Step 5 Preview vs MiMo-V2.5-Pro-UltraSpeed vs LongCat-2.5-Preview
Step 5 Preview comes out ahead, 57 to 52 and 43 on our weighted score, though LongCat-2.5-Preview is 9% cheaper per token.
- Our pick
StepFunStep 5 Preview
57/100- ECI—
- Price$1.00 / $2.70
- Context1M
XiaomiMiMo-V2.5-Pro-UltraSpeed
43/100- ECI—
- Price$1.30 / $2.61
- Context1.05M
Meituan (LongCat)LongCat-2.5-Preview
52/100- ECI—
- Price$0.75 / $2.95
- Context1M
Step 5 Preview is our pick
Step 5 Preview is the better all-round choice, scoring 57/100 against LongCat-2.5-Preview (52) and MiMo-V2.5-Pro-UltraSpeed (43). It leads on inputs & features. LongCat-2.5-Preview wins on price. 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 priceLongCat-2.5-PreviewLongCat-2.5-Preview $1.30 · Step 5 Preview $1.43 · MiMo-V2.5-Pro-UltraSpeed $1.63 per 1M tokens (3:1 blend)
- Longest contextMiMo-V2.5-Pro-UltraSpeedMiMo-V2.5-Pro-UltraSpeed 1,048,576 · Step 5 Preview 1,000,000 · LongCat-2.5-Preview 1,000,000 tokens
- Widest inputsStep 5 PreviewStep 5 Preview: Text, Images, Video · MiMo-V2.5-Pro-UltraSpeed: Text · LongCat-2.5-Preview: Text, Images
- Self-hostingMiMo-V2.5-Pro-UltraSpeedPublishes downloadable weights
| Measure | Weight | Step 5 Preview | MiMo-V2.5-Pro-UltraSpeed | LongCat-2.5-Preview |
|---|---|---|---|---|
| Price | 50% | 43 | 40 | 44 |
| Inputs & features | 30% | 80 | 35 | 60 |
| Context window | 20% | 60 | 61 | 60 |
| Overall | 100% | 57/100 | 43/100 | 52/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Step 5 PreviewStepFun | MiMo-V2.5-Pro-UltraSpeedXiaomi | LongCat-2.5-PreviewMeituan (LongCat) |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $1.00 | $1.30 | $0.75 (best) |
| Output | $2.70 | $2.61 (best) | $2.95 |
| Cached input | $0.05 | $0.011 (best) | — |
| Blended (3:1) | $1.43 | $1.63 | $1.30 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official StepFun (Global) API | Official Xiaomi API | Median of 1 providers |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) | 1,000,000 tokens |
| Max output | 1,000,000 tokens (best) | 131,072 tokens | 131,072 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | No | Yes |
| PDFs | No | No | No |
| Audio | No | No | No |
| Video | Yes | No | No |
| Reasoning | Yeslow · medium · high | Yes | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | No |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | step-5-preview | mimo-v2.5-pro-ultraspeed | — |
| API providers | 7 (best) | 1 | 2 |
| Released | Sep 16, 2026 | Jun 8, 2026 | Sep 25, 2026 |
| Knowledge cutoff | — | Dec 2024 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Step 5 Preview$15.40
- MiMo-V2.5-Pro-UltraSpeed$18.27
- LongCat-2.5-Preview$13.40
Which should you choose?
Which is better: Step 5 Preview, MiMo-V2.5-Pro-UltraSpeed or LongCat-2.5-Preview?
Step 5 Preview is the better all-round choice, scoring 57/100 against LongCat-2.5-Preview (52) and MiMo-V2.5-Pro-UltraSpeed (43). It leads on inputs & features. LongCat-2.5-Preview wins on price. 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, Step 5 Preview, MiMo-V2.5-Pro-UltraSpeed or LongCat-2.5-Preview?
LongCat-2.5-Preview is cheaper at $0.75 input / $2.95 output per million tokens (median across 1 API provider). Step 5 Preview costs $1.00 input / $2.70 output per million tokens (official StepFun (Global) API price); MiMo-V2.5-Pro-UltraSpeed costs $1.30 input / $2.61 output per million tokens (official Xiaomi API price). At a typical mix of three input tokens to one output token, that is $1.30 per million tokens for LongCat-2.5-Preview versus $1.43 for Step 5 Preview (1.1× as much) and $1.63 for MiMo-V2.5-Pro-UltraSpeed (1.3× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Step 5 Preview has not been scored yet, MiMo-V2.5-Pro-UltraSpeed has not been scored yet and LongCat-2.5-Preview has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Step 5 Preview, MiMo-V2.5-Pro-UltraSpeed and LongCat-2.5-Preview yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three support tool calling for agent workflows.
Which has the bigger context window?
MiMo-V2.5-Pro-UltraSpeed has the largest context window at 1,048,576 tokens, against 1,000,000 for Step 5 Preview and 1,000,000 for LongCat-2.5-Preview. Maximum output per response: Step 5 Preview up to 1,000,000, MiMo-V2.5-Pro-UltraSpeed up to 131,072, LongCat-2.5-Preview up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Step 5 Preview accepts text, images and video; MiMo-V2.5-Pro-UltraSpeed accepts text; LongCat-2.5-Preview accepts text and images. Step 5 Preview handles the widest range of inputs.
Are any of these open source?
MiMo-V2.5-Pro-UltraSpeed publishes its weights and can be self-hosted; Step 5 Preview and LongCat-2.5-Preview is proprietary.
Which is newer?
LongCat-2.5-Preview is the newest, released Sep 25, 2026. Step 5 Preview came out Sep 16, 2026; MiMo-V2.5-Pro-UltraSpeed came out Jun 8, 2026. Knowledge cutoff: MiMo-V2.5-Pro-UltraSpeed Dec 2024.
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.
