GPT-5 CodexvsMercury 2.5 Preview
Mercury 2.5 Preview is the newer model, released after GPT-5 Codex.
| Spec | GPT-5 Codex | Mercury 2.5 Preview |
|---|---|---|
| Input price | — | $0.04/M tokens |
| Output price | — | $0.15/M tokens |
| Context window | — | 260K tokens |
| Free API (OpenRouter) | No | No |
| Released | Sep 2025 | Aug 2026 |
Our Verdict
GPT-5 Codex
Mercury 2.5 PreviewRunner-up
Not enough votes to call it. On the specs, GPT-5 Codex has the edge: bigger model tier, major provider backing.
Too close to call
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
GPT-5 Codex
Input
—
Output
—
Mercury 2.5 Preview
Input
$0.04
Output
$0.15
Where to run it
1 host
GPT-5 Codex
No hosts listed on OpenRouter.
Mercury 2.5 Preview1 host
Per million tokens. Prices and uptime via OpenRouter, checked 12 Sep 2026.
Writing DNA
Style Comparison
Similarity
51%
GPT-5 Codex uses 14.6x more emoji
GPT-5 Codex
Mercury 2.5 Preview
64%Vocabulary65%
17wSentence Length14w
0.38Hedging0.44
2.3Bold4.9
3.5Lists3.3
0.15Emoji0.00
0.49Headings0.79
0.05Transitions0.20
Based on 13 + 26 text responses
Research
What we learned reading every model
FAQ
Common questions
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