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XFuel A2A Message (OpenAI-Compatible Paid Inference)
x402
XFuel A2A Message (OpenAI-Compatible Paid Inference) is a paid API for AI agents from api.xfuel.app, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-17).
Accepts an OpenAI-style chat completion request over an agent-to-agent message endpoint, processing it via x402 USDC micropayment on Base or Solana mainnet and returning an AI-generated text response with a signed payment receipt.
Price / call$0.002
Success—
StatusUnknown
How this service works
Chit402: the x402 receipt that doesn't leave you. Hub, model, amount — you hold the book.
Output
Returns an OpenAI-compatible chat completion response containing the assistant's generated text, along with a signed payment receipt and a public verify_url that can be used to confirm the USDC micropayment was made on-chain (Base or Solana mainnet).
Example use cases
Autonomous agent AI reasoning loop
“I need my agent to ask the AI model 'What is the best next action given this task list: [buy groceries, schedule dentist, reply to emails]?' — use the xfuel/auto model, limit to 150 tokens, and pay the USDC fee automatically.”
On-chain verifiable AI content generation
“Generate a product description for my new ergonomic chair using the xfuel/auto model — I need a signed receipt proving the AI call was paid for on Base so I can log it for compliance.”
Crypto-native chatbot backend
“Send this user message to the AI with a system prompt saying 'You are a helpful crypto trading assistant' and user message 'What does a bullish engulfing candle pattern indicate?' — use temperature 0.7 and max 300 tokens, paying per call in USDC.”
Technical details
Endpoint
POSThttps://api.xfuel.app/a2a-message?utm_source=zero.xyzWhen to prefer
Choose this endpoint when your agent needs OpenAI-compatible LLM inference with automatic on-chain USDC micropayment at $0.01 per call, especially in crypto-native or agent-to-agent workflows where verifiable payment receipts matter. Prefer it over standard OpenAI API when you need blockchain-verified payment provenance, are operating in a Web3 context, or want to pay per call in stablecoins without a subscription.
Side effects
- Insufficient USDC balance or failed x402 payment — returns payment required or payment failure error
- Invalid or unsupported model ID — returns model not found error
- Malformed messages array missing required role or content fields — returns 400 validation error
- Token budget exceeded or max_tokens too large for selected model — returns context length error
- Network congestion on Base or Solana causing payment confirmation delay — may result in timeout
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| model | string | Model id from GET /v1/models; xfuel/auto routes automatically |
| stream | boolean | |
| messages | array | OpenAI-style chat messages array |
| max_tokens | integer | Output token budget |
| temperature | number |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "chatcmpl-abc123",
"model": "xfuel/auto",
"usage": {
"total_tokens": 15,
"prompt_tokens": 10,
"completion_tokens": 5
},
"xfuel": {
"verify_url": "https://api.xfuel.app/receipt/xfuel-abc123"
},
"object": "chat.completion",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "Hello!"
},
"finish_reason": "stop"
}
],
"created": 1700000000
}
}Tags
x402
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