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

# Machine Payments Protocol for X API

> Use HTTP 402 and Tempo USDC for anonymous fixed-price tweet, user, follower, trend, Radar, health, and pricing requests.

<blockquote className="agent-llms-directive">
  For the complete documentation index, see <a href="/llms.txt">llms.txt</a>.
</blockquote>

The [Machine Payments Protocol](https://mpp.dev) (MPP) is an open standard for machine-to-machine payments over HTTP. Xquik accepts direct MPP payments on 7 fixed-price read operations. You can call them without an account, API key, or subscription.

## How it works

MPP uses HTTP 402 (Payment Required) as a payment challenge. When you call a direct MPP operation without authentication, the server returns an `application/problem+json` response and a `WWW-Authenticate: Payment` header. Your client pays through Tempo (USDC), then retries the request with a payment credential.

```text theme={null}
Client                              Xquik
  │                                   │
  │  1. GET /api/v1/x/tweets/123      │
  │──────────────────────────────────▶│
  │                                   │
  │  2. 402 Payment Required          │
  │     WWW-Authenticate: Payment     │
  │     (challenge with amount, etc.) │
  │◀──────────────────────────────────│
  │                                   │
  │  3. Pay via Tempo (USDC)          │
  │           (off-band)              │
  │                                   │
  │  4. Retry with credential         │
  │  Authorization: Payment proof     │
  │──────────────────────────────────▶│
  │                                   │
  │  5. HTTP response +               │
  │     Payment-Receipt               │
  │◀──────────────────────────────────│
```

<Note>
  Every response after an accepted payment includes `Payment-Receipt`, including non-2xx responses. The receipt confirms settlement, not application success. Challenges and rejected payment credentials do not include a receipt.
</Note>

The same `402` body also advertises an optional accountless guest wallet. The MPP challenge remains unchanged. A failed read creates no checkout. Create a guest Stripe Payment Link only after the user confirms an amount.

No account, API key, or subscription is required. The payment credential authenticates the retried request.

## Payment method

MPP payments on Xquik use **Tempo** with USDC, a dollar-pegged stablecoin. Tempo provides the settlement method for these fixed charges.

You need a funded Tempo USDC wallet. See the [MPP quickstart](/mpp/quickstart) for setup instructions.

## Discovery

MPP discovery metadata is available at:

```text theme={null}
https://xquik.com/.well-known/mpp.json
```

The document points clients to the live OpenAPI spec and MPP overview page.

## Payment intent

All direct MPP operations use the `charge` intent. Each accepted payment settles the fixed price for one request. Xquik does not advertise direct MPP session pricing for result-sized pages.

## Eligible endpoints

| Endpoint                          | Method | Price                | Intent |
| --------------------------------- | ------ | -------------------- | ------ |
| `/api/v1/x/tweets/{id}`           | GET    | USD 0.00015 per call | charge |
| `/api/v1/x/users/{id}`            | GET    | USD 0.00015 per call | charge |
| `/api/v1/x/followers/check`       | GET    | USD 0.00075 per call | charge |
| `/api/v1/x/articles/{tweetId}`    | GET    | USD 0.00075 per call | charge |
| `/api/v1/trends`                  | GET    | USD 0.00045 per call | charge |
| `/api/v1/x/trends`                | GET    | USD 0.00045 per call | charge |
| `/api/v1/x/communities/{id}/info` | GET    | USD 0.00015 per call | charge |

An accountless guest wallet covers 33 prepaid GET routes, including these 7. See the [guest paid-read route inventory](/guides/guest-wallets#eligible-paid-read-routes). Direct MPP payment credentials and guest keys cannot access monitors, webhooks, extractions, draws, writes, account routes, or account credential routes. API MCP cannot execute guest wallet credential routes.

## MPP vs subscription

|                                                | MPP                            | Guest wallet                            | Account                                              |
| ---------------------------------------------- | ------------------------------ | --------------------------------------- | ---------------------------------------------------- |
| **Account required**                           | No                             | No                                      | Yes                                                  |
| **Credential**                                 | Per-request payment credential | `paid_reads` API key                    | Full API key or OAuth token                          |
| **Payment**                                    | Per request via Tempo (USDC)   | $10-$250 USD Stripe-hosted Payment Link | Available account credits; plans add monthly credits |
| **Available endpoints**                        | 7 fixed-price GET operations   | 33 prepaid GET routes                   | Full account API                                     |
| **Write actions**                              | Not available                  | Not available                           | Available with a connected X account                 |
| **Monitors, webhooks, extractions, and draws** | Not available                  | Not available                           | Available                                            |
| **Best for**                                   | Machine-paid requests          | Prepaid reads without an account        | Full platform workflows                              |

## Next steps

<CardGroup cols={2}>
  <Card title="MPP quickstart" icon="rocket" href="/mpp/quickstart">
    Make your first pay-per-use API call.
  </Card>

  <Card title="Authentication" icon="key" href="/api-reference/authentication">
    All authentication methods including MPP headers.
  </Card>

  <Card title="Billing & usage" icon="credit-card" href="/guides/billing">
    Subscription, guest wallet, and direct MPP pricing.
  </Card>

  <Card title="Guest wallets" icon="wallet-cards" href="/guides/guest-wallets">
    Prepay 33 accountless reads with one scoped API key.
  </Card>
</CardGroup>