ZMIME
Comparison · 2 models · Updated Oct 4, 2026

MiMo-V2.5-Pro vs Step 3.5 Flash 2603

Step 3.5 Flash 2603 comes out ahead, 62 to 54 on our weighted score, and it is the cheaper option too.

  1. Xiaomi

    MiMo-V2.5-Pro

    Released Apr 22, 2026

    54/100
    • ECI—
    • Price$0.435 / $0.87
    • Context1.05M
  2. Our pick

    StepFun

    Step 3.5 Flash 2603

    Released Apr 2, 2026

    62/100
    • ECI—
    • Price$0.10 / $0.30
    • Context256K
  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Step 3.5 Flash 2603 is our pick

Step 3.5 Flash 2603 is the better all-round choice, scoring 62/100 against MiMo-V2.5-Pro (54). It leads on price. MiMo-V2.5-Pro wins on context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceStep 3.5 Flash 2603Step 3.5 Flash 2603 $0.15 · MiMo-V2.5-Pro $0.544 per 1M tokens (3:1 blend)
  • Longest contextMiMo-V2.5-ProMiMo-V2.5-Pro 1,048,576 · Step 3.5 Flash 2603 256,000 tokens
  • Widest inputsSame inputsMiMo-V2.5-Pro: Text · Step 3.5 Flash 2603: Text
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightMiMo-V2.5-ProStep 3.5 Flash 2603
Price50%6289
Inputs & features30%3535
Context window20%6136
Overall100%54/10062/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

MiMo-V2.5-Pro vs Step 3.5 Flash 2603 specifications side by side
SpecificationMiMo-V2.5-ProXiaomiStep 3.5 Flash 2603StepFun
Capability
Capabilities Index (ECI)——
ECI rank——
Price per million tokens
Input$0.435$0.10 (best)
Output$0.87$0.30 (best)
Cached input$0.0036 (best)$0.02
Blended (3:1)$0.544$0.15 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Xiaomi APIOfficial StepFun (Global) API
Limits
Context window1,048,576 tokens (best)256,000 tokens
Max output131,072 tokens256,000 tokens (best)
Inputs and features
TextYesYes
ImagesNoNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesYeslow · high
Tool callingYesYes
Structured outputNoNo
Availability
WeightsOpenOpen
API model IDmimo-v2.5-prostep-3.5-flash-2603
API providers20 (best)3
ReleasedApr 22, 2026Apr 2, 2026
Knowledge cutoffDec 2024Jan 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • MiMo-V2.5-Pro$6.09
  • Step 3.5 Flash 2603$1.60
04 — Questions

Which should you choose?

Which is better: MiMo-V2.5-Pro or Step 3.5 Flash 2603?

Step 3.5 Flash 2603 is the better all-round choice, scoring 62/100 against MiMo-V2.5-Pro (54). It leads on price. MiMo-V2.5-Pro wins on context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, MiMo-V2.5-Pro or Step 3.5 Flash 2603?

Step 3.5 Flash 2603 is cheaper at $0.10 input / $0.30 output per million tokens (official StepFun (Global) API price). MiMo-V2.5-Pro costs $0.435 input / $0.87 output per million tokens (official Xiaomi API price). At a typical mix of three input tokens to one output token, that is $0.15 per million tokens for Step 3.5 Flash 2603 versus $0.544 for MiMo-V2.5-Pro (3.6× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. MiMo-V2.5-Pro has not been scored yet and Step 3.5 Flash 2603 has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for MiMo-V2.5-Pro and Step 3.5 Flash 2603 yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

MiMo-V2.5-Pro has the largest context window at 1,048,576 tokens, against 256,000 for Step 3.5 Flash 2603. Maximum output per response: MiMo-V2.5-Pro up to 131,072, Step 3.5 Flash 2603 up to 256,000 tokens.

Which can read images, PDFs, audio or video?

MiMo-V2.5-Pro accepts text; Step 3.5 Flash 2603 accepts text. They handle the same number of input types.

Are any of these open source?

Yes, both publish their weights, so you can self-host them.

Which is newer?

MiMo-V2.5-Pro is the newest, released Apr 22, 2026. Step 3.5 Flash 2603 came out Apr 2, 2026. Knowledge cutoff: MiMo-V2.5-Pro Dec 2024, Step 3.5 Flash 2603 Jan 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.