 pairing uses the same calls; what differs is where H rides and what the record proves. The [pairings reference](https://connectors.integraledger.com/reference/pairings) lists them, and the LCP package's documentation at [lcp.integraledger.com](https://lcp.integraledger.com) describes each binding. For Tron and Polkadot, the [profile facilitator](https://connectors.integraledger.com/guides/facilitator) is a facilitator you can run.