How Vercel Cut Build Wait Times From 90 Seconds To 5
This title could be clearer and more informative.Try out Clickbait Shieldfor free (5 uses left this month).
Vercel's internal build platform, codenamed Hive, reduced build provisioning time from 90 seconds to 5 seconds (an 18x improvement) by adopting Firecracker microVMs instead of standard containers. The core problem was hostile multi-tenancy: customer build scripts run on shared hardware and could be malicious, making container-level isolation insufficient. Firecracker provides VM-level kernel isolation while booting in ~125ms. Three stacked optimizations drove the speedup: local caching of build container images (saving ~45s), a warm pool of pre-booted cells that eliminates cold-start latency for most builds, and Firecracker's inherently fast boot times that make warm pools practical at scale. Each cell is destroyed after every build to prevent state leakage between customers. The architecture also enabled product features like enhanced build machines and Secure Compute for enterprise customers. The tradeoff is significant engineering investment and ongoing compute costs for idle warm-pool cells.
