Z.ai: GLM 5 vs GPT-5 Codex

Compare Z.ai: GLM 5 by Zhipu AI against GPT-5 Codex by OpenAI, tested across 49 shared challenges. Updated April 2026.

Which is better, Z.ai: GLM 5 or GPT-5 Codex?

Z.ai: GLM 5 and GPT-5 Codex are both competitive models. Compare their real outputs side by side below.

Key Differences Between Z.ai: GLM 5 and GPT-5 Codex

Z.ai: GLM 5 is made by zhipu while GPT-5 Codex is from openai.

Our Verdict
Z.ai: GLM 5
Z.ai: GLM 5
GPT-5 Codex
GPT-5 Codex

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call
Writing DNA

Style Comparison

Similarity
99%

GPT-5 Codex uses 14.6x more emoji

Z.ai: GLM 5
GPT-5 Codex
54%Vocabulary64%
17wSentence Length17w
0.37Hedging0.38
6.3Bold2.3
4.7Lists3.5
0.00Emoji0.15
0.60Headings0.49
0.18Transitions0.05
Based on 22 + 13 text responses
vs

Ask them anything yourself

Z.ai: GLM 5GPT-5 Codex

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.

AI Hallucination Index 2026
Free preview13 of 58 slides
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