GPT-5 CodexvsMercury
GPT-5 Codex is the newer model, released after Mercury.
| Spec | GPT-5 Codex | Mercury |
|---|---|---|
| Input price | — | $10/M tokens |
| Output price | — | $10/M tokens |
| Context window | — | 32K tokens |
| Free API (OpenRouter) | No | No |
| Released | Sep 2025 | Jun 2025 |
Our Verdict
GPT-5 Codex
MercuryRunner-up
Not enough votes to call it. On the specs, GPT-5 Codex has the edge: bigger model tier, newer, major provider backing.
GPT-5 Codex wins Image Generation and Web Design.
Slight edge
API pricing
Cost per 1M tokens
GPT-5 Codex
Input
—
Output
—
Mercury
Input
$10.00
Output
$10.00
Writing DNA
Style Comparison
Similarity
53%
GPT-5 Codex uses 5.2x more emoji
GPT-5 Codex
Mercury
64%Vocabulary60%
17wSentence Length31w
0.38Hedging0.78
2.3Bold4.1
3.5Lists2.8
0.15Emoji0.03
0.49Headings0.88
0.05Transitions0.06
Based on 13 + 26 text responses
Research
What we learned reading every model
FAQ
Common questions
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