Artificial intelligence startup Harvey on Monday announced it has reached $100 million in annual recurring revenue, or ARR, just three years after its launch. Harvey runs an AI-powered legal platform for lawyers at law firms and large corporations. Its technology can help with legal research, drafting and diligence projects, and the company is also building industry-specific use cases. Winston Weinberg, co-founder and CEO of Harvey, said the startup's ARR milestone has largely been driven by usage. Harvey has surpassed 500 customers, including CNBC's parent company, Comcast, and its weekly average users have quadrupled over the past year, the startup said. "Most of our accounts grow pretty massively," Weinberg told CNBC. "You'll sell to a Comcast or to a law firm, and they'll buy a couple hundred seats, and then they expand that usage pretty quickly." Weinberg is a former lawyer, and he co-founded Harvey with his friend and roommate Gabe Pereyra, a former research scientist at Google DeepMind and Meta . The pair launched the company in 2022 after experimenting with OpenAI's large language model GPT-3, which came out before its viral AI chatbot, ChatGPT.