# FacilitatorClient Charge agents to call your API. Register a resource server, then verify and settle x402 payments against it. ```typescript import { FacilitatorClient } from "@newton-xyz/isaac"; const facilitator = new FacilitatorClient({ baseUrl: "https://api.example.com", operatorApiKey: "nab_sk_...", // manages resource servers serverApiKey: "...", // optional, for the payment flow }); ``` Two keys, two jobs: the **operator key** registers and manages resource servers; the **server key** (issued when you create a server) verifies and settles payments. Set `serverApiKey` once you have it, or create a second client. ## Resource servers ```typescript const { server, apiKey } = await facilitator.createServer({ name: "My API", recipientAddress: "0x...", // where payments land vaultAddress: "0x...", }); const servers = await facilitator.listServers(); // ResourceServer[] const one = await facilitator.getServer(server.id); await facilitator.updateServer(server.id, { rateLimitPerMinute: 120 }); const { apiKey: rotated } = await facilitator.rotateServerKey(server.id); await facilitator.deactivateServer(server.id); ``` `createServer` requires `name`, `recipientAddress`, and `vaultAddress`; everything else defaults server-side. It returns the created `server` and its `apiKey` — store the key, it is not shown again. ## The payment flow These need the `serverApiKey`. ```typescript const v = await facilitator.verify(payload); // { valid, paymentHash, settlementMethod } const s = await facilitator.settle(v.paymentHash); // { status, txHash?, network? } const status = await facilitator.settleStatus(v.paymentHash); const supported = await facilitator.supported(); // networks + tokens ``` `verify` checks a payment authorization and reserves it, returning a `paymentHash`. If the agent's policy queues the payment for approval, `verify` returns `policyStatus: "pending_approval"` with a `pendingIntentId` instead. `settle(paymentHash)` submits the reserved payment for on-chain settlement; poll `settleStatus` for the terminal result. Most integrations don't call `verify`/`settle` directly — they let [createX402Fetch](/reference/sdk/create-x402-fetch) drive the flow from the paying side. Use these methods when you operate the resource server yourself. ## See also * [Meter Your API](/guides/meter-your-api) — the end-to-end resource-server walkthrough. * [createX402Fetch](/reference/sdk/create-x402-fetch) — the paying side of x402.