vercel/next.js · error · Error

`cacheTag()` is only available with the `cacheComponents` co

Error message

`cacheTag()` is only available with the `cacheComponents` config.

What it means

Guard in cacheTag() that fires when the function is called while the cacheComponents experiment is disabled (__NEXT_USE_CACHE is falsy). It is a config gate, not a runtime failure: the input at fault is the use of cacheTag() in a project whose next.config has not enabled cacheComponents.

Source

Thrown at packages/next/src/server/use-cache/cache-tag.ts:6

import { workUnitAsyncStorage } from '../app-render/work-unit-async-storage.external'
import { validateTags } from '../lib/patch-fetch'

export function cacheTag(...tags: string[]): void {
  if (!process.env.__NEXT_USE_CACHE) {
    throw new Error(
      '`cacheTag()` is only available with the `cacheComponents` config.'
    )
  }

  const workUnitStore = workUnitAsyncStorage.getStore()

  switch (workUnitStore?.type) {
    case 'prerender':
    case 'prerender-client':
    case 'validation-client':
    case 'prerender-runtime':
    case 'prerender-legacy':
    case 'request':
    case 'unstable-cache':
    case 'generate-static-params':
    case undefined:
      throw new Error(
        '`cacheTag()` can only be called inside a "use cache" function.'

View on GitHub (pinned to 0eb3775416)

Solutions

1. Enable experimental.cacheComponents in next.config.js, or remove cacheTag() usage.

When it happens

Trigger: cacheTag() is called without the cacheComponents config enabled.

Common situations: Using cacheTag() in an app that has not enabled experimental cacheComponents.

AI-assisted analysis of vercel/next.js@0eb3775416 (2026-08-19). Data as JSON: /api/errors/0aacdecc1d16af41. Report an issue: GitHub.