Solar Pro 4
Solar Pro 4
Upstage's closed flagship: half a million tokens of context at a budget price.
Updated
The read
Solar Pro 4 is Upstage's hosted flagship, released in August with a 512,000-token window and a price of thirty cents in and $1.20 out per million tokens. It scores well above most small models on the independent index and is particularly strong at reading long documents. Korean and English remain its best languages, and outside Korea the surrounding ecosystem is thin. Its open sibling, Solar Open 2, is the one to choose if you need the weights.
Where it shines
- 512,000-token context at a low price
- Strong long-document reading for its price band
- Among the best models for Korean
Worth knowing first
- Closed weights, unlike its Solar Open sibling
- Thin tooling and community outside Korea
Index score
78.2
Provisional. This score is read from the product's public capability, not from the one-prompt rebuild the fully reviewed entries went through, so treat it as a placing rather than a verdict.
- Rank
- 48 of 73
- Builds
- LLMs
- Category
- Frontier
- Output
- Text in, text out over an API
- Pricing
- Paid only
- Best for
- Long-document work in Korean and English on a budget
Scores are our own editorial judgement, weighted craft 55, speed 10, control 15 and value 20.
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