> ## Documentation Index
> Fetch the complete documentation index at: https://docs.4mica.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Facilitator URLs

> Understand when seller middleware uses the facilitator.

You use the facilitator from server-side middleware. Buyers usually should not call a hosted facilitator URL directly. They call your API, receive HTTP 402, sign a guarantee, and retry your protected route.

That distinction matters because you own the commercial context: route, price, accepted networks, accepted assets, `payTo` address, logging, and abuse policy.

## URLs your service uses

| URL type            | Who calls it                                | Purpose                                                    |
| ------------------- | ------------------------------------------- | ---------------------------------------------------------- |
| Protected route     | Buyer or buyer agent                        | Requests the paid resource.                                |
| Facilitator API     | Your middleware                             | Verifies and settles signed payment guarantees.            |
| Core4Mica contracts | Payer or seller through protocol operations | Collateral, settlement, claim, and withdrawal enforcement. |

## Keep facilitator calls server-side

Server-side facilitator calls let you:

* apply allowlists, blocklists, and rate limits;
* attach request metadata for support and audit;
* hide infrastructure details from buyers;
* migrate facilitator deployments without changing your protected routes.

## Hosted facilitator

Hosted deployments commonly use:

```txt theme={null}
https://x402.4mica.xyz/
```

Use hosted or self-hosted facilitator URLs from your server configuration. Do not make buyers depend on those URLs directly unless you are intentionally exposing a lower-level integration.

## Operational guidance

* Log every verification and settlement request with route, buyer, network, price, guarantee ID, and response.
* Reject guarantees for routes, prices, assets, or networks you no longer accept.
* Treat unexpected direct facilitator usage as an integration smell unless you explicitly documented it.