Seed 2.1 Pro vs Gemini 3.1 Flash Lite vs MiMo-V2.5-Pro-UltraSpeed
Gemini 3.1 Flash Lite comes out ahead, 73 to 50 and 43 on our weighted score, and it is the cheaper option too.
ByteDance SeedSeed 2.1 Pro
50/100- ECI—
- Price$0.891 / $4.45
- Context256K
- Our pick
GoogleGemini 3.1 Flash Lite
73/100- ECI—
- Price$0.25 / $1.50
- Context1.05M
XiaomiMiMo-V2.5-Pro-UltraSpeed
43/100- ECI—
- Price$1.30 / $2.61
- Context1.05M
Gemini 3.1 Flash Lite is our pick
Gemini 3.1 Flash Lite is the better all-round choice, scoring 73/100 against Seed 2.1 Pro (50) and MiMo-V2.5-Pro-UltraSpeed (43). It leads on price and inputs & features. 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 priceGemini 3.1 Flash LiteGemini 3.1 Flash Lite $0.563 · MiMo-V2.5-Pro-UltraSpeed $1.63 · Seed 2.1 Pro $1.78 per 1M tokens (3:1 blend)
- Longest contextGemini 3.1 Flash Lite and MiMo-V2.5-Pro-UltraSpeedGemini 3.1 Flash Lite 1,048,576 · MiMo-V2.5-Pro-UltraSpeed 1,048,576 · Seed 2.1 Pro 256,000 tokens
- Widest inputsGemini 3.1 Flash LiteSeed 2.1 Pro: Text, Images, Video · Gemini 3.1 Flash Lite: Text, Images, PDFs, Audio, Video · MiMo-V2.5-Pro-UltraSpeed: Text
- Self-hostingMiMo-V2.5-Pro-UltraSpeedPublishes downloadable weights
| Measure | Weight | Seed 2.1 Pro | Gemini 3.1 Flash Lite | MiMo-V2.5-Pro-UltraSpeed |
|---|---|---|---|---|
| Price | 50% | 38 | 62 | 40 |
| Inputs & features | 30% | 80 | 100 | 35 |
| Context window | 20% | 36 | 61 | 61 |
| Overall | 100% | 50/100 | 73/100 | 43/100 |
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 | Seed 2.1 ProByteDance Seed | Gemini 3.1 Flash LiteGoogle | MiMo-V2.5-Pro-UltraSpeedXiaomi |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.891 | $0.25 (best) | $1.30 |
| Output | $4.45 | $1.50 (best) | $2.61 |
| Cached input | $0.178 | $0.025 | $0.011 (best) |
| Blended (3:1) | $1.78 | $0.563 (best) | $1.63 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Volcengine Ark API | Official Google API | Official Xiaomi API |
| Limits | |||
| Context window | 256,000 tokens | 1,048,576 tokens (best) | 1,048,576 tokens (best) |
| Max output | 256,000 tokens (best) | 65,536 tokens | 131,072 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | No |
| PDFs | No | Yes | No |
| Audio | No | Yes | No |
| Video | Yes | Yes | No |
| Reasoning | Yesminimal · low · medium · high · xhigh · max | Yesminimal · low · medium · high | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | No |
| Availability | |||
| Weights | Proprietary | Proprietary | Open |
| API model ID | doubao-seed-2-1-pro-260628 | gemini-3.1-flash-lite | mimo-v2.5-pro-ultraspeed |
| API providers | 2 | 23 (best) | 1 |
| Released | Jun 23, 2026 | May 7, 2026 | Jun 8, 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.
- Seed 2.1 Pro$17.81
- Gemini 3.1 Flash Lite$5.50
- MiMo-V2.5-Pro-UltraSpeed$18.27
Which should you choose?
Which is better: Seed 2.1 Pro, Gemini 3.1 Flash Lite or MiMo-V2.5-Pro-UltraSpeed?
Gemini 3.1 Flash Lite is the better all-round choice, scoring 73/100 against Seed 2.1 Pro (50) and MiMo-V2.5-Pro-UltraSpeed (43). It leads on price and inputs & features. 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, Seed 2.1 Pro, Gemini 3.1 Flash Lite or MiMo-V2.5-Pro-UltraSpeed?
Gemini 3.1 Flash Lite is cheaper at $0.25 input / $1.50 output per million tokens (official Google API price). MiMo-V2.5-Pro-UltraSpeed costs $1.30 input / $2.61 output per million tokens (official Xiaomi API price); Seed 2.1 Pro costs $0.891 input / $4.45 output per million tokens (official Volcengine Ark API price). At a typical mix of three input tokens to one output token, that is $0.563 per million tokens for Gemini 3.1 Flash Lite versus $1.63 for MiMo-V2.5-Pro-UltraSpeed (2.9× as much) and $1.78 for Seed 2.1 Pro (3.2× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Seed 2.1 Pro has not been scored yet, Gemini 3.1 Flash Lite has not been scored yet and MiMo-V2.5-Pro-UltraSpeed has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Seed 2.1 Pro, Gemini 3.1 Flash Lite and MiMo-V2.5-Pro-UltraSpeed 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?
Gemini 3.1 Flash Lite and MiMo-V2.5-Pro-UltraSpeed have the largest context windows (1,048,576 and 1,048,576 tokens), against 256,000 for Seed 2.1 Pro. Maximum output per response: Seed 2.1 Pro up to 256,000, Gemini 3.1 Flash Lite up to 65,536, MiMo-V2.5-Pro-UltraSpeed up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Seed 2.1 Pro accepts text, images and video; Gemini 3.1 Flash Lite accepts text, images, PDFs, audio and video; MiMo-V2.5-Pro-UltraSpeed accepts text. Gemini 3.1 Flash Lite 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; Seed 2.1 Pro and Gemini 3.1 Flash Lite is proprietary.
Which is newer?
Seed 2.1 Pro is the newest, released Jun 23, 2026. MiMo-V2.5-Pro-UltraSpeed came out Jun 8, 2026; Gemini 3.1 Flash Lite came out May 7, 2026. Knowledge cutoff: Gemini 3.1 Flash Lite Jan 2025, 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.
