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Upstage: Solar Pro 4

upstage/solar-pro4

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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 work, and coding.

When using BYOK with ZDR enforcement, the Console API key must belong to a ZDR-enabled Upstage organization. Contact Upstage to enable ZDR on your org.

Modalities
In / Out Price
70% off
$0.09 / $0.36per 1M
Context
524K
Released
Aug 10, 2026
Compare
ProvidersPricingPerformanceUptimeBenchmarksAppsActivityFAQExplore

Providers

Different companies host the same model. OpenRouter routes your request to one of them based on the routing mode you pick — Balanced (price + speed), Nitro (fastest), Floor (cheapest), or Exacto (highest tool-calling accuracy).

Pricing

The average price customers actually pay for this model, next to the prices providers post. Caching and discounts mean the price actually paid is often well below the listed one.

Performance

Throughput is how fast the model writes (tokens per second — higher is better). Latency is total round-trip time (lower is better). TTFT is time-to-first-token — how long before you see anything appear (lower is better).

Uptime

Uptime is the percentage of the past 3 days that at least one provider was responding to requests. Availability is the percentage of time that inference was successfully served. OpenRouter continuously monitors and uses the next-best provider when one returns an error.

Benchmarks

Scores on standardized evaluations and this model’s own outputs on shared benchmark prompts. Higher percentages are better — and each rank shows where this model lands among the models evaluated on that source.

Benchmark score summary for Upstage: Solar Pro 4 (Artificial Analysis and Design Arena)
SourceBenchmarkScore
Artificial AnalysisSolar Pro 4 Coding Index52.7
Artificial AnalysisSolar Pro 4 GPQA Diamond89.1%
Artificial AnalysisSolar Pro 4 HLE29.2%
Artificial AnalysisSolar Pro 4 AA-LCR74.0%
Artificial AnalysisSolar Pro 4 CritPt5.4%
Artificial AnalysisSolar Pro 4 SciCode44.6%
Artificial AnalysisSolar Pro 4 AA-Omniscience Accuracy18.9%
Artificial AnalysisSolar Pro 4 AA-Omniscience Non-Hallucination Rate75.6%
Design ArenaSolar Pro 4 Agents Arena Webapps Elo1115
Design ArenaSolar Pro 4 Models Arena 3D Elo1197
Design ArenaSolar Pro 4 Models Arena Code Categories Elo1191
Design ArenaSolar Pro 4 Models Arena Data Visualization Elo1188
Design ArenaSolar Pro 4 Models Arena Game Development Elo1184
Design ArenaSolar Pro 4 Models Arena UI Component Elo1160
Design ArenaSolar Pro 4 Models Arena Website Elo1184

Apps

Public apps that send the most traffic to this model. Good signal for what real production workloads look like — and a hint at which use cases this model is best suited for.

Activity

Token volume and request traffic to this model over time.

API

Drop-in code to call this model. OpenRouter's API is OpenAI-compatible — most SDKs work by just swapping the base URL. The only thing that changes between models is the model slug below.

Explore more models

AI Model RankingsRanking
70% off
$0.30$0.09$1.20$0.36$0.06$0.0180.88s30 tps
99.21%
70% off
$0.30$0.09$1.20$0.36$0.06$0.0182.17s44 tps
99.20%
Throughput
44tok/s

P50, best across providers

Latency
0.88s

P50, best provider

Uptime (3d)The model was reachable. Request routed to a provider.
100.00%
Availability (3d)The model returned inference from any provider. Errors and empty responses count against it.
98.32%

Availability over the last 3 days

Last 72 hours
Availability 98.32%
3 Days Ago2 Days AgoYesterdayNow

Availability over the last 24 hours

OpenRouter Availability
95.57%

When an error occurs in an upstream provider, we can recover by routing to another healthy provider, if your request filters allow it. You can access per-provider uptime data programmatically through the Endpoints API. Learn more about our load balancing and customization options.

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Frequently asked questions

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 work, and coding. When using BYOK with ZDR enforcement, the Console API key must belong to a ZDR-enabled Upstage organization. Contact Upstage to enable ZDR on your org.

Solar Pro 4 costs $0.09/M input tokens and $0.36/M output tokens, with separate rates for Cache Read at $0.018/M tokens.

Solar Pro 4 has a 524,288 token context window. It supports up to 131,072 completion tokens.

Yes. Solar Pro 4 accepts tools and tool_choice for function calling. It also supports structured outputs via a JSON schema in response_format.

Solar Decide, Solar Mini 4, and Solar Pro 3 are other text models from Upstage.

Solar Pro 4 was released on August 10, 2026.

More models from upstage

Solar Decide

Solar Decide is Upstage's structured decision model, served as a System One endpoint on Solar Mini 4. Send a state along with typed questions, and it returns a choice, a score, or a yes/no answer, each with a calibrated probability taken directly from the model rather than written out as text. Because it generates no prose, each decision takes a single forward pass and output tokens are free. With a 512K context window, an entire document can serve as the state. Solar Decide uses the same /v1/systemone schema as Jev, bringing Solar Mini 4's strong Korean understanding to routing, classification, and policy checks.

Decisions$0.05 / $0
Solar Mini 4

Solar Mini 4 is Upstage's compact, cost-efficient language model, a 35B-parameter mixture-of-experts with 3B active parameters and a 524K context window. It is built for agentic use cases where response speed and cost matter, with fluent Korean alongside strong English and Japanese, and support for long-context workloads.

When using BYOK with ZDR enforcement, the Console API key must belong to a ZDR-enabled Upstage organization. Contact Upstage to enable ZDR on your org.

Text524K context$0.05 / $0.20
Solar Pro 3

Solar Pro 3 is Upstage's powerful Mixture-of-Experts (MoE) language model. With 102B total parameters and 12B active parameters per forward pass, it delivers exceptional performance while maintaining computational efficiency. Optimized for Korean with English and Japanese support.

Text131K context$0.15 / $0.60