{"uid":"cap_PQo0UOfTY2M8TOyqzZIar","slug":"openai-gpt-5-5-chat-completions-x402-usdc-d842ef21","name":"OpenAI GPT-5.5 Chat Completions (x402/USDC)","description":"gpt-5.5: OpenAI GPT 5.5 (<=272K input tokens) chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 2.5/15.0, Standard 5.0/30.0, Fast 12.5/75.0; pick with service_tier. Plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Levels: none, low, medium, high, xhigh (model gpt-5.5:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing","url":"https://openai.mm.family/x402/v1/models/gpt-5.5/chat/completions?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"enum":["gpt-5.5","gpt-5.5:none","gpt-5.5:low","gpt-5.5:medium","gpt-5.5:high","gpt-5.5:xhigh"],"type":"string"},"tools":{"type":"array"},"stream":{"type":"boolean"},"messages":{"type":"array","items":{"type":"object","required":["role","content"],"properties":{"role":{"type":"string"},"content":{"type":"string"}}}},"max_tokens":{"type":"integer"},"service_tier":{"enum":["flex","default","standard","auto","fast","priority"],"type":"string"},"response_format":{"type":"object"},"reasoning_effort":{"type":"string"}}},"responseSchema":{"type":"json","example":{"id":"chatcmpl-x","model":"gpt-5.5","usage":{"total_tokens":9,"prompt_tokens":8,"completion_tokens":1},"object":"chat.completion","choices":[{"index":0,"message":{"role":"assistant","content":"Hello","refusal":null},"finish_reason":"stop"}],"service_tier":"flex"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001284","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":"$0.001284/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001284","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001284","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Mqp1dP_fq7TqCLkgcNieI","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001284","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Runs GPT-5.5 chat completions with up to 272K input tokens, billed per call in USDC via the x402 protocol with configurable service tiers.","exampleAgentPrompt":"Using GPT-5.5 on the openai.mm.family x402 gateway, send this conversation — system: 'You are a helpful assistant', user: 'Explain quantum entanglement in two sentences' — with standard service tier, max 200 tokens, and pay per call in USDC.","exampleUseCases":[{"title":"Crypto-native agent reasoning task","prompt":"I need you to use GPT-5.5 via the x402 USDC-billed API to answer a multi-step reasoning question: 'A train leaves Chicago at 9am going 60mph and another leaves Denver at 10am going 80mph — when do they meet?' Use the flex tier and allow up to 500 tokens."},{"title":"Real-time customer support reply generation","prompt":"Generate a polite, helpful customer support reply using GPT-5.5 at the fast service tier (up to 300 tokens) for this message: 'My order #48291 hasn't arrived and it's been 2 weeks, what do I do?' — bill it per call in USDC."},{"title":"Code explanation for developer tool","prompt":"Ask GPT-5.5 on the x402 endpoint to explain what this Python function does: 'def fib(n): return n if n<=1 else fib(n-1)+fib(n-2)' — use the standard tier, set max_tokens to 400, and pay with USDC."}],"resultDescription":"Returns a JSON chat completion object containing the assistant's message text, the model used, finish reason (e.g. 'stop'), token counts (prompt, completion, total), the service tier applied, and a unique completion ID. Empty completions are returned free of charge.","failureModes":["Insufficient USDC balance causes payment failure before completion","Context length exceeds 272K tokens — use the long-context sibling endpoint instead","Invalid service_tier value causes request rejection","max_tokens set too high leads to over-quoted charges","Model variant string not in allowed enum causes 422 error","Streaming mode (stream:true) may require special client handling"],"whenToPreferThis":"Choose this endpoint when you need GPT-5.5 specifically (not gpt-4o or gpt-5-mini), want to pay per call in USDC via x402 micropayments without a traditional OpenAI API key subscription, need up to 272K input context (use the long-context sibling for more), or want to control cost-vs-latency tradeoffs via service_tier (flex for cheapest, fast for lowest latency). Prefer over sibling models when GPT-5.5 capability level is the target and the context fits within 272K tokens.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T12:39:35.700Z","isFirstParty":false,"canonicalSlug":"openai-gpt-5-5-chat-completions-x402-usdc-d842ef21"}