Solar - 2026 Pricing, Features, Reviews & Alternatives

Solar is a family of large language models (LLMs) developed for enterprise production environments, available in closed API-served variants (Solar Pro) and a commercially licensed open-weight variant (Solar Open 2). Deployment options span the Upstage Console (pay-as-you-go API), Amazon Bedrock Marketplace, Amazon SageMaker JumpStart, AWS Marketplace, on-premises infrastructure, and self-hosted deployment via Hugging Face. Target industries include finance, healthcare, legal, insurance, manufacturing, e-commerce, government, education, and nonprofit sectors, with multilingual coverage across English, Korean, and Japanese.

Solar models feature a hybrid inference architecture with selectable Chat Mode for fast responses and Reasoning Mode for structured, multi-step logical thinking using Chain-of-Thought (CoT). The Solar Pro 3 variant uses a Mixture-of-Experts (MoE) architecture (102B total parameters, 12B active per token), and Solar Open 2 scales to 250B total parameters with 15B active per token, delivering compute-efficient inference relative to parameter count. Solar Pro 4 supports a 512K context window with up to 128K output tokens and is trained on a proprietary data pipeline (OfficeVerse) synthesizing office tasks across 11 industry domains and 12 task types. Structured text understanding covers HTML, Markdown, tabular data, and JSON, with structured output support for enterprise system integration.

Agentic capabilities allow Solar models to autonomously plan and execute multi-step workflows, including tool calling (with MCP support), web search, code execution, file generation, and self-correction. Retrieval-Augmented Generation (RAG) compatibility and drop-in API versioning allow teams to upgrade model versions without configuration changes. A free-access program is available for eligible schools, hospitals, and nonprofits.