Z.AI: GLM 4.5 vs xAI: Grok 4 Fast (free)
Compare Z.AI: GLM 4.5 by Zhipu AI against xAI: Grok 4 Fast (free) by xAI, in 5 community votes, xai: grok 4 fast (free) wins 80% of head-to-head duels, context windows of 128K vs 2.0M, tested across 35 shared challenges. Updated April 2026.
Which is better, Z.AI: GLM 4.5 or xAI: Grok 4 Fast (free)?
xAI: Grok 4 Fast (free) is the better choice overall, winning 80% of 5 blind community votes on Rival. Z.AI: GLM 4.5 costs $0.6/M input tokens vs $0/M for xAI: Grok 4 Fast (free). Context windows: 128K vs 2000K tokens. Compare their real outputs side by side below.
Key Differences Between Z.AI: GLM 4.5 and xAI: Grok 4 Fast (free)
Z.AI: GLM 4.5 is made by zhipu while xAI: Grok 4 Fast (free) is from xai. Z.AI: GLM 4.5 has a 128K token context window compared to xAI: Grok 4 Fast (free)'s 2000K. On pricing, Z.AI: GLM 4.5 costs $0.6/M input tokens vs $0/M for xAI: Grok 4 Fast (free). In community voting, In 5 community votes, xAI: Grok 4 Fast (free) wins 80% of head-to-head duels.
In 5 community votes, xAI: Grok 4 Fast (free) wins 80% of head-to-head duels. xAI: Grok 4 Fast (free) leads in Web Design. Based on blind community voting from the Rival open dataset of 5+ human preference judgments for this pair.
Pick xAI: Grok 4 Fast (free). In 5 blind votes, xAI: Grok 4 Fast (free) wins 80% of the time. That's not luck.
xAI: Grok 4 Fast (free) particularly excels in Web Design.
Style Comparison
Z.AI: GLM 4.5 uses 13.1x more emoji
vs
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Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
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12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
