Firecracker VMs enable sub-1s browser startup on EC2
Original: How we run Firecracker VMs inside EC2 and start browsers in less than 1s
Why This Matters
Demonstrates practical nested VM optimization for cost-sensitive cloud services; advances feasibility of per-user isolation in high-scale browser automation markets.
Browser Use rebuilt cloud infrastructure using Firecracker VMs inside EC2 instances, reducing browser session costs from $0.06 to $0.02 per hour while achieving sub-1-second startup times. The approach replaces previous unikernels system that required manual scaling.
Browser Use, an AI browser automation platform, redesigned its cloud infrastructure to run Firecracker lightweight virtual machines inside Amazon EC2 instances. Each browser session now runs in its own isolated Firecracker VM, enabling rapid provisioning and cost reduction. The company moved away from Unikraft unikernels after discovering the system could not auto-scale during traffic spikes—a load test in 2026 caused a 45-minute production outage when manual capacity adjustment was required. Firecracker VMs provide full isolation (each gets separate CPU, memory, disk, network), protecting against browser state leakage between sessions while keeping costs manageable. The architecture creates VMs inside VMs (nested virtualization on EC2), which normally adds performance overhead, but Browser Use optimized memory usage and Chromium startup procedures to achieve sub-1-second browser launch times. Session costs dropped from $0.06 to $0.02 per browser hour. The infrastructure handles thousands of concurrent VM creations and teardowns, enabling responsive scaling without human intervention. Browser Use's open-source library and managed cloud platform both use this optimized infrastructure, with 97% accuracy reported for automation tasks.