diff --git a/.changeset/vitest-5-shared-server-projects.md b/.changeset/vitest-5-shared-server-projects.md
new file mode 100644
index 00000000..1e9d9dbe
--- /dev/null
+++ b/.changeset/vitest-5-shared-server-projects.md
@@ -0,0 +1,5 @@
+---
+'vite-plugin-solid': patch
+---
+
+When the root config declares `test.projects` and leaves `test.sharedViteServer` unset, the plugin now sets it to `false` so every inline project resolves its own Vite config, as under Vitest 4. An explicit value is respected. Vitest 5 defaults the option to `true`, and a shared inline project takes its `test` options from the raw root block captured before any `config` hook runs, so it lost everything the plugin injects (the `jsdom` default, the `@testing-library/jest-dom` setup file, `server.deps`). Ports solidjs/solid-vite-plugin#370; refs #369.
diff --git a/.changeset/vitest-client-inline-runtime.md b/.changeset/vitest-client-inline-runtime.md
new file mode 100644
index 00000000..3cda3233
--- /dev/null
+++ b/.changeset/vitest-client-inline-runtime.md
@@ -0,0 +1,5 @@
+---
+'vite-plugin-solid': patch
+---
+
+In Vitest DOM tests (the jsdom default, no `ssr` option), the plugin now inlines `solid-js` and the packages that import it without a `solid` export condition, such as `@solidjs/testing-library`. Before, they stayed external, and the host runtime resolved their own imports. Node gets the `browser` condition from Vitest's worker `--conditions`, but Deno does not apply it in worker threads and resolves `deno`/`node`. Under Deno, `@solidjs/testing-library` loaded the server build of `solid-js/web` and `render` threw "Client-only API called on the server side" (solidjs/solid-vite-plugin#369). Inlining sends these imports through Vite's `browser` condition and loads one client-build instance. A `test.server.deps.inline` list is merged with the plugin's, and a `test.server.deps.external` entry for `solid-js` still opts out. With `ssr: true`, tests keep `solid-js` external as before.
diff --git a/.github/workflows/vitest.yml b/.github/workflows/vitest.yml
index fc062d92..ec6ac3cf 100644
--- a/.github/workflows/vitest.yml
+++ b/.github/workflows/vitest.yml
@@ -34,3 +34,7 @@ jobs:
       - name: Run tests
         working-directory: examples/vite-6
         run: pnpm run test
+
+      - name: Run jsdom tests
+        working-directory: examples/vite-6
+        run: pnpm run test:jsdom
diff --git a/examples/vite-6/package.json b/examples/vite-6/package.json
index a233ac35..fd5c45e2 100644
--- a/examples/vite-6/package.json
+++ b/examples/vite-6/package.json
@@ -7,13 +7,15 @@
     "build": "vite build",
     "preview": "vite preview",
     "test": "vitest --browser.headless --run",
-    "test-dev": "vitest"
+    "test-dev": "vitest",
+    "test:jsdom": "NODE_OPTIONS=--import=./tests/deno-conditions.mjs vitest --run --config vitest.jsdom.config.ts --pool=forks"
   },
   "devDependencies": {
     "@solidjs/testing-library": "^0.8.10",
     "@testing-library/jest-dom": "^6.6.3",
     "@testing-library/user-event": "^14.6.1",
     "@vitest/browser": "^3.0.7",
+    "jsdom": "^26.0.0",
     "playwright": "^1.50.1",
     "vite": "^6.2.0",
     "vite-plugin-solid": "workspace:*",
diff --git a/examples/vite-6/tests/deno-conditions.mjs b/examples/vite-6/tests/deno-conditions.mjs
new file mode 100644
index 00000000..a62dbf26
--- /dev/null
+++ b/examples/vite-6/tests/deno-conditions.mjs
@@ -0,0 +1,29 @@
+// Preloaded into the vitest workers (NODE_OPTIONS=--import) by `test:jsdom`.
+// It makes Node resolve bare imports the way Deno does in a worker thread.
+// Deno does not apply the `browser` condition that vitest passes to the
+// workers as `--conditions`, so an externalized package's own
+// `import "solid-js/web"` resolves `deno`/`node`, which is the server build
+// (solidjs/solid-vite-plugin#369).
+import module from 'node:module';
+
+const denoConditions = (context) => ({
+  ...context,
+  conditions: [...context.conditions.filter((c) => c !== 'browser'), 'deno'],
+});
+
+if (module.registerHooks) {
+  module.registerHooks({
+    resolve: (specifier, context, next) => next(specifier, denoConditions(context)),
+  });
+} else {
+  // Node < 22.15 has only the async loader API.
+  module.register(
+    'data:text/javascript,' +
+      encodeURIComponent(`
+        export async function resolve(specifier, context, next) {
+          const conditions = context.conditions.filter((c) => c !== 'browser');
+          return next(specifier, { ...context, conditions: [...conditions, 'deno'] });
+        }
+      `),
+  );
+}
diff --git a/examples/vite-6/tests/jsdom/testing-library.test.tsx b/examples/vite-6/tests/jsdom/testing-library.test.tsx
new file mode 100644
index 00000000..d90da1ea
--- /dev/null
+++ b/examples/vite-6/tests/jsdom/testing-library.test.tsx
@@ -0,0 +1,33 @@
+// jsdom regression test for solidjs/solid-vite-plugin#369, run by
+// `pnpm test:jsdom` with tests/deno-conditions.mjs preloaded.
+// `@solidjs/testing-library` has no `solid` export condition. Left external,
+// its own `import "solid-js/web"` is resolved by the host runtime, and under
+// Deno that is the server build, so `render` threw "Client-only API called
+// on the server side". The plugin inlines it with solid-js, so its imports
+// go through Vite's `browser` condition and share the test file's instance.
+import { render } from '@solidjs/testing-library';
+import { createSignal } from 'solid-js';
+import { isServer } from 'solid-js/web';
+import { expect, test } from 'vitest';
+
+function Counter() {
+  const [count, setCount] = createSignal(0);
+  return (
+    <button type="button" onClick={() => setCount(count() + 1)}>
+      count: {count()}
+    </button>
+  );
+}
+
+test('resolves the browser build in the test file', () => {
+  expect(isServer).toBe(false);
+});
+
+test('renders and updates through @solidjs/testing-library', () => {
+  const { getByRole, unmount } = render(() => <Counter />);
+  const button = getByRole('button');
+  expect(button.textContent).toBe('count: 0');
+  button.click();
+  expect(button.textContent).toBe('count: 1');
+  unmount();
+});
diff --git a/examples/vite-6/vitest.config.ts b/examples/vite-6/vitest.config.ts
index eb10c0e7..05ffcff4 100644
--- a/examples/vite-6/vitest.config.ts
+++ b/examples/vite-6/vitest.config.ts
@@ -1,4 +1,4 @@
-import { defineConfig } from 'vitest/config';
+import { configDefaults, defineConfig } from 'vitest/config';
 import solidPlugin from '../../src/index.js';
 
