OpenRouter Raises $40 Million, Valued at $5 Billion, as AI Infrastructure Demand Surges

OpenRouter, an artificial intelligence infrastructure startup co-founded by former OpenSea co-founder Alex Atallah, has successfully completed a $40 million seed and Series A funding round. This significant investment was led by prominent venture capital firms Andreessen Horowitz and Menlo Ventures, with additional participation from Sequoia Capital and several well-known industry angel investors. The company is currently valued at $5 billion.

OpenRouter is positioned as an aggregation and routing platform for Large Language Models (LLMs). It brings together hundreds of models from various providers such as OpenAI, Anthropic, Meta, and others. The platform can automatically route user commands to the most suitable model based on cost, speed, accuracy, and privacy requirements. This unified approach eliminates the need for companies to rewrite integrations or switch contracts, streamlining the process of leveraging multiple AI models.

The $40 million investment will be instrumental in fueling OpenRouter’s expansion into enterprise markets and accelerating the development of its multi-provider routing and API platform. The company’s core product is a single, standardized API that allows businesses to route traffic across over 400 different large language models from providers such as OpenAI, Anthropic, Mistral, and Google. This financial backing underscores the growing importance of AI infrastructure in the tech industry and positions OpenRouter as a key player in the AI model marketplace.

OpenRouter’s platform has experienced rapid growth, with annualized usage scaling from $10 million in late 2024 to over $100 million by May 2025. This exponential increase in usage highlights the platform’s appeal to a wide range of customers, from early-stage startups to multinational corporations. The company’s success can be attributed to its focus on developer speed and enterprise guarantees, offering features such as zero-logging, automatic multi-cloud failover, standardized token accounting, and edge-deployed infrastructure with minimal overhead.

The platform’s architecture has attracted over one million developers since its launch in 2023. Enterprises gain access to real-time spend monitoring, unified billing, and the flexibility to blend their own inference capacity with OpenRouter’s burstable infrastructure. This has made OpenRouter an attractive choice for organizations concerned about data governance and unpredictable pricing, positioning the company as a trusted partner in the AI infrastructure landscape.

OpenRouter’s positioning has been further strengthened by integrations with various tools and platforms, including Microsoft VS Code, Zapier, Make.com, n8n, and Posthog. The company also played a key role in the stealth rollout of OpenAI’s GPT-4.1 model, providing customers with early access and generating valuable inference feedback. This collaboration has been instrumental in OpenRouter’s growth and has solidified its reputation as a reliable partner in the AI ecosystem.

The investment from Andreessen Horowitz and Menlo Ventures, along with the participation of Sequoia Capital and industry angels, reflects the confidence that leading venture capital firms have in OpenRouter’s vision and potential. The company’s ability to unify inference, normalize usage, and ensure uptime is setting a new standard for AI infrastructure. With deep partnerships with model providers and accelerating customer demand, OpenRouter is poised to become the backbone of AI integration across industries. As enterprises increasingly rely on multiple large language models, OpenRouter’s value proposition of speed, simplicity, and stability positions it as a critical player in the AI landscape.