Api Endpoint

claude-sonnet-api

Claude Sonnet API - pay per call, no API key. OpenAI-format chat completions on anthropic/claude-sonnet-5.5, pinned to Anthropic's own OpenRouter endpoint for reliability. You sign a fixed price computed from your max_tokens; unused tokens are not refunded. 20s server-side timeout - never charged if it fires; set your client timeout to 30s. Try GET /llm/claude-sonnet/sample.

Open interactive test console

Offering

Provider: x402.agentindex.world
Method: POST
Offering type: Api Endpoint
Transport type: http
Category: Api
Delivery: Not provided
Pricing model: Not provided
x402 version: 2

Endpoint context

URL: https://x402.agentindex.world/llm/claude-sonnet
MIME type: application/json
First seen: 2026-10-16T01:50:38.788Z
Last seen: 2026-11-02T01:32:08.759Z
Tags: Claude Sonnet API, claude api, anthropic api, pay per call llm, chat completion llm, llm api, language model api

Website

Payment pricing

x402 payment terms are the authoritative price for calling this endpoint.

Payment option 1: 0.011264 USDC
Atomic price: 11264 · Network: eip155:8453 · Asset: USDC · Scheme: exact

Raw x402 terms

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "11264",
    "payTo": "0xb3F32bdfe8D07825BC0D7387295aB1D7559BA69d"
  }
]

Observed health

Status: Unreachable
Latest latency: 5002 ms
Average latency: 1584 ms
HTTP status: Not provided
Last checked: 2026-11-04T09:55:17.922Z
Reachability: 91.7% over 12 checks

Latency is measured to the first response headers. A reachable result does not verify response accuracy or merchant identity.

Input schema

{
  "body": {
    "max_tokens": 150,
    "messages": [
      {
        "content": "Summarize in one sentence: The Eiffel Tower is a wrought-iron lattice tower on the Champ de Mars in Paris, France. It was designed by Gustave Eiffel's engineering company and built as the entrance arch for the 1889 World's Fair. Initially criticized by some of France's leading artists and intellectuals for its design, it has become a global cultural icon of France and one of the most recognizable structures in the world, attracting millions of visitors every year.",
        "role": "user"
      }
    ]
  },
  "bodyType": "json",
  "method": "POST",
  "type": "http"
}

Output schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "input": {
      "additionalProperties": false,
      "properties": {
        "body": {
          "properties": {
            "max_tokens": {
              "description": "Max completion tokens, capped at 4096 - also bounds the price ceiling.",
              "type": "integer"
            },
            "messages": {
              "description": "OpenAI-format chat messages: [{role, content}, ...].",
              "items": {
                "type": "object"
              },
              "minItems": 1,
              "type": "array"
            }
          },
          "required": [
            "messages"
          ]
        },
        "bodyType": {
          "enum": [
            "json",
            "form-data",
            "text"
          ],
          "type": "string"
        },
        "method": {
          "enum": [
            "POST",
            "PUT",
            "PATCH"
          ],
          "type": "string"
        },
        "type": {
          "const": "http",
          "type": "string"
        }
      },
      "required": [
        "type",
        "method",
        "bodyType",
        "body"
      ],
      "type": "object"
    },
    "output": {
      "properties": {
        "example": {
          "properties": {
            "choices": {
              "items": {
                "type": "object"
              },
              "type": "array"
            },
            "id": {
              "type": "string"
            },
            "model": {
              "type": "string"
            },
            "usage": {
              "type": "object"
            },
            "x402_receipt": {
              "type": "object"
            }
          },
          "required": [
            "choices",
            "usage"
          ],
          "type": "object"
        },
        "type": {
          "type": "string"
        }
      },
      "required": [
        "type"
      ],
      "type": "object"
    }
  },
  "required": [
    "input"
  ],
  "type": "object"
}