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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.