Z.ai: GLM 5.1 vs OpenAI: GPT-5.6 Terra
Compare Z.ai: GLM 5.1 by Z-ai against OpenAI: GPT-5.6 Terra by OpenAI, context windows of 203K vs 1.1M, tested across 53 shared challenges.
Our Verdict
OpenAI: GPT-5.6 Terra
Z.ai: GLM 5.1Runner-up
No community votes yet. On paper, OpenAI: GPT-5.6 Terra has the edge — newer, bigger context window, major provider backing.
Z.ai: GLM 5.1 is 3.4x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Z.ai: GLM 5.1
Input
$1.40
1.8× cheaper
Output
$4.40
3.4× cheaper
OpenAI: GPT-5.6 Terra
Input
$2.50
Output
$15.00
Z.ai: GLM 5.1 is cheaper on both — 1.8× input, 3.4× output
Writing DNA
Style Comparison
Similarity
33%
OpenAI: GPT-5.6 Terra uses 2.8x more hedging
Z.ai: GLM 5.1
OpenAI: GPT-5.6 Terra
54%Vocabulary57%
18wSentence Length18w
0.31Hedging0.85
3.6Bold2.8
2.6Lists4.6
0.00Emoji0.00
0.43Headings1.12
0.11Transitions0.06
Based on 27 + 27 text responses
Research
What we learned reading every model
FAQ
Common questions
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