Treeline wants to rebuild corporate IT from the ground up, starting with the everyday headaches most workers barely notice until something breaks. The San Francisco–based startup has raised a $25 million Series A led by Andreessen Horowitz to build what it calls a “modern IT operating system, ” an AI and software-first alternative to the decades-old managed services firms still powering most corporate IT. The round comes as global IT spend is expected to climb above $6 trillion in 2026. “Basically every business in the world needs some form of IT management,” Peter Doyle, CEO and cofounder of Treeline, told Fortune. Most companies, he notes, can’t afford a full in-house department, so they outsource to a managed service provider—one of roughly 40,000 firms in the U.S. alone that handle everything from onboarding employees to fixing the Wi-Fi. The product those providers sell, as he sees it, is fundamentally “people and tools.” Teams of technicians stitch together dozens of point solutions to monitor environments, provision laptops, and respond to tickets, he says. Treeline’s bet is to flip that model. Instead of starting with people and layering in software, it starts with a unified software and AI layer, then brings technicians for judgment and oversight. The company says its AI agents now augment or directly resolve 98% of customer requests, and speed up employee onboarding from 20 minutes to 2 minutes. “What it takes is not being afraid to keep technicians and people in the loop,” Doyle says. “I’m not saying that we should replace technicians. We should empower them.”  Treeline uses its technicians‑in‑the‑loop model to automate lower level work like password resets so specialists can focus on “the really important tasks,” Doyle says.Doyle comes to the problem as an investor turned founder and operator. He previously spent about a decade in venture capital at Accel, backing IT infrastructure and security companies like Pagerduty, Heptio, and ServiceChannel. When we started Treeline, he thought building a better tool and selling it into that channel would be enough. “Within the first 10 days, we realized that wouldn’t work. We actually needed to fundamentally change how this industry operates,” he told Fortune. This story was originally featured on Fortune.com ...read more read less