Undominated.ai

Cheaper alternatives to Step 3.5 Flash

StepFun LMArena 1403.8 $0.150/M on a balanced workload prices as of 2026-08-28

3 models are both better and cheaper, giving up nothing.

Of the 133 models carrying both an independent score and a published price at the same delivery mode, 5 score at least as high as Step 3.5 Flash and cost no more under at least one workload. 3 match or beat it on every capability we hold — context, maximum output, input modes, tool use and extended reasoning. 2 do not, and every row names what it drops.

Dominance is not a property of a model. It is a property of a model, a capability lens and a workload, and all three are named on every row. Scores are LMArena Elo, used under CC BY 4.0 from the official dataset; prices are blended per million tokens. A higher score is not a drop-in replacement.

This page is built from that comparison and nothing else. When no model is both better and cheaper than Step 3.5 Flash, it is not generated.

Where it holds

WorkloadStep 3.5 Flash $/MBetter and cheaperWith a trade
Balanced$0.15021
Summarise$0.11032
Chat$0.18032
Code gen$0.22020
Agentic$0.13032

Workload mixes are defined on the methodology page. Cached input is priced at the cached rate, and reasoning tokens at the worse of the reasoning and output rates.

What you would be replacing

Intelligence1403.8
Context window262K
Max output66K
Input modestext
Tool useyes
Extended reasoningyes

A replacement has to clear every line above, not just the score. Full record for Step 3.5 Flash.

Better and cheaper, nothing given up 3

Each of these matches or beats Step 3.5 Flash on context, maximum output, input modes, tool use and reasoning, scores at least as high, and costs no more.

#ModelIntelligence$/MHolds under
1Hy3 Tencent1441.2 +37.4$0.144
  • Balanced −4%
  • Summarise −30%
  • Chat −10%
  • Agentic −36%
2DeepSeek V4 Flash 0423 DeepSeek1431.6 +27.8$0.101
  • Balanced −32%
  • Summarise −39%
  • Chat −48%
  • Code gen −43%
  • Agentic −58%
3MiMo-V2.5 Xiaomi1427.3 +23.5$0.108 summarise
  • Summarise −2%
  • Chat −14%
  • Code gen −3%
  • Agentic −39%

Cheaper and higher-scoring, but you give something up 2

These score at least as high and cost no more on the two plotted axes, and lose something that is not on them. Read the last column before switching.

ModelIntelligence$/MHolds underWhat you give up
Gemma 4 26B A4B Google1434.6 +30.8$0.138
  • Balanced −8%
  • Summarise −24%
  • Chat −1%
  • Agentic −15%
  • 66K → 16K max output
Gemma 4 31B Google1441.7 +37.9$0.091 summarise
  • Summarise −17%
  • Chat −1%
  • Agentic −20%
  • 66K → 16K max output

What this compares, and what it leaves out

  • Quality is LMArena Elo, used under CC BY 4.0 from the official dataset. The 95% confidence interval on a difference between two scores is about ±10.68 points, so a gap smaller than that is marked tie rather than an improvement — see significance bands.
  • 188 further models at this delivery mode carry a price but no independent score. They are absent from the comparison in both directions — unrated is not a zero, and an unmeasured model is neither an alternative nor a worse buy.
  • Retired models are never offered as an alternative, and a model only competes against its own delivery mode: batch trades latency for price, so it is not a like-for-like swap.
  • Nothing here measures latency, throughput, rate limits or how a model behaves on your prompts. Two models with the same index score are not interchangeable.
  • The models that nothing beats on both axes are on the value frontier, and every other model something cheaper beats is listed here.