OpenAI Responses API over x402
OpenAI Responses API over x402 - point the OpenAI SDK's responses.create() (or the OpenAI Agents SDK) at base_url https://agent402.tools/v1/premium and pay $0.50 per call in USDC, no API key, no signup. Same models, caps and price as this tier's /chat/completions route; any model here is served through the Responses wire.
Answeringour last check, 2026-09-24
1 of 1checks answered this week
975 msmedian answer time
$0.5listed price per call
$0.5price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://agent402.tools/v1/premium/responses
| Category | Market data |
|---|---|
| Provider host | agent402.tools |
| Networks | algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=, eip155:10, eip155:1329, eip155:137, eip155:143, eip155:42161, eip155:42220, eip155:43114, eip155:4663, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp, stellar:pubnet |
| Payment schemes | exact, upto |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-24 | valid payment request | 402 | $0.5 | 975 ms |
Example input (from the provider)
{
"body": {
"input": "Summarize x402 in one sentence.",
"model": "anthropic/claude-opus-5"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"input": {
"description": "A string, or an array of input items ({role, content} messages with input_text / input_image parts, function_call, function_call_output)"
},
"instructions": {
"description": "Optional system/developer instructions",
"type": "string"
},
"max_output_tokens": {
"description": "Optional output cap (clamped to the tier cap)",
"type": "integer"
},
"model": {
"description": "Model id (OpenRouter naming) - allowlisted per tier; omit (or \"auto\") on the auto tier",
"type": "string"
},
"reasoning": {
"description": "Optional {effort: \"none\"|\"minimal\"|\"low\"|\"medium\"|\"high\"|\"xhigh\"|\"max\"} - reasoning tokens count against max_output_tokens",
"type": "object"
},
"stream": {
"description": "Responses SSE events (response.created \u2026 response.completed)",
"type": "boolean"
},
"text": {
"description": "Optional {format: {type: \"text\"|\"json_schema\"|\"json_object\", ...}}",
"type": "object"
},
"tools": {
"description": "Optional function tools ({type:\"function\", name, parameters}); server-side tools are not served",
"type": "array"
},
"zdr": {
"description": "Optional - zero-data-retention providers only",
"type": "boolean"
}
},
"required": [
"input"
]
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"id": {
"type": "string"
},
"model": {
"type": "string"
},
"object": {
"type": "string"
},
"output": {
"items": {
"type": "object"
},
"type": "array"
},
"status": {
"type": "string"
},
"usage": {
"properties": {
"input_tokens": {
"type": "integer"
},
"output_tokens": {
"type": "integer"
},
"total_tokens": {
"type": "integer"
}
},
"type": "object"
}
},
"required": [
"id",
"object",
"status",
"model",
"output",
"usage"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}