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

# Payment Model

> Public explanation of how paid and unpaid gateway routes work without exposing gateway internals.

# Payment Model

The gateway uses a simple public boundary:

1. The client requests a route.
2. If the route is paid and no valid proof is attached, the gateway returns `HTTP 402`.
3. The client retries with a valid `x-payment` proof.
4. The gateway forwards the request and returns the upstream result.

## Public payment facts

* networks: Base (always on), plus Polygon and Arbitrum when the facilitator supports them, see [Multi-chain Settlement](/guides/multichain)
* asset: USDC (on-chain rail) or EUR via SEPA Direct Debit (bank rail)
* challenge transport: `HTTP 402 Payment Required`: the challenge lists one `accepts` entry per configured network, with Base always included as a fallback
* proof transport: `x-payment`
* platform fee on USDC rail: **2%** (publishers receive 98% of each settled call)
* platform fee on SEPA rail: none: Apiosk charges a monthly subscription instead of a per-transaction percentage
* settlement contract on Base: [`0x512c770Ef7B651298cBFA2Ab865A81C12F0c703d`](https://basescan.org/address/0x512c770Ef7B651298cBFA2Ab865A81C12F0c703d)

## Payment modes you can use

### Managed wallet mode

A managed agent wallet plus a connect string lets the gateway handle recurring paid calls within configured limits, without you building a payer loop.

<Warning>
  Creating a new managed (custodial) wallet is currently unavailable. The legacy dashboard service that derived and encrypted wallet keys has been retired, so wallet creation returns `custodial_wallet_creation_unavailable`. Managed wallets that already exist keep working, and connect tokens can still be minted for them. For a self-serve wallet today, use the local stdio MCP package and create a local wallet, or bring your own payer with raw x402 mode.
</Warning>

### Raw x402 mode

Use your own payer and sign the challenge yourself. This is the cleanest option when you want direct control over the payment proof flow. The `402` challenge may offer several networks, pick the entry you can pay on and name that network in your payment payload; see [Multi-chain Settlement](/guides/multichain).

### SEPA Direct Debit rail

For EU operators who need bank-side settlement instead of on-chain USDC, the gateway supports SEPA Direct Debit via Mollie. Paid calls are debited from the buyer's IBAN under a mandate signed once in the buyer portal. SEPA is priced as a monthly subscription, not a per-transaction percentage.

You can pin the rail explicitly per request with the `X-Apiosk-Rail` header (`x402`, `sepa`, or `credits`). If you omit it, the gateway selects the cheapest viable rail for the call.

### Unpaid routes

Some endpoints or operations may be configured as unpaid. Those routes do not require a payment proof.

## What is not documented here

This page does not describe settlement topology, operator controls, internal verification behavior, or managed-wallet implementation details beyond the public integration boundary.