Migration from v5
Environment API
As part of the new experimental Environment API, a big internal refactoring was needed. Vite 6 strives to avoid breaking changes to ensure most projects can quickly upgrade to the new major. We'll wait until a big portion of the ecosystem has moved to stabilize and start recommending the use of the new APIs. There may be some edge cases but these should only affect low level usage by frameworks and tools. We have worked with maintainers in the ecosystem to mitigate these differences before the release. Please open an issue if you spot a regression.
Some internal APIs have been removed due to changes in Vite's implementation. If you were relying on one of them, please create a feature request.
Vite Runtime API
The experimental Vite Runtime API evolved into the Module Runner API, released in Vite 6 as part of the new experimental Environment API. Given that the feature was experimental the removal of the previous API introduced in Vite 5.1 isn't a breaking change, but users will need to update their use to the Module Runner equivalent as part of migrating to Vite 6.
General Changes
Default value for resolve.conditions
This change does not affect users that did not configure resolve.conditions
/ ssr.resolve.conditions
/ ssr.resolve.externalConditions
.
In Vite 5, the default value for resolve.conditions
was []
and some conditions were added internally. The default value for ssr.resolve.conditions
was the value of resolve.conditions
.
From Vite 6, some of the conditions are no longer added internally and need to be included in the config values. The conditions that are no longer added internally for
resolve.conditions
are['module', 'browser', 'development|production']
ssr.resolve.conditions
are['module', 'node', 'development|production']
The default values for those options are updated to the corresponding values and ssr.resolve.conditions
no longer uses resolve.conditions
as the default value. Note that development|production
is a special variable that is replaced with production
or development
depending on the value of process.env.NODE_ENV
.
If you specified a custom value for resolve.conditions
or ssr.resolve.conditions
, you need to update it to include the new conditions. For example, if you previously specified ['custom']
for resolve.conditions
, you need to specify ['custom', 'module', 'browser', 'development|production']
instead.
JSON stringify
In Vite 5, when json.stringify: true
is set, json.namedExports
was disabled.
From Vite 6, even when json.stringify: true
is set, json.namedExports
is not disabled and the value is respected. If you wish to achieve the previous behavior, you can set json.namedExports: false
.
Vite 6 also introduces a new default value for json.stringify
which is 'auto'
, which will only stringify large JSON files. To disable this behavior, set json.stringify: false
.
Extended support of asset references in HTML elements
In Vite 5, only a few supported HTML elements were able to reference assets that will be processed and bundled by Vite, such as <link href>
, <img src>
, etc.
Vite 6 extends the support to even more HTML elements. The full list can be found at the HTML features docs.
To opt-out of HTML processing on certain elements, you can add the vite-ignore
attribute on the element.
postcss-load-config
postcss-load-config
has been updated to v6 from v4. tsx
or jiti
is now required to load TypeScript postcss config files instead of ts-node
. Also yaml
is now required to load YAML postcss config files.
Sass now uses modern API by default
In Vite 5, the legacy API was used by default for Sass. Vite 5.4 added support for the modern API.
From Vite 6, the modern API is used by default for Sass. If you wish to still use the legacy API, you can set css.preprocessorOptions.sass.api: 'legacy'
/ css.preprocessorOptions.scss.api: 'legacy'
. But note that the legacy API support will be removed in Vite 7.
To migrate to the modern API, see the Sass documentation.
Customize CSS output file name in library mode
In Vite 5, the CSS output file name in library mode was always style.css
and cannot be easily changed through the Vite config.
From Vite 6, the default file name now uses "name"
in package.json
similar to the JS output files. If build.lib.fileName
is set with a string, the value will also be used for the CSS output file name. To explicitly set a different CSS file name, you can use the new build.lib.cssFileName
to configure it.
To migrate, if you had relied on the style.css
file name, you should update references to it to the new name based on your package name. For example:
{
"name": "my-lib",
"exports": {
"./style.css": "./dist/style.css"
"./style.css": "./dist/my-lib.css"
}
}
If you prefer to stick with style.css
like in Vite 5, you can set build.lib.cssFileName: 'style'
instead.
Advanced
There are other breaking changes which only affect few users.
- [#15637] fix!: default
build.cssMinify
to'esbuild'
for SSRbuild.cssMinify
is now enabled by default even for SSR builds.
- [#18070] feat!: proxy bypass with WebSocket
server.proxy[path].bypass
is now called for WebSocket upgrade requests and in that case, theres
parameter will beundefined
.
- [#18209] refactor!: bump minimal terser version to 5.16.0
- Minimal supported terser version for
build.minify: 'terser'
was bumped to 5.16.0 from 5.4.0.
- Minimal supported terser version for
- [#18231] chore(deps): update dependency @rollup/plugin-commonjs to v28
commonjsOptions.strictRequires
is nowtrue
by default (was'auto'
before).- This may lead to larger bundle sizes but will result in more deterministic builds.
- If you are specifying a CommonJS file as an entry point, you may need additional steps. Read the commonjs plugin documentation for more details.
- [#18243] chore(deps)!: migrate
fast-glob
totinyglobby
- Range braces (
{01..03}
⇒['01', '02', '03']
) and incremental braces ({2..8..2}
⇒['2', '4', '6', '8']
) are no longer supported in globs.
- Range braces (
- [#18493] refactor!: remove fs.cachedChecks option
- This opt-in optimization was removed due to edge cases when writing a file in a cached folder and immediately importing it.
Migration from v4
Check the Migration from v4 Guide in the Vite v5 docs first to see the needed changes to port your app to Vite 5, and then proceed with the changes on this page.