Solar Pro 4
Summary
Solar Pro 4 is a proprietary language model from Upstage, released on 6 Aug 2026. It accepts text and generates text, with a 524K-token context window and up to 131K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $0.09 per million input tokens and $0.36 per million output tokens (OpenRouter), across 2 providers we track.
Upstage's flagship model, specialized for agentic use
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | Upstage |
|---|---|
| Release date | 6 Aug 2026 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 524K (524,288 tokens) [models.dev] |
| Max output | 131K tokens [models.dev] |
| Knowledge cutoff | Feb 2026 [models.dev] |
| Input | Text [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
| Structured output | Yes [models.dev] |
Solar Pro 4 API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| OpenRouter upstage/solar-pro4 | $0.09 | $0.36 | $0.02 | 524K | OpenRouter, 4 Oct 2026 |
| Upstage Console solar-pro4 | $0.30 | $1.20 | $0.06 | 524K | models.dev, 4 Oct 2026 |
Frequently asked questions
What is the context window of Solar Pro 4?
Solar Pro 4 has a context window of 524,288 tokens (524K) and can generate up to 131,072 tokens in a single response, according to models.dev.
How much does the Solar Pro 4 API cost?
Through Upstage Console, Solar Pro 4 costs $0.30 per million input tokens and $1.20 per million output tokens. The lowest listed price is $0.09 input / $0.36 output through OpenRouter. Prices last verified 4 Oct 2026.
Is Solar Pro 4 open source?
No. Solar Pro 4 is a proprietary model; Upstage has not released its weights. It is available through APIs including OpenRouter, Upstage Console.
When was Solar Pro 4 released?
Upstage released Solar Pro 4 on 6 Aug 2026, according to models.dev.
Which providers offer Solar Pro 4?
We track Solar Pro 4 on 2 providers: OpenRouter, Upstage Console.
Change history
No changes detected since we started tracking this model. We re-check every source daily.