GPT-5.6 Luna ProvsHy4 Preview
Hy4 Preview is cheaper than GPT-5.6 Luna Pro at $0.834/M vs $1/M input tokens.
| Spec | GPT-5.6 Luna Pro | Hy4 Preview |
|---|---|---|
| Input price | $1/M tokens | $0.834/M tokens |
| Output price | $6/M tokens | $2.501/M tokens |
| Context window | 1.1M tokens | 1.0M tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | Jul 2026 | Aug 2026 |
Our Verdict
Hy4 Preview
GPT-5.6 Luna ProRunner-up
Not enough votes to call it. On the specs, Hy4 Preview has the edge: bigger model tier, newer.
Too close to call
API pricing
Cost per 1M tokens
GPT-5.6 Luna Pro
Input
$1.00
Output
$6.00
Hy4 Preview
Input
$0.83
1.2× cheaper
Output
$2.50
2.4× cheaper
Hy4 Preview is cheaper on both: 1.2× input, 2.4× output.
Where to run it
3 hosts, cheapest first
GPT-5.6 Luna Pro2 hosts
Hy4 Preview1 host
Per million tokens. Prices and uptime via OpenRouter, checked 9 Sep 2026.
Writing DNA
Style Comparison
Similarity
43%
Hy4 Preview uses 2.1x more bold
GPT-5.6 Luna Pro
Hy4 Preview
58%Vocabulary53%
18wSentence Length16w
0.81Hedging0.43
2.9Bold5.9
5.1Lists3.8
0.54Emoji0.40
1.10Headings0.67
0.09Transitions0.13
Based on 27 + 27 text responses
Research
What we learned reading every model
FAQ
Common questions
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