As businesses new and old rush to take advantage of AI, many AI startups say their revenues aren’t just growing, they’re accelerating rapidly and reaching their next milestone in a shorter time frame.
The list of startups below reports such a flywheel growth pattern. One thing to note is that even though they use the term “ARR”, the underlying metrics these companies use are different. Some may refer to annualized recurring revenue (ARR), or contractual revenue that you pay for but have not yet billed. Some refer to annualized run-rate returns, and others project annual returns by calculating trailing 12-month returns at the most recent month’s rate. Some refer to “committed ARR,” or signed agreements from customers who have not yet been onboarded. In the case of Gusto, we reported actual revenue for the past 12 months.
Nevertheless, each of these startups, listed in reverse chronological order to when ARR growth was published, reports accelerating revenue growth, but does not define it. To be sure, there are many more fast-growing AI startups than those listed here, but we’ve limited this list to companies that are reaching revenue milestones faster than ever before.
Melkor: On Monday, Melkor co-founder and CEO Brendan Foudy announced that the company’s annual revenue exceeded $2 billion as of June. This comes just four months after reaching the $1 billion milestone. The less than three-year-old company, which employs subject matter experts to train and improve AI models, announced in September that it reached $500 million in utilization.
Anthropic: In recent months, this model maker’s revenue has been growing at historic rates, captivating the entire AI sector. In late May, Anthropic announced that its revenue run rate had topped $47 billion, a metric that came less than two months after the company reported that the same metric had topped $30 billion. The company announced that it had reached a revenue run rate of $9 billion in the second half of 2025, up from the $4 billion reported in July 2025.
Sierra: After hitting $100 million in ARR for the first time in seven quarters, Sierra, which builds enterprise customer service AI agents, took just two quarters to add another $100 million, co-founder and CEO Brett Taylor announced in late May.
Green: In May, Green announced that ARR exceeded $300 million. While it took the seven-year-old enterprise AI startup nine months to double ARR from $100 million to $200 million, the company says it took just six months to grow that metric from $200 million to $300 million.
Gusto: The 14-year-old HR technology startup announced in May that its revenue accelerated in each of the past five quarters. The company was valued at $9.3 billion at the beginning of 2022, but has since reported 12-month sales of more than $1 billion. Gusto’s revenue surge shows that AI-native companies are not the only companies seeing significant revenue growth from technology integration.
Clio: This 18-year-old law practice management software provider has seen its revenue soar since incorporating AI into its products in 2023. The company announced ARR of over $200 million in mid-2024, doubling that number by the end of last year, and recently hitting $500 million in ARR.
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