{"uid":"cap_1uBmjvhrRCn-5t5ne6z-s","slug":"openai-gpt-5-nano-chat-completions-x402-usdc-87a378f8","name":"OpenAI GPT-5 Nano Chat Completions (x402/USDC)","description":"gpt-5-nano: OpenAI GPT 5 Nano chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 0.025/0.2, Standard 0.05/0.4; pick with service_tier. Plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Levels: minimal, low, medium, high (model gpt-5-nano:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing","url":"https://openai.mm.family/x402/v1/models/gpt-5-nano/chat/completions?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"enum":["gpt-5-nano","gpt-5-nano:minimal","gpt-5-nano:low","gpt-5-nano:medium","gpt-5-nano:high"],"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-nano","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":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_QeWf5LiAsaV8tDhBkOnkw","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Runs OpenAI GPT-5 Nano chat completions via a pay-per-call x402 API billed in USDC, with selectable quality levels and service tiers.","exampleAgentPrompt":"Send this message to GPT-5 Nano at the 'high' quality level using the standard service tier: 'Explain the difference between supervised and unsupervised learning in three sentences.' Give me up to 300 tokens in the response.","exampleUseCases":[{"title":"High-volume cheap text classification","prompt":"I need to classify thousands of short customer reviews as positive, negative, or neutral — use gpt-5-nano at the minimal quality level with flex tier to keep costs as low as possible. Here's the first one: 'Delivery was late but the product itself was great.'"},{"title":"Crypto-native chatbot backend","prompt":"My app doesn't use OpenAI API keys — I want to call GPT-5 Nano chat completions and pay per call in USDC. Use the medium quality level and standard tier, send the message: 'What are three creative names for a coffee shop?', and limit the reply to 150 tokens."},{"title":"Quality-tuned reasoning for agent pipeline","prompt":"I'm building an agent that needs to summarize legal clauses — use gpt-5-nano:high with standard service tier, send it this system message: 'You are a legal summarizer', and user message: 'Summarize the following indemnification clause in plain English: [clause text]', with up to 500 tokens."}],"resultDescription":"Returns a JSON chat completion object containing the assistant's reply message, finish reason (e.g. 'stop'), prompt and completion token counts, the model variant used, and the service tier applied. Empty responses when the answer is empty are billed at zero.","failureModes":["Insufficient USDC payment causes 402 Payment Required response","Invalid model enum value returns 400 Bad Request","max_tokens quota exceeded leads to truncated response with finish_reason='length'","Invalid service_tier value returns validation error","Network or upstream OpenAI outage causes 502/503 errors","Malformed messages array (missing role or content) causes 400 error"],"whenToPreferThis":"Choose this endpoint when you need the cheapest OpenAI-compatible chat completions with per-call USDC billing — ideal for high-volume, cost-sensitive pipelines, crypto-native apps that avoid traditional API keys, or scenarios where you want to tune quality vs cost via model level (minimal/low/medium/high) and service tier (flex vs standard). Prefer it over gpt-4o or gpt-5.4-mini siblings when token cost is the primary constraint.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T12:40:45.284Z","isFirstParty":false,"canonicalSlug":"openai-gpt-5-nano-chat-completions-x402-usdc-87a378f8"}