---
description: Use x402 to pay for and authenticate your inference requests.
title: Machine Payments (x402)
image: https://developers.cloudflare.com/ai-gateway/features/machine-payments/og.png?v=c0a7655b53b651fc
---

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# Machine Payments (x402)

Last updated Sep 30, 2026|Copy as Markdown| [View as Markdown](https://developers.cloudflare.com/ai-gateway/features/machine-payments/index.md)| [Agent setup](https://developers.cloudflare.com/agent-setup/)

Machine Payments allows clients to pay for inference calls to select open models from their stablecoin wallet, without having to maintain a prepaid credit balance. To use Machine Payments, you must be based in the United States and have a credit card on file.

The `Payment-Method: x402` header tells Cloudflare to negotiate payment through the [x402 protocol ↗︎](https://github.com/x402-foundation/x402). This header is specific to Cloudflare.

## Prerequisites

- Ensure your Cloudflare account has a credit card on file.
- Ensure you have [authenticated](https://developers.cloudflare.com/ai-gateway/configuration/authentication/) your AI Gateway.

## Eligible endpoints

- [POST /ai/run](https://developers.cloudflare.com/ai-gateway/usage/rest-api/#airun-universal-endpoint)

## Eligible models

- `z-ai/glm-4.7-flash`
- `google/gemma-4-26b-a4b-it`
- `openai/gpt-oss-20b`
- `alibaba/qwen3.8-27b`

## Use Machine Payments

Machine Payments works with the Cloudflare API and requires a Cloudflare API token.

### Transaction flow

An x402-compatible client handles the challenge and retry automatically.

1. The client sends an inference request with the Cloudflare-specific `Payment-Method: x402` header. This requests x402 payment instead of using the account's configured billing method.
2. AI Gateway validates the request and returns `402 Payment Required`. The standard `PAYMENT-REQUIRED` response header contains the accepted network, asset, payment scheme, and maximum authorized amount. Most AI Gateway models use the `upto` payment scheme, which indicates the maximum a client may be charged.

   ```http
   HTTP/1.1 402 Payment Required
   PAYMENT-REQUIRED: <base64-encoded payment requirements>
   ```
3. The x402 client decodes the payment requirements. The wallet signs an authorization for up to the maximum amount.
4. The client retries the same inference request with the signed authorization in the standard `PAYMENT-SIGNATURE` request header.
5. Cloudflare verifies the authorization and runs the inference request. Cloudflare settles the actual request cost, which cannot exceed the authorized maximum.
6. AI Gateway returns the inference response.

### REST API

At this time, only the `/ai/run` endpoint is available with Machine Payments.

Use the Cloudflare API to call third-party models. Pass your Cloudflare API token in the `Authorization` header, and include `Payment-Method: x402` as a header. If the header is not passed, AI Gateway follows the normal [credential precedence](https://developers.cloudflare.com/ai-gateway/features/unified-billing/#credential-precedence) and may deduct the inference cost from your Unified Billing credit balance.

```bash
# Run `wrangler whoami` to get your account ID to replace $CLOUDFLARE_ACCOUNT_ID,
# and `wrangler auth token` to get an auth token to replace $CLOUDFLARE_API_TOKEN.
curl -iX POST "https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/run" \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Payment-Method: x402" \
  --header "Content-Type: application/json" \
  --data '{
    "model": "z-ai/glm-4.7-flash",
    "input": {
      "max_tokens": 9001,
      "messages": [
        {
          "role": "user",
          "content": "What is Cloudflare?"
        }
      ]
    }
  }'
```

Refer to [REST API](https://developers.cloudflare.com/ai-gateway/usage/rest-api/) for more details.

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