Upstage Solar API Pricing
The South Korean lab behind the Solar models, founded in October 2020 by Sung Kim — a former HKUST professor who led Naver's Clova team. Upstage pairs a compact, cost-efficient LLM line with a strong document-AI business, and in 2026 became Korea's first generative-AI unicorn.
Solar Pro 4
Upstage publishes a first-party retail rate card at upstage.ai/pricing/api.
Solar Pro 3
Upstage first-party rate card at upstage.ai/pricing/api: $0.15/M input, $0.015/M cached input, $0.60/M output, This model carries no reduction of its own: the 90% cut advertised on the same page co…
Solar Pro 2
Upstage first-party rate card at upstage.ai/pricing/api: $0.15/M input, $0.015/M cached input and $0.60/M output - the same card as Solar Pro 3.
| Model | Input /M | Output /M | Cached | Context | Max output | Vision | Tools | Tier |
|---|---|---|---|---|---|---|---|---|
| Solar Pro 4 FLAGSHIP | $0.30 | $1.20 | $0.06−80% | — | — | ✗ | ✓ | Frontier |
| Solar Pro 3 | $0.15 | $0.60 | $0.015−90% | — | — | ✗ | ✓ | Active |
| Solar Pro 2 LEGACY | $0.15 | $0.60 | $0.015−90% | — | — | ✗ | ✓ | Legacy |
Pricing across the lineup.
The Upstage story so far.
Company milestones and the Solar line. Sourced from Upstage's own newsroom, its pricing and docs pages, and Wikipedia.
console.upstage.ai — API keys, docs and playground. The endpoint is OpenAI-compatible at api.upstage.ai/v1, so migrating is a base-URL and model-name change rather than a rewrite.
Upstage's other half is document intelligence — parsing, OCR and information extraction, priced separately from the Solar chat models on its pricing page. It is the business the company is best known for in Korea.
OPEN WEIGHTSUpstage ships open-weight Solar models alongside the hosted API — the line that put it on the map when Solar 10.7B topped the Open LLM Leaderboard in 2023.
Upstage is a South Korean AI company founded in October 2020 by Sung Kim, a former professor at the Hong Kong University of Science and Technology who previously led Naver's Clova team. It is headquartered in Yongin, south of Seoul.
The company made its name twice over. First with document AI — parsing, OCR and extraction — which remains a large part of the business and is priced separately from the chat models. Then with Solar: in December 2023 Solar 10.7B topped the Hugging Face Open LLM Leaderboard, built using Upstage's own Depth-Up Scaling (DUS) technique, which grows a model by duplicating and re-stacking layers rather than training a larger one from scratch. The result was a compact model punching well above its parameter count — which is still the line's pitch.
Funding has escalated quickly: a $72M Series B in 2024 made it the most-funded South Korean AI software company at the time, and a ₩180 billion (~$122.3M) Series C-1 led by Sequoia Capital — with Hyundai Motor and Kia participating — pushed its valuation past ₩1 trillion and made it Korea's first generative-AI unicorn.
For buyers, the practical picture is this. The API is OpenAI-compatible, so trying it costs a base-URL change. Prices are low against Western frontier labs and roughly in the range of the cheaper Chinese labs, without the procurement questions a China-based vendor raises for some teams. The catch worth naming: Upstage does not publish a context window for the Solar models on any first-party page we could find, and published rate limits are modest at 100 requests/min — both matter more than the headline price if you are sizing a production workload.
Zhipu (Z.ai / GLM)
Similar price band with a far broader lineup, free tiers and open weights. But it is China-based and on the US Entity List, which is a procurement question Upstage does not raise.
CHEAPEST PEERDeepSeek
Cheaper still off-peak and MIT open weights, but it moved to peak/off-peak billing in August 2026, so its cost now depends on the hour. Upstage's rate is flat.
FRONTIER LEADERAnthropic
Leads coding and reasoning by a wide margin, with published context windows and mature enterprise terms. But an order of magnitude more expensive per token.
OPEN-WEIGHT PEERMistral
EU-native open weights with GDPR-first residency — the closest analogue to Upstage's compact-model pitch outside Asia, with a wider catalogue.
OPEN-WEIGHT GIANTAlibaba (Qwen)
The Qwen (Tongyi Qianwen) model family from Alibaba Cloud's Tongyi Lab. First released in 2023, Qwen is the most-downloaded open-weight model family in the world — most tiers ship under Apache 2.0 on Hugging Face and ModelScope, while the proprietary Max tier is served through Alibaba Cloud's Model Studio.
CHINA CONSUMER LEADERByteDance (Doubao)
The Doubao model family from ByteDance — parent of TikTok and Douyin. Served through the Volcano Ark (火山方舟) platform on ByteDance's Volcano Engine cloud, Doubao powers China's most-used consumer AI app and undercuts most frontier labs on price.
Frequently asked.
Practical questions about Solar pricing, the launch discount, and what Upstage does not publish.
Q · 01 Which Solar model should I start with? +
$0.03/$0.12. Just size your budget on its list price of $0.30/$1.20, because that is what applies from September 11, 2026. If you want a rate with no expiry attached, use Solar Pro 3 at $0.15/$0.60.Q · 02 Why does the flagship cost less than the mid tier right now? +
$0.03/$0.12 against Solar Pro 3's $0.15/$0.60; on September 11 the ordering flips and Pro 4 becomes twice the price of Pro 3.Q · 03 What context window do the Solar models have? +
Q · 04 How hard is it to migrate to Upstage? +
https://api.upstage.ai/v1 and pass a Solar model name. The real constraint is throughput — published rate limits are 100 requests/min and 50,000 tokens/min, which is modest next to the major labs and worth checking against your peak load before committing.Q · 05 Are reasoning tokens billed extra? +
usage.completion_tokens — the same bucket as the visible answer. The response exposes usage.completion_tokens_details.reasoning_tokens so you can see how much of a bill is thinking.