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Model Access Gateway – Claude Sonnet 5.5 via x402
x402
Model Access Gateway – Claude Sonnet 5.5 via x402 is a paid API for AI agents from agent402-arb.rosariovitale0096.workers.dev, paid per call via x402, $0.0014/call, status unknown (last checked 2026-10-15).
Runs OpenAI-compatible chat completions against Claude Sonnet 5.5, billed per request in USDC on Base using the x402 payment protocol — no account or API key required.
Price / call$0.0014
Success—
StatusUnknown
How this service works
Claude Sonnet 5.5 API (anthropic/claude-sonnet-5.5): LLM inference via OpenAI-compatible chat completions, pay per call in USDC on Base with x402. No API key, no account. Suited for AI agents and scripts that need Claude Sonnet 5.5 on demand. When listed, this request cost 30% less than the same request on BlockRun. Streaming and function calling supported. Exact price in the 402 quote before payment; automatic refund if the model fails to answer.
Output
Returns an OpenAI-compatible chat.completion JSON object containing the assistant's message content, finish reason (e.g. 'stop'), model name ('anthropic/claude-sonnet-5.5'), a unique completion ID, creation timestamp, and token usage breakdown (prompt, completion, total tokens).
Example use cases
Keyless LLM call from autonomous agent
“I'm building an agent that needs to call Claude Sonnet 5.5 without managing API keys — just pay per request in USDC on Base. Send it the system prompt 'You are a concise legal summarizer' and the user message 'What are the main clauses in a standard NDA?' and give me the response.”
Crypto-native chatbot backend
“My dApp needs an AI backend that bills in USDC with no subscription. Route this chat turn to Claude Sonnet 5.5: system prompt is 'You are a DeFi assistant', user says 'Explain impermanent loss in one paragraph'. Pay the x402 fee and return the completion.”
On-demand text generation for Web3 workflow
“As part of my automated on-chain workflow, generate a short product description for a new NFT collection called 'Neon Foxes' — whimsical tone, two sentences — using Claude Sonnet 5.5 and settle the cost in USDC per request.”
Technical details
Endpoint
POSThttps://agent402-arb.rosariovitale0096.workers.dev/llm/claude-sonnet-5.5?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to call Claude Sonnet 5.5 without registering for an Anthropic account or managing API keys, especially in autonomous agent or Web3 contexts where paying per request in USDC on Base (via x402) is preferable to a subscription. It is OpenAI SDK-compatible, so existing code requires minimal changes. Prefer alternatives if you need streaming responses, function calling, vision, or guaranteed SLA.
Side effects
- Insufficient USDC balance causes x402 payment failure and request rejection
- Malformed OpenAI-format body (missing messages array) returns 400 Bad Request
- Model identifier path mismatch returns 404 or model-not-found error
- Rate limiting or Workers concurrency limits may return 429 or 503
- Network timeout on Cloudflare Worker edge may return 524 or 502
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| model | string | Optional: fixed by the route (anthropic/claude-sonnet-5.5) |
| tools | array | |
| stream | boolean | true: server-sent events after payment |
| messages | array | |
| max_tokens | integer | Optional, default 4096 |
| temperature | number | |
| response_format | object |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "chatcmpl-7f3c2a91",
"model": "anthropic/claude-sonnet-5.5",
"usage": {
"total_tokens": 10,
"prompt_tokens": 9,
"completion_tokens": 1
},
"object": "chat.completion",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "OK"
},
"finish_reason": "stop"
}
],
"created": 1791979200
}
}Tags
x402
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