feat: support passing Svelte(Kit) config via Vite plugin by dummdidumm · Pull Request #15944 · sveltejs/kit

dummdidumm · 2026-06-01T20:39:07Z

This allows you to pass the Svelte(Kit) config into the sveltekit Vite plugin. Example:

import { sveltekit } from '@sveltejs/kit/vite';
import { defineConfig } from 'vite';
import adapter from '@sveltejs/adapter-vercel';

export default defineConfig({
	plugins: [
		sveltekit({
			compilerOptions: {
				experimental: {
					async: true
				}
			},
			adapter: adapter(),
			experimental: {
				remoteFunctions: true,
				handleRenderingErrors: true
			}
		})
	],
});

Note how the kit namespace is at the same level as the other top level entries; this is the only difference to the current svelte.config.js layout.

If you set your options via the plugin, the svelte.config.js contents are ignored, so it's either-or, not a merge.

In SvelteKit 3 we will likely make it a requirement to pass the options via the Vite plugin instead - one less config file at the cluttered top level of your project.

Fixes #5485

Because you can tell Vite which config to use this also fixes #13748

Related: sveltejs/language-tools#3031

This allows you to pass the Svelte(Kit) config into the sveltekit Vite plugin. Example: ```js import { sveltekit } from '@sveltejs/kit/vite'; import { defineConfig } from 'vite'; import adapter from '@sveltejs/adapter-vercel'; export default defineConfig({ plugins: [ sveltekit({ compilerOptions: { experimental: { async: true } }, adapter: adapter(), experimental: { remoteFunctions: true, handleRenderingErrors: true } }) ], }); ``` Note how the `kit` namespace is at the same level as the other top level entries; this is the only difference to the current `svelte.config.js` layout. If you set your options via the plugin, the `svelte.config.js` contents are ignored, so it's either-or, not a merge. In SvelteKit 3 we will likely make it a requirement to pass the options via the Vite plugin instead - one less config file at the cluttered top level of your project. Fixes #5485 Because you can tell Vite which config to use this also fixes #13748

changeset-bot · 2026-06-01T20:39:14Z

🦋 Changeset detected

Latest commit: 9bcc42a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

svelte-docs-bot · 2026-06-01T20:41:46Z

Preview: https://svelte-dev-git-preview-kit-15944-svelte.vercel.app/

…tatement for `sveltekit`, which would cause a ReferenceError when users copy the code. This commit fixes the issue reported at documentation/docs/98-reference/50-configuration.md:44 **Bug Explanation:** The documentation at `documentation/docs/98-reference/50-configuration.md` shows an example vite.config.js file that demonstrates how to pass config to the `sveltekit` plugin. The example imports `adapter` from `@sveltejs/adapter-auto` and `defineConfig` from `vite`, but it uses `sveltekit({...})` in the plugins array without ever importing it. This would cause a `ReferenceError: sveltekit is not defined` if users copied this example directly into their projects. Every other vite.config.js file in the repository (at least 10+ files across playgrounds, packages/kit/test/, packages/adapter-static/test/, etc.) correctly imports sveltekit with: ```js import { sveltekit } from '@sveltejs/kit/vite'; ``` **Fix Explanation:** Added the missing import statement `import { sveltekit } from '@sveltejs/kit/vite';` to the documentation example, placing it between the adapter import and the defineConfig import to maintain alphabetical ordering by module path. This ensures users who copy the example code will have a working configuration. Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com> Co-authored-by: dummdidumm <sholthausen@web.de>

Rich-Harris · 2026-06-01T22:51:11Z

I don't understand the type errors... any ideas?

Rich-Harris · 2026-06-02T16:22:45Z

 /**
 * Returns the SvelteKit Vite plugins.
+ * Since version 2.62.0 you can also pass the Svelte config inline. The svelte.config.js will be ignored in this case.
+ * @param {KitConfig & Omit<SvelteConfig, 'onwarn'>} [inline_config]


why do we omit onwarn?

Because we have compilerOptions.warningFilter now, so it feels duplicative. We may want to remove onwarn for this reason at some point, so I'm omitting it here already

