# Machine payments

> Paying per call over HTTP 402 with the Machine Payments Protocol. Built, and switched off today.

Source: https://storeware.ai/docs/agents/mpp

**Machine payments are switched off.** Nothing on this page can be paid for today. It says what is built, and how to tell when that changes.

The [Machine Payments Protocol](https://paymentauth.org) (MPP) lets an agent pay for a call over HTTP with no checkout page and no account: the server answers `402` with a payment challenge, and the agent pays it and calls again.

## What is built

| Call | What it sells | Seller |
| --- | --- | --- |
| `POST https://api.storeware.ai/api/mpp/enrich` | Product enrichment, from storeware.ai | The platform |
| `POST https://api.storeware.ai/api/mpp/checkout-sessions/{id}/complete` | Completing a shop's checkout session | The shop, on its own Stripe account |

Both are built to take a card, as a Stripe shared payment token. Paying a stablecoin on Tempo is built as well, and is switched off separately.

## What is live today

None of it:

- Both routes answer a well-formed request with `503` and ask for no payment. A malformed one is refused first, with `400` or `422`, as it would be when payment is on.
- [`https://api.storeware.ai/openapi.json`](https://api.storeware.ai/openapi.json), the document that would list what is for sale and how to pay for it, answers `404`. `https://storeware.ai/openapi.json` redirects there.
- No shop lists an MPP offer in its `llms.txt`, its API catalog or its other discovery documents.
- storeware.ai's `llms.txt`, API catalog and agent skills index name no paid call.

The rule behind that: a discovery document never offers a payment the route would refuse.

## How to tell when it changes

Ask for `https://api.storeware.ai/openapi.json`. While it answers `404`, nothing is for sale. Once it answers with a document, that document lists each call that takes payment, what it costs, and each way to pay, and it is the only place to read a price from.

To pay a shop today, use its [UCP or ACP](https://storeware.ai/docs/agents/ucp-acp) checkout, or [x402](https://storeware.ai/docs/agents/x402) where the shop has turned it on.