How do I use Solar Pro 4 through YepAPI?

Sign up for a free API key, then send requests to the /v1/ai/chat endpoint.

UpstageText Generation/v1/ai/chat

Solar Pro 4

Access Solar Pro 4 through one API key. Upstage Cost-Efficient Long-Horizon LLM.

Solar Pro 4 is Upstage's cost-efficient large language model with a 524,288-token context window, built for long-horizon tasks and agentic workflows with strong capabilities in office productivity and document-intensive work. Solar Pro 4 suits document pipelines and back-office agents — contracts, reports, spreadsheets — that need a long context at a very low price.

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2,400+

Developers

1.2M+

API calls served

100+

Endpoints

$0.01

Per call

Yep, that's it.

Try it live

Send a message and see Solar Pro 4 respond in real time.

POST/v1/ai/chatupstage/solar-pro4

Message *

Max Tokens

Maximum tokens in the response.

Stream

Real-time tokens

Hit "Send Request" to see the response

Context Window

524K tokens

Max Output

131K tokens

Input Price

$0.13 / 1M tokens

Output Price

$0.53 / 1M tokens

Strengths

✓

Document and office work

Tuned for productivity and document-intensive tasks.

✓

524K context

Handles up to 524,288 input tokens and returns up to 131,072 output tokens per call.

✓

Very low cost

$0.13 per 1M input and $0.56 per 1M output tokens.

✓

Tools and structured output

Function calling and JSON schema outputs.

Quick start

Copy this snippet and start making calls with Solar Pro 4.

const res = await fetch('https://api.yepapi.com/v1/ai/chat', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "model": "upstage/solar-pro4",
    "messages": [
      {
        "role": "user",
        "content": "Explain API gateways in 2 sentences."
      }
    ],
    "maxTokens": 256
  }),
});
const { data } = await res.json();
console.log(data.message.content);

Why use Solar Pro 4 through YepAPI?

✓One API key for all models — no separate accounts

✓OpenAI SDK compatible — just change the base URL

✓No monthly minimums — pay per token

✓Switch models with one line of code

✓Full provider passthrough — citations, search results, and all extras included

✓Streaming and non-streaming support on every model

✓Works with Cursor, Claude, LangChain, and any LLM tool

✓Unified billing across all providers

Solar Pro 4 API — pricing, context window & access

Solar Pro 4 is Upstage's cost-efficient large language model with a 524,288-token context window, built for long-horizon tasks and agentic workflows with strong capabilities in office productivity and document-intensive work. It pairs a 524,288-token context window with up to 131,072 output tokens per response, at $0.13 per 1M input and $0.56 per 1M output tokens through YepAPI.

Through YepAPI you call Solar Pro 4 on an OpenAI-compatible endpoint with a single key — the same key that reaches GPT-6, Claude, Gemini, Grok and the SEO, SERP and scraping APIs. Input: text.

What is Solar Pro 4?

Solar Pro 4 is Upstage's cost-efficient large language model with a 524,288-token context window, built for long-horizon tasks and agentic workflows with strong capabilities in office productivity and document-intensive work. It returns up to 131,072 output tokens and is priced at $0.13 / $0.56 per 1M tokens. It accepts text as input, handles up to 524,288 tokens of context and returns up to 131,072 output tokens per call.

Build with Solar Pro 4 via YepAPI

YepAPI serves Solar Pro 4 on the OpenAI-compatible /v1/ai/chat endpoint. Point your base URL at YepAPI, add your key, and set the model string to solar-pro4 (or the full upstage/solar-pro4). Function calling, structured outputs and reasoning settings pass straight through, and switching to any other model on the platform is a one-string change per request.

Solar Pro 4 API pricing — $0.13 / 1M input, $0.56 / 1M output

Solar Pro 4 costs $0.13 per 1M input tokens and $0.56 per 1M output tokens through YepAPI, pay per token with no minimums. Failed calls are never charged, and every request is itemised in your dashboard API Logs so you can see exactly what a 131,072-token response cost.

Solar Pro 4 use cases

Solar Pro 4 suits document pipelines and back-office agents — contracts, reports, spreadsheets — that need a long context at a very low price.

Try Solar Pro 4 free

Every new YepAPI account includes $5 in free credit with no card required — enough to test Solar Pro 4 on your own prompts before committing to paid usage. Create an account, copy your key, and call solar-pro4 right away.