Step 3.5 Flash 2603 vs Seed 2.0 Mini vs MiMo-V2.5
Too close to call on our weighted score (Seed 2.0 Mini 80, MiMo-V2.5 79, Step 3.5 Flash 2603 62). The right pick depends on what you value most.
StepFunStep 3.5 Flash 2603
62/100- ECI—
- Price$0.10 / $0.30
- Context256K
ByteDance SeedSeed 2.0 Mini
80/100- ECI—
- Price$0.03 / $0.297
- Context256K
XiaomiMiMo-V2.5
79/100- ECI—
- Price$0.14 / $0.28
- Context1.05M
Too close to call
It is close. Our weighted score puts them within 1 points (Seed 2.0 Mini 80/100, MiMo-V2.5 79/100, Step 3.5 Flash 2603 62/100), so choose by what matters most for your work: Seed 2.0 Mini on price and MiMo-V2.5 for long inputs. 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 priceSeed 2.0 MiniSeed 2.0 Mini $0.097 · Step 3.5 Flash 2603 $0.15 · MiMo-V2.5 $0.175 per 1M tokens (3:1 blend)
- Longest contextMiMo-V2.5MiMo-V2.5 1,048,576 · Step 3.5 Flash 2603 256,000 · Seed 2.0 Mini 256,000 tokens
- Widest inputsMiMo-V2.5Step 3.5 Flash 2603: Text · Seed 2.0 Mini: Text, Images, Video · MiMo-V2.5: Text, Images, Audio, Video
- Self-hostingStep 3.5 Flash 2603 and MiMo-V2.5Publishes downloadable weights
| Measure | Weight | Step 3.5 Flash 2603 | Seed 2.0 Mini | MiMo-V2.5 |
|---|---|---|---|---|
| Price | 50% | 89 | 98 | 86 |
| Inputs & features | 30% | 35 | 80 | 80 |
| Context window | 20% | 36 | 36 | 61 |
| Overall | 100% | 62/100 | 80/100 | 79/100 |
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 3.5 Flash 2603StepFun | Seed 2.0 MiniByteDance Seed | MiMo-V2.5Xiaomi |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.10 | $0.03 (best) | $0.14 |
| Output | $0.30 | $0.297 | $0.28 (best) |
| Cached input | $0.02 | $0.0059 | $0.0028 (best) |
| Blended (3:1) | $0.15 | $0.097 (best) | $0.175 |
| Long-context rate | Same rate | Over 32K: $0.059 / $0.594 | Same rate |
| Price source | Official StepFun (Global) API | Official Volcengine Ark API | Official Xiaomi API |
| Limits | |||
| Context window | 256,000 tokens | 256,000 tokens | 1,048,576 tokens (best) |
| Max output | 256,000 tokens (best) | 32,000 tokens | 131,072 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | No | No |
| Audio | No | No | Yes |
| Video | No | Yes | Yes |
| Reasoning | Yeslow · high | Yesminimal · low · medium · high · xhigh · max | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | No | Yes | No |
| Availability | |||
| Weights | Open | Proprietary | Open |
| API model ID | step-3.5-flash-2603 | doubao-seed-2-0-mini-260428 | mimo-v2.5 |
| API providers | 3 | 8 | 21 (best) |
| Released | Apr 2, 2026 | Feb 14, 2026 | Apr 22, 2026 |
| Knowledge cutoff | Jan 2025 | — | 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 3.5 Flash 2603$1.60
- Seed 2.0 Mini$0.891
- MiMo-V2.5$1.96
Which should you choose?
Which is better: Step 3.5 Flash 2603, Seed 2.0 Mini or MiMo-V2.5?
It is close. Our weighted score puts them within 1 points (Seed 2.0 Mini 80/100, MiMo-V2.5 79/100, Step 3.5 Flash 2603 62/100), so choose by what matters most for your work: Seed 2.0 Mini on price and MiMo-V2.5 for long inputs. 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 3.5 Flash 2603, Seed 2.0 Mini or MiMo-V2.5?
Seed 2.0 Mini is cheaper at $0.03 input / $0.297 output per million tokens (official Volcengine Ark API price). Step 3.5 Flash 2603 costs $0.10 input / $0.30 output per million tokens (official StepFun (Global) API price); MiMo-V2.5 costs $0.14 input / $0.28 output per million tokens (official Xiaomi API price). At a typical mix of three input tokens to one output token, that is $0.097 per million tokens for Seed 2.0 Mini versus $0.15 for Step 3.5 Flash 2603 (1.6× as much) and $0.175 for MiMo-V2.5 (1.8× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Step 3.5 Flash 2603 has not been scored yet, Seed 2.0 Mini has not been scored yet and MiMo-V2.5 has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Step 3.5 Flash 2603, Seed 2.0 Mini and MiMo-V2.5 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 has the largest context window at 1,048,576 tokens, against 256,000 for Step 3.5 Flash 2603 and 256,000 for Seed 2.0 Mini. Maximum output per response: Step 3.5 Flash 2603 up to 256,000, Seed 2.0 Mini up to 32,000, MiMo-V2.5 up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Step 3.5 Flash 2603 accepts text; Seed 2.0 Mini accepts text, images and video; MiMo-V2.5 accepts text, images, audio and video. MiMo-V2.5 handles the widest range of inputs.
Are any of these open source?
Step 3.5 Flash 2603 and MiMo-V2.5 publishes its weights and can be self-hosted; Seed 2.0 Mini is proprietary.
Which is newer?
MiMo-V2.5 is the newest, released Apr 22, 2026. Step 3.5 Flash 2603 came out Apr 2, 2026; Seed 2.0 Mini came out Feb 14, 2026. Knowledge cutoff: Step 3.5 Flash 2603 Jan 2025, MiMo-V2.5 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.
