outputHashSalt

outputHashSalt is an experimental option that incorporates a configurable salt string into every content-addressed output filename (chunks, assets). Changing this value forces all output hashes to change, which is useful for invalidating cached assets across deployments without modifying source files.

To configure the output hash salt, set experimental.outputHashSalt in next.config.js:

/** @type {import('next').NextConfig} */
const nextConfig = {
  experimental: {
    outputHashSalt: 'my-deployment-salt',
  },
}
 
module.exports = nextConfig

This works with both Webpack and Turbopack bundlers.

The NEXT_HASH_SALT environment variable can also be used for the same purpose. When both are set, the values are concatenated (experimental.outputHashSalt + NEXT_HASH_SALT) to form the effective salt. This lets you combine a per-project salt baked into the config with a per-deployment salt injected at build time via environment variable.

NEXT_HASH_SALT=my-deployment-salt next build

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