 export default defineConfig({
@@ -8,6 +8,8 @@ export default defineConfig({
   },
   test: {
     environment: 'node',
+    // tests/jsdom runs under vitest.jsdom.config.ts (`pnpm test:jsdom`).
+    exclude: [...configDefaults.exclude, 'tests/jsdom/**'],
     browser: {
       enabled: true,
       provider: 'playwright',
diff --git a/examples/vite-6/vitest.jsdom.config.ts b/examples/vite-6/vitest.jsdom.config.ts
new file mode 100644
index 00000000..37c61600
--- /dev/null
+++ b/examples/vite-6/vitest.jsdom.config.ts
@@ -0,0 +1,12 @@
+import { defineConfig } from 'vitest/config';
+import solidPlugin from '../../src/index.js';
+
+// jsdom suite (`pnpm test:jsdom`). The default vitest.config.ts runs the
+// browser-mode suite and excludes tests/jsdom.
+export default defineConfig({
+  plugins: [solidPlugin()],
+  test: {
+    environment: 'jsdom',
+    include: ['tests/jsdom/**/*.test.tsx'],
+  },
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index eed12c18..3c7bd36d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -148,6 +148,9 @@ importers:
       '@vitest/browser':
         specifier: ^3.0.7
         version: 3.0.7(@types/node@18.19.66)(playwright@1.50.1)(typescript@5.7.2)(vite@6.2.0(@types/node@18.19.66)(lightningcss@1.32.0))(vitest@3.0.7)
+      jsdom:
+        specifier: ^26.0.0
+        version: 26.0.0(supports-color@8.1.1)
       playwright:
         specifier: ^1.50.1
         version: 1.50.1
@@ -4303,7 +4306,6 @@ snapshots:
       '@csstools/css-parser-algorithms': 3.0.4(@csstools/css-tokenizer@3.0.3)
       '@csstools/css-tokenizer': 3.0.3
       lru-cache: 10.4.3
-    optional: true
 
