Model Details
About
Upstage: Solar Pro 4 is a chat model built by Upstage. It accepts up to 524K tokens of context per request. Routed through external models — ~100 tokens per message (50% markup over upstream cost).
Use via API
curl https://api.free.ai/v1/chat/ \
-H "Authorization: Bearer YOUR_KEY" \
-d '{"model":"upstage/solar-pro4"}'
Compare
FAQ
Upstage: Solar Pro 4 is a chat model built by Upstage. It accepts up to 524K tokens of context per request. Routed through external models — ~100 tokens per message (50% markup over upstream cost).
Upstage: Solar Pro 4 works well for general conversation, writing assistance, brainstorming, code help, and analysis. Try the sample prompts above to see its style.
About 100 tokens per average message. Free accounts get a 30,000-token daily pool that covers self-hosted chat; premium models are pay-as-you-go, with token top-ups from $1.
It depends on the task. /chat/compare/ lets you send the same prompt to Upstage: Solar Pro 4 and any other model side-by-side - comparison is the fastest way to decide.
Yes. Outputs are yours - Free.ai does not claim rights to anything you generate.
524,288 tokens.
Replies stream token-by-token within ~1 second. Total response time depends on length and model size - small models stream faster, frontier models trade speed for depth.
Yes. Signed-in users see every chat in /account/?tab=history. You can also share a one-link copy of any conversation via the Share button.
Free.ai does not train models on your conversations. Self-hosted models stay on our GPUs. Premium models route to the upstream provider for inference.
Yes. POST to /v1/chat/ with model="upstage/solar-pro4" and a messages array. Streaming SSE is supported. Full reference: /api/.
Upstage: Solar Pro 4 is a premium model served by an external provider, so self-hosting is not available. Free.ai exposes it through token-based pricing.
Free accounts get a 30,000-token daily pool. When that runs out, token top-ups start at $1, pay-as-you-go - no subscription required.