GPT-5.3-Codex vs Grok 3
Compare GPT-5.3-Codex by OpenAI against Grok 3 by xAI, context windows of 400K vs 128K, tested across 52 shared challenges. Updated May 2026.
Which is better, GPT-5.3-Codex or Grok 3?
GPT-5.3-Codex and Grok 3 are both competitive models. Context windows: 400K vs 128K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.3-Codex and Grok 3
GPT-5.3-Codex is made by openai while Grok 3 is from xai. GPT-5.3-Codex has a 400K token context window compared to Grok 3's 128K.
API pricing
Per 1M tokens
GPT-5.3-Codex
Input
$1.75
Output
$14.00
Grok 3
Input
—
Output
—
Our Verdict
GPT-5.3-Codex
Grok 3Runner-up
No community votes yet. On paper, GPT-5.3-Codex has the edge — newer, bigger context window.
Too close to call
Writing DNA
Style Comparison
Similarity
43%
GPT-5.3-Codex uses 4.0x more emoji
GPT-5.3-Codex
Grok 3
65%Vocabulary49%
23wSentence Length18w
0.51Hedging0.94
6.5Bold2.5
6.2Lists3.0
0.16Emoji0.04
1.90Headings0.65
0.03Transitions0.08
Based on 23 + 17 text responses
FAQ
