Chit402 Responses — x402 Paid AI Inference with Receipt

x402

Chit402 Responses — x402 Paid AI Inference with Receipt is a paid API for AI agents from api.xfuel.app, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Submits a paid AI inference task via x402 USDC micropayment on Base, returning a verifiable receipt with task ID and payment reference

Price / call$0.002

Seller volume →—

Success—

StatusUnknown

How this service works

Chit402: the x402 receipt that doesn't leave you. Hub, model, amount — you hold the book.

Output

Returns a JSON object with status 'accepted', a unique task_id, fee_amount and net_amount in USDC base units, the gross_amount submitted, a verify_url for receipt auditing, a payment_ref (on-chain Base transaction reference), and the payment_rail used.

Example use cases

Agent pipeline with auditable AI spend

“My agent at 0xDe4f... needs to run inference on xFuel using the xfuel/auto model — charge 50000 USDC base units on Base, send the message 'Draft a one-paragraph product description for a noise-cancelling headphone', cap output at 400 tokens, and return the receipt URL so our accounting system can log the payment reference.”

Crypto-native app paying per LLM call

“Submit a paid AI task for sender 0x9Fa2... on Base chain — 25000 USDC base units, model xfuel/auto, message type inference_request — asking 'What are three key risks in DeFi lending protocols?' with a 200-token budget, and give me the task ID and verify URL when it's accepted.”

Proof-bound inference for dispute resolution

“Run a paid inference request from wallet 0xB77c... using the xfuel/auto model, gross amount 75000 USDC base units on Base, include the keccak256 input hash 0xabc...def for proof binding, ask 'Explain the legal concept of force majeure in two sentences', 150 max tokens — I need the verify URL and payment reference to settle a dispute.”

Technical details

Endpoint

POSThttps://api.xfuel.app/v1/responses

When to prefer

Choose this endpoint when you need a verifiable, auditable receipt for each AI inference call — especially in agent pipelines where on-chain proof of payment and post-hoc auditability matter. It is preferable over generic LLM APIs when you require USDC micropayment settlement on Base via x402, cost-plus transparent pricing, and a task receipt URL you retain independently of the agent wallet state.

Side effects

Insufficient or missing x402 payment header causes 402 Payment Required
Invalid or unrecognized model_id returns an error; use GET /v1/models to list valid IDs
Malformed sender address or chain_id mismatch results in rejection
Input hash mismatch between provided input_hash and actual payload triggers validation failure
USDC balance insufficient for declared amount causes payment failure
Unsupported message_type (anything other than inference_request) returns 400
Network or settlement delay on Base chain may delay task acceptance confirmation

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"
  }
}

Reviews

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How this service works

Chit402: the x402 receipt that doesn't leave you. Hub, model, amount — you hold the book.

Output

Example use cases

Agent pipeline with auditable AI spend

Crypto-native app paying per LLM call

Proof-bound inference for dispute resolution

Technical details

Endpoint

POSThttps://api.xfuel.app/v1/responses

When to prefer

Side effects

Insufficient or missing x402 payment header causes 402 Payment Required
Invalid or unrecognized model_id returns an error; use GET /v1/models to list valid IDs
Malformed sender address or chain_id mismatch results in rejection
Input hash mismatch between provided input_hash and actual payload triggers validation failure
USDC balance insufficient for declared amount causes payment failure
Unsupported message_type (anything other than inference_request) returns 400
Network or settlement delay on Base chain may delay task acceptance confirmation

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"
  }
}