GPT 5.6 Luna
OpenAI · text, image → text
GPT-5.6 Luna is designed for cost-sensitive, high-volume workloads. It roughly corresponds to the nano model tier used in earlier GPT-5 families.
Input$0.2 /M
Output$1.2 /M
Cache read$0.02 /M
← ModelsGPT 5.6 Luna
Step 3.7 Flash
GPT 5.6 Luna vs Step 3.7 Flash
Compare GPT 5.6 Luna 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 5.6 LunaStep 3.7 Flash+ Add model · 2/4
Step 3.7 Flash
StepFun · text, image, video → text
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.
Input$0.22 /M
Output$1.32 /M
Cache read$0.044 /M
Pricing & Specifications
Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.
GPT 5.6 Luna
Step 3.7 Flash
Input /M
$0.2
$0.22
Output /M
$1.2
$1.32
Cache read /M
$0.02
$0.044
Context length
1,050,000
256,000
Max output
128,000
0
Time to First Token
5.1 s
1.4 s
Throughput
47.6 tok/s
32.6 tok/s
Modalities
textimage
textimagevideo
Supported Parameters
toolsthinkingstructured outputs
API Formats
chat_completions · responses
Released
July 9, 2026
May 29, 2026
Promotional prices show the discounted rate; see each model page for promotion windows.
Activity Past 30 Days
Daily traffic served through AIHubMix — how demand for each model is trending.
gpt-5.6-lunastep-3.7-flash
Tokens / day
-
Requests / day
-
Performance Past 3 Days
Measured on real AIHubMix traffic, hourly buckets. Gaps mean no traffic in that hour.
gpt-5.6-lunastep-3.7-flash
Throughput (tok/s)
-
TTFT (s)
-
Uptime (%)
-
Cost calculator
Estimate your monthly bill for the same workload on each model.
GPT 5.6 Luna
$30.00 /mo
Step 3.7 Flash
$33.00 /mo
Monthly = daily × 30. Discounted rates applied where a promotion is active.
FAQ
Which is cheaper: GPT 5.6 Luna, Step 3.7 Flash?
GPT 5.6 Luna: $1.2/M output tokens; Step 3.7 Flash: $1.32/M. Use the cost calculator above to estimate your own workload.
Which responds faster?
Step 3.7 Flash: 1.4s time to first token measured on AIHubMix; see the live performance charts above for how each model behaves across the day.
How large is each context window?
GPT 5.6 Luna accepts 1,050,000 and Step 3.7 Flash accepts 256,000 input tokens.
Which one generates tokens faster?
GPT 5.6 Luna at 47.6 tok/s and Step 3.7 Flash at 32.6 tok/s, measured as output throughput on AIHubMix — a separate metric from time to first token.
What inputs and capabilities does each model support?
GPT 5.6 Luna accepts text and image input and supports tool calling, thinking and structured outputs; Step 3.7 Flash accepts text, image and video input.
Can I call GPT 5.6 Luna and Step 3.7 Flash with the same API key?
Yes. AIHubMix serves every model on this page behind one OpenAI-compatible endpoint, so switching between them is a one-line change to the model field — no second account, key or SDK.
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