GPT-5.3-Codex vs Kimi K2
Compare GPT-5.3-Codex by OpenAI against Kimi K2 by Moonshot AI, tested across 53 shared challenges.
Our Verdict
GPT-5.3-Codex
Kimi K2Runner-up
No community votes yet. On paper, GPT-5.3-Codex has the edge — newer, bigger context window, major provider backing.
Kimi K2 is 6.1x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
GPT-5.3-Codex
Input
$1.75
Output
$14.00
Kimi K2
Input
$0.57
3.1× cheaper
Output
$2.30
6.1× cheaper
Kimi K2 is cheaper on both — 3.1× input, 6.1× output
Writing DNA
Style Comparison
Similarity
57%
Kimi K2 uses 4.3x more emoji
GPT-5.3-Codex
Kimi K2
65%Vocabulary63%
23wSentence Length19w
0.51Hedging0.35
6.5Bold4.2
6.2Lists3.6
0.16Emoji0.68
1.90Headings0.61
0.03Transitions0.06
Based on 23 + 22 text responses
Research
What we learned reading every model
FAQ
Common questions
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