Configuration

Rebask has two configuration sources. rebask() in vite.config.ts sets build-time options, and rebask.config.ts is read by the server at runtime.

rebask()

Pass options to rebask() in vite.config.ts:

import { rebask } from "@rebask/core/vite"

rebask({
  prerender: true,
  dedupeFetch: true,
  fullHtmlForBots: false,
})

prerender

rebask({ prerender: true })

Prerender static routes at build time. Enabled by default.

A route that was expected to be static but renders dynamically fails the build by default. Set failOnDynamic to false to log a warning instead:

rebask({ prerender: { failOnDynamic: false } })

Leave both enabled. Disabling prerender skips static shells, and disabling failOnDynamic lets routes go dynamic with only a build warning, losing PPR caching.

deploymentId

rebask({ deploymentId: process.env.DEPLOYMENT_ID })

Set a stable identifier for the current deployment, used for skew protection. When omitted, Rebask generates a fresh id on each production build, so a mismatch means the client is on a stale deployment.

configPath

rebask({ configPath: "./rebask.config.ts" })

Set the path to your rebask.config.ts. Relative paths resolve from the project root. When omitted, Rebask auto-detects rebask.config.{ts,mts,mjs,js} in the project root.

dedupeFetch

rebask({ dedupeFetch: true })

Deduplicate identical safe fetch requests within a single incoming request. Enabled by default. Only GET and HEAD requests are deduplicated, and passing signal to a fetch call opts that request out.

fullHtmlForBots

rebask({ fullHtmlForBots: false })

Wait for the full HTML instead of streaming Suspense fallbacks for crawler document requests.

Disabled by default because it makes crawler responses slower: the server waits for the whole page to resolve instead of streaming a shell right away.

markdownUrls

rebask({ markdownUrls: true })

Serve routes with a markdown.md or markdown.ts file at their .md URL in addition to Accept: text/markdown. Enabled by default. Set to false to disable .md URLs. See Agents to learn more.

clientTraceMetadata

rebask({ clientTraceMetadata: ["traceparent"] })

Header names to expose to the browser so client navigations, prefetch, and Server Function requests continue the server trace. Defaults to an empty list.

See Telemetry for SDK setup and emitted spans and metrics.

proxyTimeout

rebask({ proxyTimeout: 30_000 })

Set the timeout in milliseconds for external proxy rewrites. Defaults to 30 seconds. Set to null to disable.

shellPrerenderTimeout

rebask({ shellPrerenderTimeout: 30_000 })

Set how long in milliseconds a build prerender, upgrade, or background shell render waits for pending work before postponing the rest. Defaults to 30 seconds.

Dependencies that import React

Vite externalizes dependencies in the SSR environment by default. An externalized package that imports React resolves its own copy through Node instead of Vite's dedupe, which can produce an Invalid hook call error during SSR. Bundle that package instead:

// vite.config.ts
export default defineConfig({
  plugins: [rsc(), react(), rebask()],
  ssr: { noExternal: ["eve"] },
})

rebask.config.ts

Runtime configuration lives in rebask.config.ts. Every option is optional:

import type { RebaskConfig } from "@rebask/core"

export default {} satisfies RebaskConfig

cacheHandler

Set the CacheStorage implementation Rebask uses for server cache entries. Production defaults to a filesystem cache with an in-memory LRU. Development uses a no-op cache. Platform adapters may supply their own handler:

import type { RebaskConfig } from "@rebask/core"
import { CustomCacheHandler } from "./custom-handler"

export default {
  cacheHandler: new CustomCacheHandler(),
} satisfies RebaskConfig

If you want to change the default cache handler, extending BaseCacheStorage is recommended.

serverFunctions

export default {
  serverFunctions: {
    allowedOrigins: [],
    allowedForwardedHosts: [],
    bodySizeLimit: 1024 * 1024,
  },
} satisfies RebaskConfig

Configure security and runtime controls for Server Functions:

Each allowedOrigins and allowedForwardedHosts entry is a bare host without a scheme, such as example.com or localhost:3000, and supports *.example.com and **.example.com wildcards.

An empty allowedOrigins accepts only same-origin requests. An empty allowedForwardedHosts ignores X-Forwarded-Host.