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Hy4 preview vs Seed 2.1 Pro

Hy4 preview leads the LLM Stats Score 51.3 to 46.6.

Tencent · ByteDance · Updated for 2026

Which is better?

Hy4 preview leads the overall LLM Stats Score 51.3 to 46.6, ranking #13 overall.

In the 17 individual benchmarks reported for both models, Hy4 preview wins 12; this is a narrower head-to-head signal than the composite indexes.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Hy4 preview

  • overall performance matters — it scores 51.3 and ranks #13 on LLM Stats
  • your work emphasizes agents — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 12 of 17 exact shared results
  • you want the most recent training data — it shipped Aug 2026
  • you need open weights you can self-host or fine-tune

Choose Seed 2.1 Pro

  • you are already invested in the ByteDance ecosystem

At a glance

The differences that matter most.

Hy4 preview
Tencent
Seed 2.1 Pro
ByteDance
Core performance indexes
LLM Stats Score
51.3
#13
46.6
#24
Reasoning
51.0
#10
47.5
#21
Coding
39.9
#11
33.8
#30
Agents
36.7
#13
31.6
#25
Cost, coverage & limits
Benchmark wins
12 of 17
5 of 17
Input price
— / M
— / M
Output price
— / M
— / M
Context window
—
—

Capability indexes

Additional strengths measured across groups of related public benchmarks

2 shared
Index
Hy4 preview
Seed 2.1 Pro
Math
40.2#14
39.2#20
Tool use
31.4#10
26.5#26
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

32 reported for Hy4 preview · 94 for Seed 2.1 Pro

17 shared

Hy4 preview outperforms in 12 benchmarks (APEX-Agents, CyberGym, DeepSWE, HorizonMath, MathArena Apex, NL2Repo, PostTrainBench, SuperChem, SWE-Bench Pro, Terminal-Bench 2.1, Toolathlon, Workspace Bench), while Seed 2.1 Pro is better at 5 benchmarks (Agents' Last Exam, MCP Atlas, OfficeQA Pro, OneMillion Bench, Program Bench).

Hy4 preview shows notably better performance in the majority of benchmarks.

Thu Sep 03 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Input capabilities

Documented input modalities across available providers

Seed 2.1 Pro supports multimodal inputs, whereas Hy4 preview does not.

Seed 2.1 Pro can handle both text and other forms of data like images, making it suitable for multimodal applications.

Hy4 preview

Text
Images
Audio
Video

Seed 2.1 Pro

Text
Images
Audio
Video

License

Usage and distribution terms

Hy4 preview is licensed under Apache 2.0, while Seed 2.1 Pro uses a proprietary license.

License differences may affect how you can use these models in commercial or open-source projects.

Hy4 preview

Apache 2.0

Open weights

Seed 2.1 Pro

Proprietary

Closed source

Release Timeline

When each model was launched

Hy4 preview was released on 2026-08-28, while Seed 2.1 Pro was released on 2026-06-24.

Hy4 preview is 2 months newer than Seed 2.1 Pro.

Hy4 preview

Aug 28, 2026

5 days ago

2mo newer
Seed 2.1 Pro

Jun 24, 2026

2 months ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Hy4 preview and Seed 2.1 Pro side-by-side, then vote on the output you prefer.

Hy4 preview
✓ Preferred
Seed 2.1 Pro
Open in Playground

FAQ

Common questions about Hy4 preview vs Seed 2.1 Pro.

Which is better, Hy4 preview or Seed 2.1 Pro?

Hy4 preview leads the LLM Stats Score 51.3 to 46.6. Hy4 preview is made by Tencent and Seed 2.1 Pro is made by ByteDance. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Hy4 preview compare to Seed 2.1 Pro in benchmarks?

Hy4 preview scores GPQA: 92.3%, Terminal-Bench 2.1: 85.4%, WideSearch: 83.9%, MCP Atlas: 83.7%, SWE-bench Multilingual: 82.9%. Seed 2.1 Pro scores CharXiv-D: 95.5%, MathVision: 94.5%, MathVista: 90.7%, MathVerse: 89.7%, Video-MME: 89.2%.

What are the main differences between Hy4 preview and Seed 2.1 Pro?

Key differences include LLM Stats Score (51.3 vs 46.6), multimodal support (no vs yes), licensing (Apache 2.0 vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes Hy4 preview and Seed 2.1 Pro?

Hy4 preview is developed by Tencent and Seed 2.1 Pro is developed by ByteDance.

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