Together AI raises $800M at $8.3B valuation on strong open-source adoption

What happened

Together AI, an AI infrastructure company founded in 2022, raised $800 million（約1300億円） in Series C funding at an $8.3 billion（約1.3兆円） valuation, led by Aramco Ventures with backing from Vista Equity Partners, General Catalyst, Emergence Capital, Nvidia, and others. The company last raised $305 million（約490億円） at $3.3 billion（約5300億円） valuation about 16 months ago.

Why it matters

Together AI claims annual bookings of over $1.15 billion（約1800億円） as businesses increasingly adopt cheaper open-source AI models through neocloud providers—companies offering AI-specific hardware and infrastructure—rather than paying premium prices for closed proprietary models. The trend suggests a structural shift in how enterprises are choosing to build AI systems, moving toward cost-effective alternatives.

What to watch

Together AI says open-source model usage has tripled across the industry in the past year, and the company counts thousands of paying customers including Cursor, Cognition, and Decagon. The broader neocloud sector has become a hot investment target, with competitors like Upscale AI and TensorWave raising comparable funding rounds in recent weeks.