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GLM-5.3 vs Seed 2.1 Pro

GLM-5.3 shows notably better performance in the majority of benchmarks.

Zhipu AI · ByteDance · Updated for 2026

Which is better?

GLM-5.3 outperforms in 6 benchmarks (CyberGym, Humanity's Last Exam, NL2Repo, PostTrainBench, Terminal-Bench 2.1, Toolathlon), while Seed 2.1 Pro is better at 2 benchmarks (Agents' Last Exam, Program Bench). GLM-5.3 shows notably better performance in the majority of benchmarks.

Based on current benchmark, pricing, and model metadata for 2026.

Choose GLM-5.3

  • you want the strongest raw capability — it leads on 6 of 8 shared benchmarks
  • you want the most recent training data — it shipped Aug 2026

Choose Seed 2.1 Pro

  • you are already invested in the ByteDance ecosystem

At a glance

The differences that matter most.

GLM-5.3
Zhipu AI
Seed 2.1 Pro
ByteDance
Benchmark wins
6 of 8
2 of 8
Input price
$1.40 / M
— / M
Output price
$4.40 / M
— / M
Context window
1,000,000
—
Released
Aug 2026
Jun 2026
License
Unknown
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

8 benchmarks

GLM-5.3 outperforms in 6 benchmarks (CyberGym, Humanity's Last Exam, NL2Repo, PostTrainBench, Terminal-Bench 2.1, Toolathlon), while Seed 2.1 Pro is better at 2 benchmarks (Agents' Last Exam, Program Bench).

GLM-5.3 shows notably better performance in the majority of benchmarks.

Mon Aug 24 2026 • llm-stats.com

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only GLM-5.3 specifies input context (1,000,000 tokens). Only GLM-5.3 specifies output context (128,000 tokens).

Zhipu AI
GLM-5.3
Input1,000,000 tokens
Output128,000 tokens
ByteDance
Seed 2.1 Pro
Input- tokens
Output- tokens
Mon Aug 24 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Seed 2.1 Pro supports multimodal inputs, whereas GLM-5.3 does not.

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

GLM-5.3

Text
Images
Audio
Video

Seed 2.1 Pro

Text
Images
Audio
Video

Release Timeline

When each model was launched

GLM-5.3 was released on 2026-08-14, while Seed 2.1 Pro was released on 2026-06-24.

GLM-5.3 is 2 months newer than Seed 2.1 Pro.

GLM-5.3

Aug 14, 2026

1 weeks ago

1mo 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 GLM-5.3 and Seed 2.1 Pro side-by-side, then vote on the output you prefer.

GLM-5.3
✓ Preferred
Seed 2.1 Pro
Open in Playground

FAQ

Common questions about GLM-5.3 vs Seed 2.1 Pro.

Which is better, GLM-5.3 or Seed 2.1 Pro?

GLM-5.3 shows notably better performance in the majority of benchmarks. GLM-5.3 is made by Zhipu AI and Seed 2.1 Pro is made by ByteDance. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GLM-5.3 compare to Seed 2.1 Pro in benchmarks?

GLM-5.3 scores Terminal-Bench 2.1: 88.2%, CyberGym: 84.5%, FrontierSWE: 78.1%, Toolathlon: 73.0%, DeepSWE 1.1: 66.9%. 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 context window sizes for GLM-5.3 and Seed 2.1 Pro?

GLM-5.3 supports 1.0M tokens and Seed 2.1 Pro supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GLM-5.3 and Seed 2.1 Pro?

Key differences include multimodal support (no vs yes), licensing (Unknown vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes GLM-5.3 and Seed 2.1 Pro?

GLM-5.3 is developed by Zhipu AI and Seed 2.1 Pro is developed by ByteDance.

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