How GitBook Runs 30,000 Sites with Sub-1-Second Content Updates

GitBook hosts 30,000 documentation sites through Vercel, handling 120 million page views per month. Companies like n8n, Nvidia, and Zoom receive fast and accurate documentation through this platform.

Previously, there was a problem where delays occurred between content edits and their reflection. GitBook introduced Next.js and Vercel's use cache directive, caching at the level of individual data-fetching functions rather than entire pages, which prevented duplicate API calls and increased efficiency.

To solve the cache invalidation problem in a multi-tenant environment, they built a tag-based invalidation approach. When a merge event occurs on Git or GitLab, only the relevant content tag is immediately revalidated, reflecting updates within 300ms without affecting other sites.

Notably, 41% of total traffic comes from AI crawlers and automated systems. Since AI scans vast numbers of pages in far more unpredictable ways than humans, maintaining a high cache hit rate has become a core challenge for managing infrastructure costs and performance.