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Solar Pro 4 Overview
Confirmed against Upstage documentation, August 2026
Solar Pro 4 is a chat-reasoning AI model created by Upstage, featuring undisclosed parameters and a context window of 524288.
Solar Pro 4 is a large language model from Upstage built for enterprise workflows, excelling at structured text understanding (HTML, Markdown), tool calling, and long-document reasoning. It features a large context window and strong multilingual support, particularly in Korean, Japanese, and English.
Model Lineage & Specification
upstage-solar-pro-4 is Upstage's primary release in the current family.
upstage-solar-pro-4Comparable models
| Feature | Solar Pro 4 | Qwen3.8 Max Preview | Nemotron 3 Ultra | Nemotron 3 Ultra 550B A55B |
|---|---|---|---|---|
| Description | Solar Pro 4 is a large language model from Upstage built for enterprise workflow... | Preview Qwen flagship for million-token multimodal reasoning and long-horizon ag... | NVIDIA Nemotron 3 Ultra is a flagship open-weight frontier LLM family engineered... | Largest Nemotron 3 model for maximum open-weight reasoning and agent accuracy... |
| API Identifier | upstage-solar-pro-4 | alibaba-qwen3.8-max-preview | nvidia-nemotron-3-ultra | nvidia-nemotron-3-ultra-550b-a55b |
| Parameters | — | — | 550B total / 55B active | 550B |
| Context Window | 524288 | 1M tokens | 1M tokens | 1M tokens |
| License / Type | api only | api only | open weights | open weights |
Solar Pro 4
Solar Pro 4 is a large language model from Upstage built for enterprise workflow...
upstage-solar-pro-4Qwen3.8 Max Preview
Preview Qwen flagship for million-token multimodal reasoning and long-horizon ag...
alibaba-qwen3.8-max-previewNemotron 3 Ultra
NVIDIA Nemotron 3 Ultra is a flagship open-weight frontier LLM family engineered...
nvidia-nemotron-3-ultraNemotron 3 Ultra 550B A55B
Largest Nemotron 3 model for maximum open-weight reasoning and agent accuracy...
nvidia-nemotron-3-ultra-550b-a55bSolar Pro 4 is a large language model from Upstage built for enterprise workflows, excelling at structured text understanding (HTML, Markdown), tool calling, and long-document reasoning. It features a large context window and strong multilingual support, particularly in Korean, Japanese, and English.