Zephyr Cloud Docs

    SSR Worker (beta)

    Zephyr’s SSR Worker is our runtime for serving server-rendered JavaScript applications at the edge. It runs your server entrypoint inside an isolate and serves the correct server/client assets for a deployed snapshot.

    Availability (important)

    Beta + Cloudflare-only
    • Beta: this feature is in active development and the API/behavior may change
    • Cloudflare-only: currently available only on Cloudflare
    • Default integration only: available only on Zephyr’s default (managed) Cloudflare integration
    • Not on BYOC: not available on Bring Your Own Cloud deployments (including custom/non-default integrations)

    How it relates to TanStack Start

    When you deploy a TanStack Start project using the Zephyr TanStack Start plugin, Zephyr uploads an SSR snapshot (server + client bundles) and configures the SSR Worker to execute the server entrypoint.

    See: TanStack Start.