Solar Pro 4 API

Upstage's Solar Pro 4: large-context (512K) chat model for agentic workflows, office productivity, document-intensive work, and coding.

Modalities
Image, TextText
In / Out price
$0.0952/$0.3809per 1M
Context window
512K tokens
Released
Aug 10, 2026

Solar Pro 4 overview

The pelican test: one prompt, every text model, unedited SVG output from Nov 3, 2026.

SVG of a pelican riding a bicycle, written by Solar Pro 4 through AI/ML API

Solar Pro 4 by Upstage

Solar Pro 4 is Upstage's large language model with a 512K-token context window, built for agentic workflows, office productivity, document-intensive work, and coding.

Solar Pro 4 specs

Model ID
upstage/solar-pro4
Developer
Upstage
Context window
524,288 tokens
Max output
131,072 tokens
Input
Image, Text
Output
Text
API
OpenAI-compatible, base URL https://api.aimlapi.com/v1

Coding and code review
Generate, debug, and review code across languages, reading whole files or repos in a single prompt.

Agentic and multi-step workflows
Reliable tool-calling and instruction-following suit agent loops that plan, call tools, and iterate.

Office productivity and document-intensive work
Draft, summarize, and reason over large documents and reports without aggressive chunking, thanks to the 512K-token context window.

Use cases

Solar Pro 4 is documented as suited to document understanding and information extraction, including workflows that read source material and ground answers in evidence. It is also documented for long-context contract and filing review, where many pages or multiple documents are processed in a single session. Another stated use case is terminal-based automation and other multi-step agentic workflows that chain tool calls over many steps. It is also described as fitting office productivity and document-intensive work such as generating structured deliverables from business documents.

Capabilities

  • Function calling
  • Reasoning
  • Streaming
  • Structured outputs
  • Vision
  • Web search

Solar Pro 4 benchmarks by Artificial Analysis

See how Solar Pro 4 compares in generation speed and latency. Data retrieved Nov 4, 2026.

Speed

Output tokens / second

Benchmark results

Compare 18 models available on AI/ML API across 5 independent benchmarks.

Humanity's Last Exam

Expert-written questions across academic subjects.

Solar Pro 4 API pricing

Solar Pro 4 pricing in US dollars
UsagePriceUnit
Input$0.09521M tokens
Output$0.38091M tokens
Cached input$0.0191M tokens

Prices from the AI/ML API price list, checked on Nov 4, 2026.

Solar Pro 4 vs other models: token prices

AI/ML API input and output rates for 5 models, per million tokens.

AI/ML API model prices in USD per million tokens
ModelInputOutput
Solar Pro 4$0.0952$0.3809
Ministral 3 14B 2512$0.3703$0.3703
Dola-Seed 2.0 Mini$0.1$0.4
GPT-5 Nano$0.05$0.4
Solar Mini 4$0.1058$0.4232

How to use the Solar Pro 4 API

View docs

Build with your agent

Give your agent the model details, code and documentation.

1Get your API key

Create API key
export AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"

2Make your first request

curl 'https://api.aimlapi.com/v1/chat/completions' \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "upstage/solar-pro4",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'

Related articles

All posts

Solar Pro 4 FAQ

What is the context window of Solar Pro 4?

Solar Pro 4 has a 524,288 tokens context window and can return up to 131,072 tokens.

What inputs and outputs does Solar Pro 4 support?

Solar Pro 4 takes image, text as input and returns text.

What is the model ID for Solar Pro 4?

Use upstage/solar-pro4 as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

When was Solar Pro 4 released?

Solar Pro 4 became available on August 10, 2026.

How much does Solar Pro 4 cost?

Solar Pro 4 costs $0.0952 input and $0.3809 output per 1M tokens on AI/ML API, billed as you go with no subscription.

Does Solar Pro 4 support streaming?

Yes, Solar Pro 4 can stream responses as they are generated.

Can Solar Pro 4 read images?

Yes, Solar Pro 4 accepts image input alongside text.

Who created Solar Pro 4?

Solar Pro 4 was built by Upstage.

What tasks is Solar Pro 4 designed for?

Solar Pro 4 is suited for agentic workflows, office productivity, document-intensive work, and coding.

Does Solar Pro 4 support tool use and function calling?

Yes, Solar Pro 4 supports function calling, parallel tool calls, and structured outputs.

Start building with Solar Pro 4

Solar Pro 4 API

upstage/solar-pro4

Build with your agent

Give your agent the model details, code and documentation.

1Get your API key

Create API key
export AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"

2Make your first request

curl 'https://api.aimlapi.com/v1/chat/completions' \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "upstage/solar-pro4",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'