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Upstage: Solar Pro 4: AI model

Solar Pro 4 is a cost-efficient model for long, document-heavy agent work from Upstage with a 524K-token context window. Reachable from inside Iran through Hormouz.

Context window:
524,288 tokens
Input:
$0.09/1M tokens
Output:
$0.36/1M tokens
Discount:
−70%
Type:
text
  • Tools
  • Streaming
  • Long context
Good for:Popular for Programming · #11Ranks are based on global usage data

Thinking levels: max · xhigh · high · medium · low · minimal · none

Solar Pro 4 is Upstage's main language model, priced for volume and built around a 524K-token context. It is designed for long tasks and agent workflows, with particular strength in office productivity, document-heavy work and coding. Reasoning can be set anywhere from off to max.

It accepts text input and returns text, and supports tool calling, structured JSON output and streaming. Reasoning can be switched on when a problem needs more thought and left off when speed matters. Solar Pro 4 is commonly used for document-heavy analysis, office productivity agents, long-context summarisation and coding. Hormouz serves it behind an OpenAI-compatible API: point your base URL at Hormouz, drop in a Hormouz key, and existing OpenAI SDK code runs without changes.

Pricing is usage-based: $0.09 per million input tokens and $0.36 per million output tokens. There is no fixed monthly fee, and you pay only for the tokens you use. Hormouz provides stable access to the model from inside Iran, with no foreign credit card or circumvention tooling required.

Solar Pro 4 is Upstage's cost-efficient large language model, featuring a 524K context window. It is built for long-horizon tasks and agentic workflows, with strong capabilities in office productivity, document-intensive...

Quickstart

curl https://api.hormouz.net/v1/chat/completions \
  -H "Authorization: Bearer ng-YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "upstage/solar-pro4",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Specs

VendorUpstage
TypeText
Context window524,288 tokens
PricingPrevious price: $0.3 / $1.2 per MDiscounted price: $0.09 / $0.36 per M−70%
APIChat Completions
CapabilitiesStreaming · Tools

Benchmarks

52.7
Coding Index
Better than 59% of models we compared

Reasoning

GPQA Diamond
Graduate-level scientific reasoning
89.1%
HLE
Humanity's Last Exam
29.2%
AA-LCR
Long-context reasoning
74%
CritPt
Research-level physics reasoning
5.4%
AA Omniscience
Broad factual knowledge accuracy
18.9%
Non-Hallucination
Rate of avoiding fabricated answers
75.6%

Coding

SciCode
Python for scientific computing
44.6%

Agentic

GDPval
Economically valuable tasks
30.5%

Source: Artificial Analysis

Design Arena

How Design Arena works ↗
Web Apps
Top 83%
1,098Elo
Win rate: 30%
3D
Top 39%
1,189Elo
Win rate: 46.4%Avg time: 259s
Code
Top 42%
1,188Elo
Win rate: 39%Avg time: 288s
Data Viz
Top 49%
1,187Elo
Win rate: 41.3%Avg time: 235s
Game Dev
Top 46%
1,183Elo
Win rate: 39.9%Avg time: 382s
UI Component
Top 59%
1,156Elo
Win rate: 35.5%Avg time: 266s
Website
Top 52%
1,183Elo
Win rate: 37.5%Avg time: 290s

Metrics sourced from Design Arena

Code example

cURL
curl https://api.hormouz.net/v1/chat/completions \
  -H "Authorization: Bearer ng-YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "upstage/solar-pro4",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'
Python
from openai import OpenAI
client = OpenAI(api_key="ng-YOUR_API_KEY", base_url="https://api.hormouz.net/v1")
response = client.chat.completions.create(
    model="upstage/solar-pro4",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)
JavaScript
import OpenAI from "openai";
const client = new OpenAI({ apiKey: "ng-YOUR_API_KEY", baseURL: "https://api.hormouz.net/v1" });
const response = await client.chat.completions.create({
  model: "upstage/solar-pro4",
  messages: [{ role: "user", content: "Hello!" }],
});
console.log(response.choices[0].message.content);

Buy the Upstage: Solar Pro 4 API, paid in rial

  • Buy credit with an Iranian bank card; no foreign card or account needed.
  • One Hormouz key reaches Upstage: Solar Pro 4 and 600+ other models, and you pay only for what you use.
  • No VPN and no risk of a banned account; just change the base URL to api.hormouz.net/v1.
Create an account

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FAQ

How much does Solar Pro 4 cost?
Pricing is usage-based: $0.09 per million input tokens and $0.36 per million output tokens. There is no fixed monthly fee, and you pay only for the tokens you use.
How do I access Solar Pro 4 from inside Iran?
Create an account on Hormouz and generate an API key. Hormouz provides a stable path to the model from inside Iran, with no foreign credit card or circumvention tooling required.
Is Solar Pro 4 compatible with OpenAI code?
Yes. Hormouz exposes an OpenAI-compatible API. Point your base URL at Hormouz and swap in your Hormouz key. Your existing SDKs and code run without a rewrite.
What context window and capabilities does Solar Pro 4 have?
It has a 524K-token context window, accepts text input, and supports tool calling, structured JSON output and streaming. Reasoning can be switched on when a problem needs more thought and left off when speed matters.
What is Solar Pro 4 good for?
Typical uses are document-heavy analysis, office productivity agents, long-context summarisation and coding.

Updated 2026-10-13