Seed Character vs Viv Fast
Too close to call on our weighted score (Seed Character 75, Viv Fast 75). The right pick depends on what you value most.
ByteDance SeedSeed Character
75/100- ECI—
- Price$0.119 / $0.297
- Context256K
VivgridViv Fast
75/100- ECI—
- Price$0.13 / $0.40
- Context1M
Add a model
Make it a three-way comparison.
Too close to call
It is close. Our weighted score puts them within a point (Seed Character 75/100, Viv Fast 75/100), so choose by what matters most for your work: Seed Character on price and Viv Fast 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 CharacterSeed Character $0.163 · Viv Fast $0.198 per 1M tokens (3:1 blend)
- Longest contextViv FastViv Fast 1,000,000 · Seed Character 256,000 tokens
- Widest inputsSeed CharacterSeed Character: Text, Images, Video · Viv Fast: Text, Images
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Seed Character | Viv Fast |
|---|---|---|---|
| Price | 50% | 87 | 83 |
| Inputs & features | 30% | 80 | 70 |
| Context window | 20% | 36 | 60 |
| Overall | 100% | 75/100 | 75/100 |
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 CharacterByteDance Seed | Viv FastVivgrid |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.119 (best) | $0.13 |
| Output | $0.297 (best) | $0.40 |
| Cached input | $0.024 (best) | $0.05 |
| Blended (3:1) | $0.163 (best) | $0.198 |
| Long-context rate | Over 32K: $0.178 / $0.891 | Same rate |
| Price source | Official Volcengine Ark API | Official Vivgrid API |
| Limits | ||
| Context window | 256,000 tokens | 1,000,000 tokens (best) |
| Max output | 256,000 tokens | 256,000 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | No |
| Audio | No | No |
| Video | Yes | No |
| Reasoning | Yesminimal · low · high | Yeslow · high · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | doubao-seed-character-260628 | viv-fast |
| API providers | 2 (best) | 1 |
| Released | Jun 23, 2026 | Sep 21, 2026 |
| Knowledge cutoff | — | Sep 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Seed Character$1.78
- Viv Fast$2.10
Which should you choose?
Which is better: Seed Character or Viv Fast?
It is close. Our weighted score puts them within a point (Seed Character 75/100, Viv Fast 75/100), so choose by what matters most for your work: Seed Character on price and Viv Fast 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, Seed Character or Viv Fast?
Seed Character is cheaper at $0.119 input / $0.297 output per million tokens (official Volcengine Ark API price). Viv Fast costs $0.13 input / $0.40 output per million tokens (official Vivgrid API price). At a typical mix of three input tokens to one output token, that is $0.163 per million tokens for Seed Character versus $0.198 for Viv Fast (1.2× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Seed Character has not been scored yet and Viv Fast has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Seed Character and Viv Fast 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?
Viv Fast has the largest context window at 1,000,000 tokens, against 256,000 for Seed Character. Maximum output per response: Seed Character up to 256,000, Viv Fast up to 256,000 tokens.
Which can read images, PDFs, audio or video?
Seed Character accepts text, images and video; Viv Fast accepts text and images. Seed Character handles the widest range of inputs.
Are any of these open source?
No. Seed Character and Viv Fast are proprietary and only available through APIs and apps.
Which is newer?
Viv Fast is the newest, released Sep 21, 2026. Seed Character came out Jun 23, 2026. Knowledge cutoff: Viv Fast Sep 2026.
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.
