GPT-5.1-Codex vs Kimi K2 Thinking
Compare GPT-5.1-Codex by OpenAI against Kimi K2 Thinking by Moonshot AI, in 7 community votes, kimi k2 thinking wins 67% of head-to-head duels, context windows of 400K vs 262K, tested across 52 shared challenges. Updated April 2026.
Which is better, GPT-5.1-Codex or Kimi K2 Thinking?
Kimi K2 Thinking is the better choice overall, winning 67% of 7 blind community votes on Rival. GPT-5.1-Codex costs $1.25/M input tokens vs $0.6/M for Kimi K2 Thinking. Context windows: 400K vs 262K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.1-Codex and Kimi K2 Thinking
GPT-5.1-Codex is made by openai while Kimi K2 Thinking is from moonshotai. GPT-5.1-Codex has a 400K token context window compared to Kimi K2 Thinking's 262K. On pricing, GPT-5.1-Codex costs $1.25/M input tokens vs $0.6/M for Kimi K2 Thinking. In community voting, In 7 community votes, Kimi K2 Thinking wins 67% of head-to-head duels.
In 7 community votes, Kimi K2 Thinking wins 67% of head-to-head duels. GPT-5.1-Codex leads in Web Design. Based on blind community voting from the Rival open dataset of 7+ human preference judgments for this pair.
Pick Kimi K2 Thinking. In 7 blind votes, Kimi K2 Thinking wins 67% of the time. That's not luck.
GPT-5.1-Codex particularly excels in Web Design. Kimi K2 Thinking is 4.0x cheaper per token — worth considering if cost matters.
Style Comparison
GPT-5.1-Codex uses 6.8x more transitions
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178 models fingerprinted across 32 writing dimensions. Free research.
185x
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We read every word. 250 models. 2.14 million words. This is what we found.
