Solar Pro 4

Name: Solar Pro 4
Author: Upstage

Free right now Frontier

ReasoningTool useLong context

Solar Pro 4 is a language model from Upstage. It is currently free at 1 provider with up to 524K tokens of context. The model supports step-by-step reasoning, supports tool calling.

Developer: Upstage
Context: 524K tokens
Type: Text
License: Proprietary

Where to use Solar Pro 4 for free

Each row is a separate free endpoint with its own limits.

Provider	Context	Limit	Card
Nous Portal `upstage/solar-pro4:free`	524K	The $0 Portal plan includes free models with standard rate limits. Model availability can change.	No	Open

Quick start

curl https://inference-api.nousresearch.com/v1/chat/completions \
  -H "Authorization: Bearer $NOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "upstage/solar-pro4:free",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

from openai import OpenAI

client = OpenAI(
    base_url="https://inference-api.nousresearch.com/v1",
    api_key="YOUR_NOUS_API_KEY",
)
reply = client.chat.completions.create(
    model="upstage/solar-pro4:free",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(reply.choices[0].message.content)

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://inference-api.nousresearch.com/v1",
  apiKey: process.env.NOUS_API_KEY,
});
const reply = await client.chat.completions.create({
  model: "upstage/solar-pro4:free",
  messages: [{ role: "user", content: "Hello!" }],
});
console.log(reply.choices[0].message.content);

Example for Nous Portal. Any OpenAI-compatible client works: Cursor, Cline, OpenCode, Open WebUI.