GPT-5.3-Codex vs MoonshotAI: Kimi K3
Compare GPT-5.3-Codex by OpenAI against MoonshotAI: Kimi K3 by Moonshot AI, context windows of 400K vs 1.0M, tested across 53 shared challenges.
Our Verdict
GPT-5.3-Codex
MoonshotAI: Kimi K3
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
API pricing
Cost per 1M tokens
GPT-5.3-Codex
Input
$1.75
1.7× cheaper
Output
$14.00
1.1× cheaper
MoonshotAI: Kimi K3
Input
$3.00
Output
$15.00
GPT-5.3-Codex is cheaper on both — 1.7× input, 1.1× output
Writing DNA
Style Comparison
Similarity
37%
MoonshotAI: Kimi K3 uses 6.1x more transitions
GPT-5.3-Codex
MoonshotAI: Kimi K3
65%Vocabulary58%
23wSentence Length21w
0.51Hedging0.46
6.5Bold3.6
6.2Lists3.4
0.16Emoji0.78
1.90Headings0.89
0.03Transitions0.17
Based on 23 + 27 text responses
Research
What we learned reading every model
FAQ
