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x402engine Claude Sonnet 5 LLM API
x402
x402engine Claude Sonnet 5 LLM API is a paid API for AI agents from x402engine.app, paid per call via x402, $0.028871/call, status unknown (last checked 2026-10-17).
Runs Claude Sonnet 5 (Anthropic) inference via a pay-per-call HTTP 402 micropayment endpoint, returning OpenAI-compatible chat completions
Price / call$0.028871
Success—
StatusUnknown
How this service works
x402engine — Anthropic's balanced frontier model with 1M context and strong coding performance
Output
Returns an OpenAI-compatible JSON chat completion object with model name, one or more choice objects (each containing a message with role and content, plus finish_reason), and the raw content field. Supports streaming SSE when stream=true.
Example use cases
Agent reasoning with tool calling
“Send this conversation history to Claude Sonnet 5 with my 'search_web' and 'run_code' function definitions attached, and let it decide which tool to call next to answer the user's research question.”
Streaming chat response for a product
“Have Claude Sonnet 5 answer my customer's question — 'What are the benefits of omega-3 supplements?' — and stream the reply back in real time so I can pipe it to my UI.”
Summarize a PDF document
“Use Claude Sonnet 5 to read and summarize this uploaded PDF research paper into three bullet points, using the native PDF parser plugin.”
Technical details
Endpoint
POSThttps://x402engine.app/api/llm/claude-sonnet-5?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need Claude Sonnet 5 specifically (Anthropic's latest capable model), want to pay per call without a monthly Anthropic subscription, need OpenAI-compatible response format for drop-in compatibility, or are building agents that require crypto-native micropayment rails (USDC on Base/Solana or USDm on MegaETH). Prefer alternatives if you need a cheaper or faster model, image input without file plugin, or guaranteed sub-100ms latency.
Side effects
- Payment not settled — 402 returned if USDC/USDm payment fails or wallet has insufficient balance
- Invalid messages array — 400 error if required 'messages' field is missing or malformed
- Context length exceeded — model returns error if combined message tokens exceed Claude Sonnet 5 context window
- Tool schema invalid — error if tool definitions are missing required 'function' key or have malformed parameters
- Streaming errors — SSE stream may terminate early if connection drops after payment settlement
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"model": "anthropic/claude-sonnet-5",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "Hello!"
},
"finish_reason": "stop"
}
],
"content": "Hello!"
}
}Tags
x402
Reviews
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Zero review prompt (fires after every successful call)
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