The AI startups that customers will reliably shell out for are the ones that will ultimately survive and thrive.
Seems obvious enough, but it bears repeating in the AI industry’s financial funhouse-mirror landscape. ARR remains far from trustworthy, as the SaaS-era metric has been getting watered down: In some cases, companies fold in pilot revenue and one-time deals, bolstering the appearance of stability. Meanwhile, there’s a lot of anxiety around what it means for an AI tool to offer true ROI.
So I was intrigued by fintech Brex’s recent data outlining 2025’s 50 fastest-growing software vendors. The data is based on real spending, drawn from credit card and bill pay transactions from more than 35,000 anonymized Brex customers, that shows just who those customers are willing to pay for AI tools and services.
The data weighs recent months more heavily to select for companies that didn’t just soar and crash at the beginning of 2025. The data also filters out public companies and companies worth more than $30 billion, so it covers the category of companies I most worry about in a bubble burst—the unicorns valued, more or less, between $5 and $25 billion. Big enough to matter, but not too big to fail.
