Compare GPT 5.1 from OpenAI and Step 3.7 Flash from StepFun on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the AIHubMix API.
GPT 5.1
Step 3.7 FlashGPT-5 is OpenAI’s most advanced language model, designed for complex tasks that require step-by-step reasoning, precise instruction following, and high reliability. It improves reasoning, code generation, and prompt understanding—including test-time routing and intent cues like “think hard about this”—while reducing hallucination and sycophancy.
step-3.7-flash is stepfun's flagship inference model, designed for high-complexity tasks that require deep reasoning and fast execution. It excels at decomposing multi-step problems, performing tool calls, and maintaining consistency across massive datasets. It is the preferred choice for complex workloads such as long-context agents, advanced software engineering, and end-to-end research automation.
Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.
Promotional prices show the discounted rate; see each model page for promotion windows.
Daily traffic served through AIHubMix — how demand for each model is trending.
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Estimate your monthly bill for the same workload on each model.
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Step 3.7 Flash: $1.32/M output tokens; GPT 5.1: $10/M. Use the cost calculator above to estimate your own workload.
GPT 5.1 accepts 400,000 and Step 3.7 Flash accepts 256,000 input tokens.
GPT 5.1 accepts text, image and PDF input and supports thinking, web search, tool calling, deep search, function calling and structured outputs; Step 3.7 Flash accepts text, image and video input.
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