SSR Options

Unless noted, the options in this section are applied to both dev and build.

ssr.external

• Type: string[] | true
• Related: SSR Externals

Externalize the given dependencies and their transitive dependencies for SSR. By default, all dependencies are externalized except for linked dependencies (for HMR). If you prefer to externalize the linked dependency, you can pass its name to this option.

If true, all dependencies including linked dependencies are externalized.

Note that the explicitly listed dependencies (using string[] type) will always take priority if they're also listed in ssr.noExternal (using any type).

ssr.noExternal

• Type: string | RegExp | (string | RegExp)[] | true
• Related: SSR Externals

Prevent listed dependencies from being externalized for SSR, which they will get bundled in build. By default, only linked dependencies are not externalized (for HMR). If you prefer to externalize the linked dependency, you can pass its name to the ssr.external option.

If true, no dependencies are externalized. However, dependencies explicitly listed in ssr.external (using string[] type) can take priority and still be externalized. If ssr.target: 'node' is set, Node.js built-ins will also be externalized by default.

Note that if both ssr.noExternal: true and ssr.external: true are configured, ssr.noExternal takes priority and no dependencies are externalized.

ssr.target

• Type: 'node' | 'webworker'
• Default: node

Build target for the SSR server.

ssr.resolve.conditions

• Type: string[]
• Default: ['module', 'node', 'development|production'] (defaultServerConditions) (['module', 'browser', 'development|production'] (defaultClientConditions) for ssr.target === 'webworker')
• Related: Resolve Conditions

These conditions are used in the plugin pipeline, and only affect non-externalized dependencies during the SSR build. Use ssr.resolve.externalConditions to affect externalized imports.

ssr.resolve.externalConditions

• Type: string[]
• Default: ['node']

Conditions that are used during ssr import (including ssrLoadModule) of externalized direct dependencies (external dependencies imported by Vite).

TIP

When using this option, make sure to run Node with --conditions flag with the same values in both dev and build to get a consistent behavior.

For example, when setting ['node', 'custom'], you should run NODE_OPTIONS='--conditions custom' vite in dev and NODE_OPTIONS="--conditions custom" node ./dist/server.js after build.

ssr.resolve.mainFields

• Type: string[]
• Default: ['module', 'jsnext:main', 'jsnext']

List of fields in package.json to try when resolving a package's entry point. Note this takes lower precedence than conditional exports resolved from the exports field: if an entry point is successfully resolved from exports, the main field will be ignored. This setting only affect non-externalized dependencies.