Solar Pro 2

Solar Pro 2 is Upstage's July 2025 flagship: a 31B-parameter model with a hybrid architecture offering Chat Mode for fast responses and Reasoning Mode for structured multi-step thinking. It became Korea's first globally recognized frontier model by scoring 58 on the Artificial Analysis Intelligence Index — five points above GPT-4.1 and ahead of Mistral Small, Llama 4 Maverick, and DeepSeek V3 — while Upstage claims it was trained on a tenth of the chip budget of rivals. It carries a 65K context window, tool calling, and strong Korean fluency with cultural awareness for finance, legal, and medical domains.

The honest picture: it's a closed, API-only model — no open weights, so no self-hosting or fine-tuning. The 'tenth of the chips' efficiency claim is Upstage's own framing and hard to verify independently. Outside Korean-language and document-heavy enterprise niches its ecosystem is small, and Artificial Analysis scores, while credible, are one lens among many.