{"uid":"cap_pwdhR-f170Tll6yLto1m7","slug":"x402-gateway-production-up-railway-app-f2027a16","name":"x402 Gateway – OpenAI o4-mini (Fast Reasoning)","description":"OpenAI's latest small reasoning model — fast chain-of-thought for math, coding, and analysis","url":"https://x402-gateway-production.up.railway.app/api/llm/o4-mini","method":"POST","headers":{},"bodySchema":null,"responseSchema":null,"example":{"request":{"model":"o4-mini","messages":[{"role":"user","content":"Given a list of integers [3, 1, 4, 1, 5, 9], write a Python function that returns all pairs summing to 10 and explain the time complexity."}],"max_tokens":1000},"response":{"model":"openai/o4-mini-2025-04-16","usage":{"cost":0.0044528,"is_byok":false,"cost_details":{"upstream_inference_cost":0.0044528,"upstream_inference_prompt_cost":0.0000528,"upstream_inference_completions_cost":0.0044},"total_tokens":1048,"prompt_tokens":48,"completion_tokens":1000,"prompt_tokens_details":{"audio_tokens":0,"video_tokens":0,"cached_tokens":0,"cache_write_tokens":0},"completion_tokens_details":{"audio_tokens":0,"image_tokens":0,"reasoning_tokens":704}},"content":"Here’s a simple O(n)-time, O(n)-space solution using a hash set to find all unique pairs that sum to a given target (10 in your example):\n\n```python\ndef find_pairs(arr, target):\n    seen = set()      # numbers we’ve seen so far\n    pairs = set()     # store result pairs as (small, large) to avoid dupes\n\n    for x in arr:\n        y = target - x\n        if y in seen:\n            # order the pair so (1,9) and (9,1) aren’t counted separately\n            pairs.add((min(x, y), max(x, y)))\n        seen.add(x)\n\n    # convert set of tuples to a list if you like\n    return list(pairs)\n\n# Example\nnums = [3, 1, 4, 1, 5, 9]\nprint(find_pairs(nums, 10))   # [(1, 9)]\n```\n\nExplanation of time complexity:\n\n- We loop over the list once: O(n) iterations.\n- Each iteration does at most two set operations (`in`-check and `add`), each O(1) on average.\n- So total time is O(n).  \n- We use O(n) extra space for the `seen` set (and up to O(n) for the result set in the worst"}},"exampleRequest":{"model":"o4-mini","messages":[{"role":"user","content":"Given a list of integers [3, 1, 4, 1, 5, 9], write a Python function that returns all pairs summing to 10 and explain the time complexity."}],"max_tokens":1000},"tags":["x402"],"displayCostAmount":"0.03","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","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":"$0.03/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.03","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.03","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_LK75e_TZ9DbaoybGb7YZ4","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.03","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Runs OpenAI's o4-mini small reasoning model via the x402 payment gateway for fast chain-of-thought inference on math, coding, and analysis tasks","exampleAgentPrompt":"Use the o4-mini reasoning model to solve this: given a list of integers [3, 1, 4, 1, 5, 9], write a Python function that returns all pairs summing to 10 and explain the time complexity.","exampleUseCases":null,"resultDescription":"A text completion from OpenAI's o4-mini model containing the model's chain-of-thought reasoning and final answer, covering the math, code, or analytical task submitted in the prompt.","failureModes":["Payment not included or insufficient (HTTP 402) — x402 micropayment required of $0.03 USDC per call","Invalid or malformed prompt body returns 400 Bad Request","Model overloaded or upstream OpenAI error returns 500 or 503","Rate limiting if too many concurrent requests are made","Empty or missing messages field causes request rejection"],"whenToPreferThis":"Choose this endpoint when you need fast, affordable chain-of-thought reasoning — especially for math, coding, logic, or structured analysis — and don't need the full power of a larger frontier model. Ideal for agent pipelines where cost efficiency matters and the task benefits from step-by-step reasoning over raw fluency.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T06:49:06.060Z","isFirstParty":false}