Sierra has raised a total of $635 million in funding across multiple rounds, reaching unicorn status in October 2024 after securing a $175 million Series A led by Greenoaks. Founded in 2023 and based in the United States, the company develops a conversational AI platform for customer service, enabling natural language interactions, real-time issue resolution, and advanced analytics. With a valuation of $10 billion as of September 2025, Sierra is backed by Iconiq Capital and Thrive Capital, positioning itself as a leader in AI-native customer engagement solutions.