by UpstageReleased 27 January 2026
Upstage's Solar Pro 3, a 102B mixture-of-experts running 12B per pass, tuned first for Korean with English and Japanese support, able to reason, call tools and return structured output
Reads about 130 pages · writes up to 110 pages
Standard OpenAI fields, grouped by what they control. Anything not listed is accepted and ignored.
Shaping the reply
How long, how varied, where to stop.
max_tokenstemperaturetop_pfrequency_penaltypresence_penaltyReasoning
Let it think before answering — and see the thinking.
reasoningreasoning_effortinclude_reasoningStructured output
Get JSON you can parse instead of prose.
response_formatstructured_outputsTools
Let the model call your functions.
toolstool_choiceparallel_tool_callsNo. Upstage has retired it. Other Upstage models are on sale.
Upstage's Solar Pro 3, a 102B mixture-of-experts running 12B per pass, tuned first for Korean with English and Japanese support, able to reason, call tools and return structured output.
Upstage names Korean, English and Japanese. Arabic, French and Darja are not named.
It reads text. Up to 131K tokens in one request, about 130 pages. It writes up to 88 000 words at once.
No. Upstage has not published its weights.
Upstage. Released 27 January 2026.
Solar Decide does not write text. You describe a situation, ask typed questions, and it answers with one pick from your options, a number, or a yes or no, each with a probability. A whole document of about 500 pages can serve as the situation, and the Korean it understands is strong, which helps in routing, sorting and policy checks. Solar Decide Flash is the faster variant.
Solar Decide Flash does not write text. You describe a situation, ask typed questions, and it answers with one pick from your options, a number, or a yes or no, each with a probability. It is tuned for fast, even response times in routing, sorting and policy checks, and a document of about 500 pages can serve as the situation. Solar Decide is the standard version when speed matters less.
Solar Mini 4 reads text and writes text, keeping about 520 pages in mind at once. It is Upstage's compact, low-cost model for jobs where quick answers matter, such as work using the tools you connect to it. It is fluent in Korean, strong in English and Japanese, and copes with long material.
Upstage's Solar Pro 4, a large model with a 524K context for long-horizon tasks and agent workflows, strong in office productivity, document-heavy work and coding, above Solar Mini 4
From what its maker and two benchmark sites publish, and where it stands on OpenDunes. Read 29 Oct 2026.
Thinks first
Works through the problem before it answers.
Uses your tools
Can call functions your code provides.
Fills your JSON
Answers in the JSON shape you give it.
Searches the web No.
Can look things up online while it answers.
Cheaper on repeats
A prompt it saw a moment ago costs less the second time.
Answer customer questions in Korean or English
Run an agent with your tools
Uses your tools
Reason through a policy question
Thinks first