Founded in 2023 by Alex Atallah, OpenRouter sits between an app and model providers (OpenAI, Anthropic, Google, open-weight labs, and others) and handles routing, fallback, and a single invoice. Stripe's August 19, 2026 investor letter called it the world's largest token routing engine, said token consumption was compounding at 9% per week year-to-date, and announced OpenRouter would join Stripe as its largest-ever acquisition, expected to close in the coming weeks.