{"uid":"cap_B501JybB0IQ2hCngZkI1I","slug":"model-access-gateway-claude-sonnet-5-5-x402-pay-per-call-0b849caf","name":"Model Access Gateway – Claude Sonnet 5.5 (x402 Pay-Per-Call)","description":"LLM inference API: OpenAI-compatible chat completions for 136 AI models (Claude, GPT, Gemini, Grok, DeepSeek, Qwen, Kimi, GLM), paid per call in USDC on Base with x402. No account, no API key, automatic refund if the model fails.","url":"https://modelaccessgateway.com/llm/claude-sonnet-5.5?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"type":"string","description":"Optional: fixed by the route (anthropic/claude-sonnet-5.5)"},"tools":{"type":"array"},"stream":{"type":"boolean","description":"true: server-sent events after payment"},"messages":{"type":"array","items":{"type":"object","required":["role"],"properties":{"role":{"enum":["system","user","assistant","tool","developer"],"type":"string"},"content":{"type":["string","array","null"]}}},"minItems":1},"max_tokens":{"type":"integer","maximum":16384,"minimum":1,"description":"Optional, default 4096"},"temperature":{"type":"number","maximum":2,"minimum":0},"response_format":{"type":"object"}}},"responseSchema":{"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}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.0014","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.0014/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0014","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0014","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_cEPyF5xhbaeoRElZP2iWQ","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.0014","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Runs an OpenAI-compatible chat completion request against Claude Sonnet 5.5 (Anthropic), paid per call in USDC on Base via x402, with no API key or account required.","exampleAgentPrompt":"Ask Claude Sonnet 5.5 to summarize the following meeting transcript in three bullet points, paying with USDC on Base — no API key needed: [transcript text]","exampleUseCases":[{"title":"Autonomous agent with no API credentials","prompt":"I'm building an agent that needs to call Claude on the fly without storing API keys — can you send this conversation to Claude Sonnet 5.5 and get the response back, paying per call in USDC?"},{"title":"One-shot document drafting via Claude","prompt":"Use Claude Sonnet 5.5 to rewrite this legal clause in plain English, keep the response under 500 tokens, and pay for the inference in USDC automatically."},{"title":"Tool-calling pipeline with Claude","prompt":"Send this function-calling request to Claude Sonnet 5.5 with the tools I've defined, stream the response, and handle the USDC micropayment automatically — I don't have an Anthropic key set up."}],"resultDescription":"Returns a standard OpenAI-format chat.completion JSON object containing the assistant's reply, token usage (prompt, completion, total), finish reason (e.g. 'stop'), model identifier ('anthropic/claude-sonnet-5.5'), and a unique completion ID. Streaming mode delivers server-sent events. Payment is deducted per call in USDC; automatic refund is issued if the model fails.","failureModes":["Insufficient USDC balance — payment rejected before inference runs","Model failure — automatic refund issued, no charge","Invalid messages array (empty or malformed) — 400 error","max_tokens out of range (must be 1–16384) — 400 validation error","temperature out of range (0–2) — 400 validation error","Streaming not supported by client — SSE parsing errors if stream:true","Network timeout before response completes — partial or no output"],"whenToPreferThis":"Prefer this endpoint when you need Claude Sonnet 5.5 specifically (Anthropic's model) without managing an Anthropic account or API key, want true pay-per-call billing in USDC (no monthly subscription), are building autonomous agents that need self-sovereign access to frontier models, or need OpenAI-compatible request format with automatic crypto micropayment handling via x402.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-18T06:35:16.972Z","isFirstParty":false,"canonicalSlug":"model-access-gateway-claude-sonnet-5-5-x402-pay-per-call-0b849caf"}