Payment Model
The gateway uses a simple public boundary:
- The client requests a route.
- If the route is paid and no valid proof is attached, the gateway returns
HTTP 402.
- The client retries with a valid
x-payment proof.
- 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
- 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
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.
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.
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.
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.
