> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aifinpay.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Paying a paywalled site

> Discover the route, check client compatibility, and understand prepaid batches and receipt scope.

A site integrated with `@aifinpay/gate` returns HTTP **402** with
`protocol: "AIFP-1"`. One on-chain settlement buys a batch of billing units;
subsequent covered requests use an `AIFP-Receipt` header and consume quota.

## Check the client before paying

* `@aifinpay/mcp` 2.2.x pays with `payable_fetch` once the owner enables it.
* `@aifinpay/agent` 2.1.x pays with `fetchPaid` (v14 journal, gas cap and an
  independent POL/USD rate you supply).
* Both settle AIFP-1 on Polygon splitter v1.4 in native POL and do not execute a
  legacy v1.2 quote. The Python SDK does not pay yet.
* `agent.pay` and AIFP-1 `fetchPaid` are different protocol paths; one is not
  a fallback for a rejected deployment in the other.

If the merchant offers an incompatible route, stop before signing. Installing
[the skill](/skills) provides instructions, not a different executor. Consult
the installed package's documentation for its exact configuration requirements.

## Discover the resource

Read `/.well-known/x402.json` on the **same origin** as the target site. Use
its paths, prices and scopes, then read the site's API catalog for required
parameters. Request the chosen route and inspect the 402 minimum batch.
A fresh quote supplies chain, asset, amount, merchant and expiry.

For example, `dev.ratersapp.com` publishes both discovery and `/api/agent`.
Its `/api/agent/genres` was priced at $0.0005 per standard request with an
exact scope and a $0.10 minimum batch, settling on Polygon v1.4.

## Receipt scope

| Scope | Covers |
| - | - |
| `exact` | The quoted resource path |
| `prefix` | The quoted path and covered descendants |
| `merchant` | Resources covered by that merchant-wide receipt |

Read the scope offered by the merchant. Do not assume that buying one endpoint
opens the whole site or that a client can widen a scope unilaterally.

## Verify the result

A complete supported flow is: quote → approved on-chain settlement → verified
receipt → HTTP 200 data → another covered request using the same receipt.
The second request must consume quota without creating another transaction.
Match the payment transaction with the merchant dashboard's record.

Network gas is separate from the batch price and varies. Keep receipts private:
they are bearer credentials for prepaid access. On a timeout after broadcast,
recover the existing transaction and receipt before considering any new payment.