OpenRouter, the unified interface for large-language-model (LLM) inference, announced that it has closed a combined Seed and Series A financing of $40 million led by Andreessen Horowitz and Menlo Ventures, with participation from Sequoia and prominent industry angels.

The investment will accelerate product development, bring new types of models to the platform, and expand enterprise support as OpenRouter becomes the default backbone for organizations that rely on multiple AI models.