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Zeno Finance Responses API (x402)
x402
Zeno Finance Responses API (x402) is a paid API for AI agents from api.zeno.finance, paid per call via x402, $0.016025/call, status unknown (last checked 2026-10-15).
OpenAI-compatible Responses API endpoint that accepts a prompt and returns generated text with token usage and cost, settled via x402 micropayment on Base.
Price / call$0.016025
Success—
StatusUnknown
How this service works
General-purpose Responses API from api.zeno.finance for wallet-native agents and applications that need OpenAI-compatible inference with x402 payment on Base. Pricing starts at $0.001 and is usage-settled up to a $6 per-request cap. Buyers send prompt or structured input and receive concise JSON with output text, tokens spent, and request cost.
Output
A JSON object containing the generated output text, the number of tokens consumed (input and output), and the cost of the request in USDC. Pricing is usage-settled between $0.001 and $6 per request.
Example use cases
Autonomous agent inference with crypto billing
“Use the Zeno Finance Responses API with gpt-5.5 to answer this question for my agent: 'What are the top three DeFi protocols by TVL right now?' — limit to 300 output tokens.”
Structured data extraction via LLM
“Send this instruction to Zeno's Responses API using gpt-5.4-pro: extract the company name, founding year, and CEO from the following text — 'Acme Corp was founded in 2011 by Jane Doe.' Use up to 200 output tokens.”
Crypto-native chatbot response generation
“I'm building a wallet-native chatbot — use the Zeno Finance Responses API with gpt-5.5 to generate a friendly reply to this user message: 'How do I stake ETH safely?' Keep it under 400 tokens.”
Technical details
Endpoint
POSThttps://api.zeno.finance/v1/responses?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need OpenAI-compatible text generation with per-request crypto micropayment settlement on Base via x402, especially for wallet-native agents or applications that cannot hold traditional API subscriptions. Prefer it over standard OpenAI direct access when autonomous agent payment without a credit card or API key subscription is required. The Responses API format (vs Chat Completions) is preferable when using structured instructions and single-turn inference patterns.
Side effects
- Insufficient USDC balance or x402 payment failure — payment not settled, request rejected
- Invalid or unsupported model name — returns error indicating unrecognized model
- Prompt exceeds model context window — returns token limit error
- max_output_tokens set below minimum (1) — validation error
- Rate limiting or provider quota exceeded — 429 or 503 response
- Malformed input JSON — 400 bad request
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | string | Prompt or instruction to send to the Responses API. |
| model | string | Configured model name to run, such as gpt-5.5 or gpt-5.4-pro. |
| instructions | string | Optional system-style instructions for the response. |
| max_output_tokens | number | Maximum number of output tokens to generate. |
Tags
x402
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