Z.ai: GLM 5.1 vs GPT-4.1 Mini

Compare Z.ai: GLM 5.1 by Z-ai against GPT-4.1 Mini by OpenAI, context windows of 203K vs 1.0M, tested across 52 shared challenges. Updated April 2026.

Which is better, Z.ai: GLM 5.1 or GPT-4.1 Mini?

Z.ai: GLM 5.1 and GPT-4.1 Mini are both competitive models. Z.ai: GLM 5.1 costs $1.4/M input tokens vs $0.4/M for GPT-4.1 Mini. Context windows: 203K vs 1048K tokens. Compare their real outputs side by side below.

Key Differences Between Z.ai: GLM 5.1 and GPT-4.1 Mini

Z.ai: GLM 5.1 is made by z-ai while GPT-4.1 Mini is from openai. Z.ai: GLM 5.1 has a 203K token context window compared to GPT-4.1 Mini's 1048K. On pricing, Z.ai: GLM 5.1 costs $1.4/M input tokens vs $0.4/M for GPT-4.1 Mini.

Our Verdict
Z.ai: GLM 5.1
Z.ai: GLM 5.1
GPT-4.1 Mini
GPT-4.1 Mini

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-4.1 Mini uses 1.9x more lists

Z.ai: GLM 5.1
GPT-4.1 Mini
54%Vocabulary59%
18wSentence Length19w
0.31Hedging0.46
3.6Bold4.7
2.6Lists4.9
0.00Emoji0.00
0.43Headings0.76
0.11Transitions0.17
Based on 27 + 23 text responses
vs

Ask them anything yourself

Z.ai: GLM 5.1GPT-4.1 Mini

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
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