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agent402.tools Chat Completions (x402 Pay-Per-Call)
x402
agent402.tools Chat Completions (x402 Pay-Per-Call) is a paid API for AI agents from agent402.tools, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-31).
OpenAI-compatible chat completions endpoint that accepts requests via the OpenAI SDK format and charges per call in USDC over the x402 payment protocol — no API key or signup required.
Price / call$0.02
Success—
StatusUnknown
How this service works
OpenAI-compatible chat completions paid per call in USDC: point any OpenAI SDK at this base URL and send a normal chat request, with the model chosen from a curated list and streaming supported. Use it when an agent needs a model answer without an API key or an account, one call at a time, with a receipt for each.
Output
An OpenAI-compatible chat completion object containing the assistant's reply message, finish reason, and token usage counts (prompt, completion, total). The response mirrors the standard OpenAI /v1/chat/completions response schema.
Example use cases
Example prompt
“Send this conversation to gpt-4o-mini and get a reply — I want to pay per call in USDC, no API key: messages are [{"role":"user","content":"Summarize the French Revolution in 3 bullet points"}], cap the output at 300 tokens.”
Technical details
Endpoint
POSThttps://agent402.tools/v1/chat/completions?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need OpenAI-SDK-compatible chat completions but want to pay per call in USDC via x402 rather than managing API keys or subscriptions. It is ideal for agents operating on crypto-native payment rails (Base, Solana, Polygon, Arbitrum, Stellar), serverless or wallet-authenticated workflows, or when you want budget model access (gpt-4o-mini, Claude Haiku, Gemini Flash) without committing to a monthly plan. Prefer it over the auto-routing sibling endpoint when you want explicit model control.
Side effects
- Payment insufficient or x402 handshake fails — upstream returns 402 with a payment-required header
- Model ID not on the allowed tier allowlist — returns an error listing valid model IDs
- ZDR requested but no zero-data-retention provider available for the chosen model — walks failover chain and may error
- max_tokens exceeds tier maximum — clamped silently or rejected
- Provider upstream timeout or outage — error propagated from OpenRouter
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| zdr | boolean | |
| model | string | |
| tools | array | |
| messages | array | |
| reasoning | object | |
| max_tokens | number | |
| cache_control | — | |
| model_fallback | boolean | |
| max_completion_tokens | integer |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "gen-…",
"model": "openai/gpt-4o-mini",
"usage": {
"total_tokens": 13,
"prompt_tokens": 12,
"completion_tokens": 1
},
"object": "chat.completion",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "OK"
},
"finish_reason": "stop"
}
],
"created": 1750000000
}
}Tags
x402
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