Z.ai: GLM 5.1
Nothing here. The model returned empty. We stared at it for a while.
Z.ai: GLM 5.1 vs GPT-5 Codex
Compare Z.ai: GLM 5.1 by Z-ai against GPT-5 Codex by OpenAI, tested across 48 shared challenges. Updated April 2026.
Which is better, Z.ai: GLM 5.1 or GPT-5 Codex?
Z.ai: GLM 5.1 and GPT-5 Codex are both competitive models. Compare their real outputs side by side below.
Key Differences Between Z.ai: GLM 5.1 and GPT-5 Codex
Z.ai: GLM 5.1 is made by z-ai while GPT-5 Codex is from openai.
Our Verdict
GPT-5 Codex
Z.ai: GLM 5.1Runner-up
No community votes yet. On paper, GPT-5 Codex has the edge — bigger model tier, major provider backing.
Too close to call
Writing DNA
Style Comparison
Similarity
98%
GPT-5 Codex uses 14.6x more emoji
Z.ai: GLM 5.1
GPT-5 Codex
54%Vocabulary64%
18wSentence Length17w
0.31Hedging0.38
3.6Bold2.3
2.6Lists3.5
0.00Emoji0.15
0.43Headings0.49
0.11Transitions0.05
Based on 27 + 13 text responses
vsAsk them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
Model Similarity Index
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
Devstral M / S
95.7%
Qwen3 Coder / Flash
95.6%
GPT-5.4 / Mini
93.3%
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
Free preview13 of 58 slides
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