AI model marketplace platform OpenRouter secures $40 million in funding, led by a16z and Menlo Ventures

ChainCatcher reports that AI model marketplace platform OpenRouter has completed $40 million in seed and Series A funding, with the company valued at approximately $500 million.

This round was led by Andreessen Horowitz and Menlo Ventures, with participation from Sequoia and several prominent industry investors. The funds will be used for product development, introducing new model types, and expanding enterprise support.

OpenRouter was founded in 2023 by OpenSea co-founder and CTO Alex Atallah and Louis Vichy. The platform provides a unified interface connecting over 400 large language models (LLMs), helping developers and enterprises streamline multi-model integration. Since its launch, the company has attracted over one million developers to use its API, with annual inference spending growing from $10 million in October 2024 to over $100 million by May 2025. Its clients range from startups to multinational corporations, supporting the routing of mission-critical traffic.