# Zeno Finance Chat Completions API

> Zeno Finance Chat Completions API is a paid API for AI agents from api.zeno.finance, paid per call via x402, $0.016025/call, status unknown (last checked 2026-10-18).

OpenAI-compatible chat completions endpoint with wallet-paid (x402) access, supporting models like GPT-5.5 and settling costs per token used up to $6 per request.

## Facts

- Endpoint: POST https://api.zeno.finance/v1/chat/completions?utm_source=zero.xyz
- Price: $0.016025/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/zeno-finance-chat-completions-api-5c8770be
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DyrRVEuA8MA2_KAXyFExF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability zeno-finance-chat-completions-api-5c8770be -d '<json body>'
```

Example prompt: Send a chat completion request using the GPT-5.5 model with the system message 'You are a concise assistant' and my user message 'Summarize the history of the Roman Empire in 3 bullet points', with a max of 300 tokens — and pay for it from my wallet.

## When to prefer this

Choose this endpoint when your agent or application needs OpenAI-compatible chat completions but must pay via crypto wallet (USDC/x402) rather than a traditional API key subscription. Ideal for autonomous agents that hold their own wallets, on-chain applications, or developers who want usage-settled micro-payment billing instead of prepaid credit. Prefer over standard OpenAI direct access when wallet-native payment or per-request cost transparency is required.

## Known failure modes

- Insufficient wallet balance for the request cost — payment rejected before inference runs
- Model name not recognized or unavailable — returns model not found error
- messages array empty or malformed — validation error before processing
- max_tokens exceeds model context window — truncation or error response
- Request cost exceeds $6 per-request cap — request rejected

## How this service works

General-purpose Chat Completions API from api.zeno.finance for agents and applications that need OpenAI-compatible conversational inference with wallet-paid access. Pricing starts at $0.001 and is usage-settled up to a $6 per-request cap. Buyers receive a standard chat.completion response plus tokens spent and request cost.

## Output

Returns a standard OpenAI-format chat.completion object containing the assistant's reply, plus metadata fields for tokens spent and the actual cost of the request in USDC.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string",
   "description": "Configured model name to run, such as gpt-5.5 or gpt-5.4."
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "developer"
      ],
      "type": "string"
     },
     "content": {
      "type": "string"
     }
    },
    "additionalProperties": false
   },
   "minItems": 1,
   "description": "OpenAI-compatible chat message list."
  },
  "max_tokens": {
   "type": "number",
   "minimum": 1,
   "description": "Maximum number of completion tokens to generate."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/zeno-finance-chat-completions-api-5c8770be/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.zeno.finance](https://www.zero.xyz/host/api.zeno.finance/llms.txt)