Step 2 16K
StepFun · → text
Input$2 /M
Output$2 /M
← ModelsStep 2 16KStep 3.5 Flash
Step 2 16K vs Step 3.5 Flash
Compare Step 2 16K from StepFun and Step 3.5 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.
Step 2 16KStep 3.5 Flash+ Add model · 2/4
Step 3.5 Flash
StepFun · text → text
step-3.5-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$0.11 /M
Output$0.33 /M
Pricing & Specifications
Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.
Step 2 16K
Step 3.5 Flash
Input /M
$2
$0.11
Output /M
$2
$0.33
Cache read /M
-
-
Context length
0
256,000
Max output
0
0
Time to First Token
-
1.4 s
Throughput
-
24.6 tok/s
Modalities
text
Supported Parameters
API Formats
Released
January 1, 2025
January 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.
step-2-16kstep-3.5-flash
Tokens / day
-
Requests / day
-
Performance Past 3 Days
Measured on real AIHubMix traffic, hourly buckets. Gaps mean no traffic in that hour.
step-2-16kstep-3.5-flash
Throughput (tok/s)
-
TTFT (s)
-
Uptime (%)
-
LMArena Benchmarks
LMArena ratings by capability (Bradley-Terry, commonly called Elo). Higher is better.
Text
step-2-16kstep-3.5-flash
1280132013601400
Overall
13341393
Coding
13721372
Math
13131313
Hard prompts
13381338
Instruction following
13161316
Multi-turn
13071307
Creative writing
13371337
Longer query
13421342
Chinese
13651365
English
13551355
Source: LMArena (arena.ai) leaderboard, imported by AIHubMix. Models without published ratings are omitted per chart.
Cost calculator
Estimate your monthly bill for the same workload on each model.
Step 3.5 Flash
$11.55 /mo
Step 2 16K
$150 /mo
Monthly = daily × 30. Discounted rates applied where a promotion is active.
FAQ
Which is cheaper: Step 2 16K, Step 3.5 Flash?
Step 3.5 Flash: $0.33/M output tokens; Step 2 16K: $2/M. Use the cost calculator above to estimate your own workload.
Can I call Step 2 16K and Step 3.5 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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