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XFuel Paid Inference via x402
x402
XFuel Paid Inference via x402 is a paid API for AI agents from api.xfuel.app, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-18).
Runs a paid AI inference task on Base mainnet USDC via the x402 payment protocol, returning a signed receipt and verification URL
Price / call$0.002
Success—
StatusUnknown
How this service works
OpenAI-compatible paid inference via x402 USDC on Base and Solana ($0.01). POST /v1/chat/completions is the recommended surface. Returns signed receipt + public verify_url. Paying this host is real mainnet USDC.
Output
Returns a signed receipt confirming the USDC payment on Base mainnet, a verify_url for on-chain payment verification, and the AI-generated inference output from the selected model.
Example use cases
On-chain AI assistant with payment proof
“Using my wallet 0xDe4...789, send a $0.01 USDC inference request on Base to XFuel with the xfuel/auto model — user message is 'Summarize the key benefits of proof-of-stake blockchains in 3 bullet points' — max 300 tokens, and give me back the signed receipt so I can verify the payment.”
Agent pipeline with verifiable LLM call
“I need my autonomous agent to call XFuel with USDC on Base from address 0xF12...456, route to the xfuel/auto model, send the system prompt 'You are a code reviewer' and user message 'Review this Python function for bugs: def add(a,b): return a-b', budget 500 tokens, and store the verify_url from the receipt for auditing.”
Paid content generation for crypto app
“Have XFuel generate marketing copy for me — use wallet 0xA99...321, pay 0.01 USDC on Base, use the xfuel/auto model, system message is 'You are a crypto copywriter', user message is 'Write a two-sentence tagline for a DeFi yield aggregator called YieldWave', and keep it under 150 tokens.”
Technical details
Endpoint
POSThttps://api.xfuel.app/task-request?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need verifiable, pay-per-call AI inference with on-chain USDC payment receipts on Base mainnet via the x402 protocol — especially in autonomous agent pipelines where auditability, micropayment receipts, and crypto-native payment rails matter. Prefer this over free or subscription-based LLM APIs when you need signed proof of payment, when operating in a trustless or multi-agent environment, or when the calling agent holds USDC and needs to avoid API key management.
Side effects
- Insufficient USDC balance or allowance causes payment rejection
- Invalid or non-checksummed sender address returns 400 error
- Unsupported model_id returns model-not-found error
- Amount below minimum (10000 base units / $0.01) is rejected
- Wrong chain_id value causes settlement failure
- Malformed messages array (missing role or content) causes validation error
- Network congestion on Base may delay payment settlement
- Rate limiting if too many requests are sent in quick succession
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| amount | string | Gross task value in USDC base units (6 decimals) |
| sender | string | 0x address that owns/pays for the task |
| payment | object | |
| chain_id | string | Settlement chain; "base" for USDC settlement |
| messages | array | OpenAI-style chat messages array |
| model_id | string | Model id from GET /v1/models; xfuel/auto routes automatically |
| input_hash | string | keccak256 of your input (optional; for proof binding) |
| max_tokens | integer | Output token budget (default 500) |
| message_type | string | Task type; only inference_request is supported via x402 |
Output
Schema · Response
{
"type": "json",
"example": {
"status": "accepted",
"task_id": "ai-task-12345",
"fee_amount": "250",
"net_amount": "49750",
"verify_url": "https://api.xfuel.app/receipt/ai-task-12345",
"payment_ref": "base:0x...",
"gross_amount": "50000",
"payment_rail": "usdc"
}
}Tags
x402
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