Hy4 preview vs LongCat-2.5-Preview vs Seed 2.1 Turbo
Seed 2.1 Turbo comes out ahead, 57 to 52 and 45 on our weighted score, and it is the cheaper option too.
TencentHy4 preview
45/100- ECI—
- Price$0.834 / $2.50
- Context1.02M
Meituan (LongCat)LongCat-2.5-Preview
52/100- ECI—
- Price$0.75 / $2.95
- Context1M
- Our pick
ByteDance SeedSeed 2.1 Turbo
57/100- ECI—
- Price$0.445 / $2.23
- Context256K
Seed 2.1 Turbo is our pick
Seed 2.1 Turbo is the better all-round choice, scoring 57/100 against LongCat-2.5-Preview (52) and Hy4 preview (45). 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 priceSeed 2.1 TurboSeed 2.1 Turbo $0.891 · Hy4 preview $1.25 · LongCat-2.5-Preview $1.30 per 1M tokens (3:1 blend)
- Longest contextHy4 previewHy4 preview 1,024,000 · LongCat-2.5-Preview 1,000,000 · Seed 2.1 Turbo 256,000 tokens
- Widest inputsSeed 2.1 TurboHy4 preview: Text · LongCat-2.5-Preview: Text, Images · Seed 2.1 Turbo: Text, Images, Video
- Self-hostingHy4 previewPublishes downloadable weights
| Measure | Weight | Hy4 preview | LongCat-2.5-Preview | Seed 2.1 Turbo |
|---|---|---|---|---|
| Price | 50% | 45 | 44 | 52 |
| Inputs & features | 30% | 35 | 60 | 80 |
| Context window | 20% | 60 | 60 | 36 |
| Overall | 100% | 45/100 | 52/100 | 57/100 |
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 | Hy4 previewTencent | LongCat-2.5-PreviewMeituan (LongCat) | Seed 2.1 TurboByteDance Seed |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.834 | $0.75 | $0.445 (best) |
| Output | $2.50 | $2.95 | $2.23 (best) |
| Cached input | $0.042 (best) | — | $0.089 |
| Blended (3:1) | $1.25 | $1.30 | $0.891 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Tencent TokenHub API | Median of 1 providers | Official Volcengine Ark API |
| Limits | |||
| Context window | 1,024,000 tokens (best) | 1,000,000 tokens | 256,000 tokens |
| Max output | 64,000 tokens | 131,072 tokens | 256,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | No | No |
| Audio | No | No | No |
| Video | No | No | Yes |
| Reasoning | Yeshigh | Yes | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | No | No | Yes |
| Availability | |||
| Weights | Open | Proprietary | Proprietary |
| API model ID | hy4-preview | — | doubao-seed-2-1-turbo-260628 |
| API providers | 13 (best) | 2 | 4 |
| Released | Aug 28, 2026 | Sep 25, 2026 | Jun 23, 2026 |
| Knowledge cutoff | — | — | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Hy4 preview$13.34
- LongCat-2.5-Preview$13.40
- Seed 2.1 Turbo$8.91
Which should you choose?
Which is better: Hy4 preview, LongCat-2.5-Preview or Seed 2.1 Turbo?
Seed 2.1 Turbo is the better all-round choice, scoring 57/100 against LongCat-2.5-Preview (52) and Hy4 preview (45). 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, Hy4 preview, LongCat-2.5-Preview or Seed 2.1 Turbo?
Seed 2.1 Turbo is cheaper at $0.445 input / $2.23 output per million tokens (official Volcengine Ark API price). Hy4 preview costs $0.834 input / $2.50 output per million tokens (official Tencent TokenHub API price); LongCat-2.5-Preview costs $0.75 input / $2.95 output per million tokens (median across 1 API provider). At a typical mix of three input tokens to one output token, that is $0.891 per million tokens for Seed 2.1 Turbo versus $1.25 for Hy4 preview (1.4× as much) and $1.30 for LongCat-2.5-Preview (1.5× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Hy4 preview has not been scored yet, LongCat-2.5-Preview has not been scored yet and Seed 2.1 Turbo has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Hy4 preview, LongCat-2.5-Preview and Seed 2.1 Turbo 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?
Hy4 preview has the largest context window at 1,024,000 tokens, against 1,000,000 for LongCat-2.5-Preview and 256,000 for Seed 2.1 Turbo. Maximum output per response: Hy4 preview up to 64,000, LongCat-2.5-Preview up to 131,072, Seed 2.1 Turbo up to 256,000 tokens.
Which can read images, PDFs, audio or video?
Hy4 preview accepts text; LongCat-2.5-Preview accepts text and images; Seed 2.1 Turbo accepts text, images and video. Seed 2.1 Turbo handles the widest range of inputs.
Are any of these open source?
Hy4 preview publishes its weights and can be self-hosted; LongCat-2.5-Preview and Seed 2.1 Turbo is proprietary.
Which is newer?
LongCat-2.5-Preview is the newest, released Sep 25, 2026. Hy4 preview came out Aug 28, 2026; Seed 2.1 Turbo came out Jun 23, 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.
