Solar Pro 4
Upstage's closed commercial flagship LLM built for reliable production agents.
About
Solar Pro 4 is Upstage's fourth-generation Solar Pro flagship, released in August 2026. It is a closed commercial model engineered around behavioral reliability for enterprise agents: instruction following that holds across turns, tool-call structure that stays intact, and agents that act within policy and valid schema.
On release it became the first Korean model officially listed on OpenRouter and the Hermes Agent platform, and the first Korean model to enter the Agent Arena leaderboard. Upstage reported over 80 billion tokens of consumption within three days of its OpenRouter listing, and an Artificial Analysis Intelligence Index score of 42.
Specs
Context window
Pricing
Free quota
API access
Weights
Released
Benchmarks
Provider-reported unless a source says otherwise. Benchmarks are marketing-adjacent by nature — treat them as directional.
Use cases
Trust score — 9/10
Scored 9/10 (verified tier, metrics-v1). Evidence: Verified via vendor site/docs/GitHub and reputable coverage, wave 110; Trending score 86/100 from researcher assessment.