From latency to instant: Modernizing GitHub Issues navigation performance

GitHub Issues redesigns navigation architecture to prioritize perceived latency using client-side caching and service workers, shifting work from server to client.

• •IndexedDB-backed persistent cache implements Stale-While-Revalidate pattern for React soft navigations, enabling 22% of navigations to reach instant (<200ms) performance
• •HPC (Highest Priority Content) metric guides optimization toward rendering primary content within 200ms instead of optimizing backend latency alone
• •Three navigation types analyzed—hard navigation (full browser load), Turbo navigation (Rails transitions), and soft navigation (React client-side)—with strategy focused on reducing hard-navigation penalty
• •Service worker enables cached data persistence across hard navigations, improving experience on cold starts and browser refreshes