Rich-Harris · 2026-06-02T16:52:03Z

 export default config;
 ```

+Since version 2.62.0 you can also pass your configuration to the `sveltekit` plugin in your Vite config, along with the Svelte compiler options:


I actually think we should invert the docs to be Vite-first, but it will cause all sorts of ripple effects so I think it should happen later

yes, that was my thinking aswell 👍

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @sveltejs/kit@2.62.0 ### Minor Changes - feat: support passing Svelte(Kit) config via Vite plugin ([#15944](#15944)) ### Patch Changes - fix: preserve multiple `Set-Cookie` headers on 304 responses ([#15902](#15902)) - fix: preload for anchor elements that were just previously preloaded ([#15915](#15915)) - fix: catch load function streaming errors on the client ([#15929](#15929)) - fix: avoid generating the `_app/env.js` module if public dynamic environment variables are not used by the app ([#15940](#15940)) ## @sveltejs/package@2.5.8 ### Patch Changes - chore: bump `svelte2tsx` dependency to support TypeScript 6 ([#15896](#15896)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

BCsabaEngine · 2026-06-02T20:45:34Z

svelte-kit sync does not run without deleted svelte.config.js, because:

cli.js bails out early with a file-existence check before calling load_config(), which itself already supports reading from vite config. It's a one-line fix in the PR. The workaround is a stub svelte.config.js — its content is irrelevant since load_config() tries vite config first, but the file must exist to pass the check.

Rich-Harris · 2026-06-02T21:43:19Z

Whoops! Good catch, opened #15946

#15944 (comment) We missed a spot in #15944 — `svelte-kit sync` shouldn't check to see if a `svelte.config.js` exists, it should delegate to `load_config`. --- ### Please don't delete this checklist! Before submitting the PR, please make sure you do the following: - [x] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs - [x] This message body should clearly illustrate what problems it solves. - [ ] Ideally, include a test that fails without this PR but passes with it. ### Tests - [x] Run the tests with `pnpm test` and lint the project with `pnpm lint` and `pnpm check` ### Changesets - [x] If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running `pnpm changeset` and following the prompts. Changesets that add features should be `minor` and those that fix bugs should be `patch`. Please prefix changeset messages with `feat:`, `fix:`, or `chore:`. ### Edits - [x] Please ensure that 'Allow edits from maintainers' is checked. PRs without this option may be closed.

vercel Bot reviewed Jun 1, 2026

View reviewed changes

Comment thread documentation/docs/98-reference/50-configuration.md

dummdidumm and others added 2 commits June 1, 2026 22:54

lint

3a96c63

Rich-Harris reviewed Jun 1, 2026

View reviewed changes

Comment thread packages/kit/src/exports/vite/index.js

fix

3629427

Rich-Harris reviewed Jun 1, 2026

View reviewed changes

Comment thread packages/kit/src/exports/vite/index.js Outdated

Rich-Harris reviewed Jun 1, 2026

View reviewed changes

Comment thread packages/kit/src/core/config/index.js Outdated

Rich-Harris and others added 5 commits June 1, 2026 21:07

fix

202dfe8

shuffle around

17721d4

tweak

fbbe457

lint

f9c85d8

pass config to so we don't need to load it

22f9917

Rich-Harris force-pushed the vite-svelte-config branch from bd7541c to 22f9917 Compare June 2, 2026 16:10

tweak message

f204548

Rich-Harris reviewed Jun 2, 2026

View reviewed changes

Rich-Harris added 4 commits June 2, 2026 12:29

the hell?

38fc05c

tweak docs

ca3ea72

warn that svelte.config.js is ignored

30e9428

tweak docs

9bcc42a

Rich-Harris reviewed Jun 2, 2026

View reviewed changes

Rich-Harris approved these changes Jun 2, 2026

View reviewed changes

Rich-Harris merged commit 6bfb01f into main Jun 2, 2026
49 of 50 checks passed

Rich-Harris deleted the vite-svelte-config branch June 2, 2026 19:01

github-actions Bot mentioned this pull request Jun 2, 2026

Version Packages #15916

Merged

github-actions Bot mentioned this pull request Jun 2, 2026

Version Packages (next) #15311

Open

Rich-Harris mentioned this pull request Jun 2, 2026

fix: remove check for svelte.config.js before running sync #15946

Merged

6 tasks

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

feat: support passing Svelte(Kit) config via Vite plugin#15944

feat: support passing Svelte(Kit) config via Vite plugin#15944
Rich-Harris merged 14 commits into
mainfrom
vite-svelte-config

dummdidumm commented Jun 1, 2026 •

edited

Loading

Uh oh!

changeset-bot Bot commented Jun 1, 2026 •

edited

Loading

Uh oh!

svelte-docs-bot Bot commented Jun 1, 2026

Uh oh!

Uh oh!

Rich-Harris commented Jun 1, 2026

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Rich-Harris Jun 2, 2026

Uh oh!

dummdidumm Jun 2, 2026

Uh oh!

Rich-Harris Jun 2, 2026

Uh oh!

dummdidumm Jun 2, 2026

Uh oh!

Uh oh!

BCsabaEngine commented Jun 2, 2026

Uh oh!

Rich-Harris commented Jun 2, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Conversation

dummdidumm commented Jun 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

changeset-bot Bot commented Jun 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

🦋 Changeset detected

Uh oh!

svelte-docs-bot Bot commented Jun 1, 2026

Uh oh!

Uh oh!

Rich-Harris commented Jun 1, 2026

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Rich-Harris Jun 2, 2026

Choose a reason for hiding this comment

Uh oh!

dummdidumm Jun 2, 2026

Choose a reason for hiding this comment

Uh oh!

Rich-Harris Jun 2, 2026

Choose a reason for hiding this comment

Uh oh!

dummdidumm Jun 2, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

BCsabaEngine commented Jun 2, 2026

Uh oh!

Rich-Harris commented Jun 2, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

dummdidumm commented Jun 1, 2026 •

edited

Loading

changeset-bot Bot commented Jun 1, 2026 •

edited

Loading