Upstage AI: Solar Mini 4
upstage/solar-mini4
Try Solar Mini 4 for free in your browser, and add it to your app for free with Puter.js AI API.
Try it free Add to your app// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';
puter.ai.chat("Explain quantum computing in simple terms", {
model: "upstage/solar-mini4"
}).then(response => {
document.body.innerHTML = response.message.content;
});
<html>
<body>
<script src="https://js.puter.com/v2/"></script>
<script>
puter.ai.chat("Explain quantum computing in simple terms", {
model: "upstage/solar-mini4"
}).then(response => {
document.body.innerHTML = response.message.content;
});
</script>
</body>
</html>
Model Card
Solar Mini 4 is Upstage's compact, cost-efficient large language model, released September 23, 2026 as a smaller sibling to Solar Pro 4. It uses a 35-billion-parameter Mixture-of-Experts architecture with 3 billion active parameters, and shares its larger sibling's 524,288-token context window.
Upstage built it for agentic use cases where response speed and cost matter more than peak capability, with fluent Korean alongside strong English and Japanese support. Pricing is $0.05 per million input tokens and $0.20 per million output tokens.
Upstage has not published a benchmark table for Solar Mini 4, and no independent evaluation exists yet, so its accuracy relative to Solar Pro 4 or other models is unverified.
It suits developers building high-volume, latency-sensitive agents or long-context workflows in Korean, English, or Japanese who don't need Solar Pro 4's full capability.
Context Window 524K
tokens
Max Output 131K
tokens
Input Cost $0.05
per million tokens
Output Cost $0.2
per million tokens
Release Date Sep 23, 2026
Try Solar Mini 4 for free
Try Solar Mini 4 instantly in your browser.
This playground uses the Puter.js AI API — no API keys or setup required.
More AI Models From Upstage AI
Find other Upstage AI models →
Solar Pro 4
Solar Pro 4 is an agentic large language model from Upstage, built for multi-step work that spans documents, terminals, and tool calls, with a 524K token context window. Compared to Solar Pro 3, it shows large gains on agent-focused evaluations. Terminal-Bench v2.1 rose from 43.2 to 57, and AA-LCR long-document reasoning rose from 62.7 to 71. It scores 89.0 on GPQA Diamond and 81.9 on Arena-Hard v2 for Japanese. The model supports English, Korean, and Japanese, with adjustable reasoning effort for either deep analysis or faster responses. It is designed to flag when information can't be verified rather than fabricate an answer. Solar Pro 4 targets contract review, multi-document reconciliation, terminal-based automation, and document-heavy workflows like generating Excel, Word, and PowerPoint outputs.
ChatSolar Pro 3
Solar Pro 3 is a Mixture-of-Experts large language model from Upstage, featuring 102B total parameters with only 12B active per forward pass and a 128K token context window. The model is built for agentic workflows and complex reasoning, trained using Upstage's proprietary SnapPO reinforcement learning framework. It scores 72.3 on Tau2-all (the comprehensive agentic evaluation), roughly doubling its predecessor's 36.0. It also claims 100% schema compliance for structured output generation. Solar Pro 3 is particularly strong in Korean, with robust English and Japanese support — making it a standout choice for multilingual teams operating in East Asian markets. It targets enterprise use cases in domains like finance, healthcare, and legal, where reliable instruction following and structured outputs matter most.
Frequently Asked Questions
You can access Solar Mini 4 by Upstage AI through Puter.js AI API. Include the library in your web app or Node.js project and start making calls with just a few lines of JavaScript — no backend and no configuration required. You can also use it with Python or cURL via Puter's OpenAI-compatible API.
Solar Mini 4 is free to try with a Puter account. Every account includes a free AI allowance, and you can chat with it in the playground on this page. You can upgrade your account anytime for a larger allowance.
Solar Mini 4 is free to integrate using the Puter.js AI API. With the User-Pays Model, you can add AI to your app for $0, since users cover their own AI usage through their Puter account.
| Price per 1M tokens | |
|---|---|
| Input | $0.05 |
| Output | $0.2 |
Solar Mini 4 was created by Upstage AI and released on Sep 23, 2026.
Solar Mini 4 supports a context window of 524K tokens. For reference, that is roughly equivalent to 1,049 pages of text.
Solar Mini 4 can generate up to 131K tokens in a single response.
Yes — the Solar Mini 4 API works with any JavaScript framework, Node.js, or plain HTML through Puter.js. Just include the library and start building. See the documentation for more details.
Add Solar Mini 4 to your app for free
Developers can integrate Solar Mini 4 for free using the Puter.js AI API.
With the User-Pays Model, each user covers their own AI usage instead of the developer.