# Overview

This overview is written for the **merchant** — the resource server (seller) that integrates the facilitator into its paywall. You never sign the buyer's transfer or interact with the blockchain; the facilitator does the on-chain work. Your job is three calls:

1. **`GET /supported`** once at startup, to learn the fee-payer address and which `(scheme, network)` pairs you can charge on.
2. **`POST /verify`** when a buyer presents a payment, to check it's good _before_ you do any work.
3. **`POST /settle`** to broadcast the payment on-chain and get a transaction signature back.

A buyer hits your protected resource, you reply `402 Payment Required` with your `paymentRequirements`, the buyer signs a transfer and sends it back in an `PAYMENT-SIGNATURE` header. You pass that header into a `paymentPayload`, then call `/verify` and `/settle` with the **same**`(paymentPayload, paymentRequirements)` pair.

```
Solana(blockchain)FacilitatorMerchantBuyerSolana(blockchain)FacilitatorMerchantBuyerAt startupPer paymentGET /supportedkinds + feePayer addressGET /protected-resource402 PAYMENT-REQUIRED + accepts[]Select paymentDetailsfrom accepts[]Create Payment PayloadSign transaction(facilitator set as fee-payer)GET /protected-resourcePAYMENT-SIGNATURE: paymentPayloadPOST /verify(paymentPayload, paymentRequirements)Screen buyer + merchantVerify paymentPayload againstpaymentRequirementsSimulate transactionokVerification ResponseisValid truePerform work to fulfill requestPOST /settle(same payload + requirements)Re-verify + deduplicate settlementsSubmit paymentco-sign as fee-payer + broadcastTransaction signatureWait for blockchain confirmationConfirmedsuccess: true with transaction hash200 OK + protected resourcePAYMENT-RESPONSE paymentResponse
```

## Conventions for all three endpoints:

- Send `Content-Type: application/json` on the two `POST`s.
- A protocol-level rejection (bad payment, sanctioned address, duplicate) is **HTTP 200** with `{ "isValid": false, ... }` or `{ "success": false, ... }`. Only a structurally malformed request body is **HTTP 400**. Don't treat a 200 as success — read the body.
- Pass an `x-request-id` header to correlate logs; if you omit it the facilitator generates one and echoes it back on the response.

## For background on the `solana:…` network identifier and the fee-payer address, see [CAIP-2](https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-2.md) and use the table below:

| Network | CAIP-2 Identifier | Figment Fee Payer |
| --- | --- | --- |
| Solana Mainnet | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp | 93syNmtT1tTd5ZtPwHqzGf6CM7fKhMmArpv4AM4FtyNX |
| Solana Devnet | solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1 | 2bogRi1wDCdT8ECp8aMrZhF4jX23vxZDUxJjaGkcasKg |

Updated 25 days ago