Quick take:

  • The funding also attracted participation from Sequoia Capital and several angel investors.

  • The AI product development and ranking platform claims more than one million developers have used OpenRouter’s API since its launch two years ago.

  • Annual run-rate inference spend on OpenRouter increased from $10M in October last year to $100M in May, according to a press release seen by NFTgators.

OpenRouter, the unified interface for LLMs founded by a former OpenSea co-founder, Alex Atallah and Louis Vichy, has raised $40 million in a Series A round co-led by Andreessen Horowitz (A16z) and Menlo Ventures. The fundraising also attracted participation from Sequoia Capital and notable angel investors.

The company plans to use the fresh capital to accelerate product development, bring new types of models to the platform, and expand enterprise support. 

OpenRouter offers an AI development platform that allows developers and enterprises to tap into over 400 Large Language Models (LLMs) from OpenAI, Anthropic, Google, Mistral and more—without rewriting code or renegotiating contracts.

The company’s API platform has been used by more than 1 million developers, with the annual run-rate inference spend growing from $10 million last October to $100 million in May, according to a press release seen by NFTgators.

The platform is already integrated with the leading development platforms, including Microsoft VSCode, Zapier, Cloudflare, Make.com, n8n, and Posthog, among others. OpenRouter recently collaborated with OpenAI on the stealth launch of the GPT 4.1 model. 

Commenting on the announcement, Alex Atallah, co-founder and CEO of OpenRouter, said in a statement: “Inference is the fastest-growing cost for forward-looking companies, and it’s often coming from 4 or more different models. The sophisticated companies have run into these problems already and built some sort of in-house gateway. But they’re realising that making LLM’s “just work” isn’t an easy problem. They’re ripping out home-grown solutions and bringing in OpenRouter so they can focus on their domain-specific problems, and not on LLM integration.”

Anjney Midha, General Partner at Andreessen Horowitz, commented: “AI stacks are fragmenting. OpenRouter is unifying them with one API, one contract, and industry-leading uptime—exactly the kind of infrastructure play that defines new categories.”

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The post A16z and Menlo Ventures Co-Lead $40M Series A for AI Startup OpenRouter appeared first on NFTgators .