   '@babel/code-frame@7.26.2':
     dependencies:
@@ -5156,14 +5158,12 @@ snapshots:
   '@colors/colors@1.5.0':
     optional: true
 
-  '@csstools/color-helpers@5.0.2':
-    optional: true
+  '@csstools/color-helpers@5.0.2': {}
 
   '@csstools/css-calc@2.1.2(@csstools/css-parser-algorithms@3.0.4(@csstools/css-tokenizer@3.0.3))(@csstools/css-tokenizer@3.0.3)':
     dependencies:
       '@csstools/css-parser-algorithms': 3.0.4(@csstools/css-tokenizer@3.0.3)
       '@csstools/css-tokenizer': 3.0.3
-    optional: true
 
   '@csstools/css-color-parser@3.0.8(@csstools/css-parser-algorithms@3.0.4(@csstools/css-tokenizer@3.0.3))(@csstools/css-tokenizer@3.0.3)':
     dependencies:
@@ -5171,15 +5171,12 @@ snapshots:
       '@csstools/css-calc': 2.1.2(@csstools/css-parser-algorithms@3.0.4(@csstools/css-tokenizer@3.0.3))(@csstools/css-tokenizer@3.0.3)
       '@csstools/css-parser-algorithms': 3.0.4(@csstools/css-tokenizer@3.0.3)
       '@csstools/css-tokenizer': 3.0.3
-    optional: true
 
   '@csstools/css-parser-algorithms@3.0.4(@csstools/css-tokenizer@3.0.3)':
     dependencies:
       '@csstools/css-tokenizer': 3.0.3
-    optional: true
 
-  '@csstools/css-tokenizer@3.0.3':
-    optional: true
+  '@csstools/css-tokenizer@3.0.3': {}
 
   '@cypress/request@3.0.7':
     dependencies:
@@ -6090,8 +6087,7 @@ snapshots:
       loupe: 3.1.3
       tinyrainbow: 2.0.0
 
-  agent-base@7.1.3:
-    optional: true
+  agent-base@7.1.3: {}
 
   aggregate-error@3.1.0:
     dependencies:
@@ -6360,7 +6356,6 @@ snapshots:
     dependencies:
       '@asamuzakjp/css-color': 2.8.3
       rrweb-cssom: 0.8.0
-    optional: true
 
   csstype@3.1.3: {}
 
@@ -6436,7 +6431,6 @@ snapshots:
     dependencies:
       whatwg-mimetype: 4.0.0
       whatwg-url: 14.1.1
-    optional: true
 
   dayjs@1.11.13: {}
 
@@ -6458,8 +6452,7 @@ snapshots:
     optionalDependencies:
       supports-color: 8.1.1
 
-  decimal.js@10.5.0:
-    optional: true
+  decimal.js@10.5.0: {}
 
   deep-eql@5.0.2: {}
 
@@ -6928,7 +6921,6 @@ snapshots:
   html-encoding-sniffer@4.0.0:
     dependencies:
       whatwg-encoding: 3.1.1
-    optional: true
 
   html-entities@2.3.3: {}
 
@@ -6938,7 +6930,6 @@ snapshots:
       debug: 4.4.0(supports-color@8.1.1)
     transitivePeerDependencies:
       - supports-color
-    optional: true
 
   http-signature@1.4.0:
     dependencies:
@@ -6952,7 +6943,6 @@ snapshots:
       debug: 4.4.0(supports-color@8.1.1)
     transitivePeerDependencies:
       - supports-color
-    optional: true
 
   human-id@1.0.2: {}
 
@@ -6965,7 +6955,6 @@ snapshots:
   iconv-lite@0.6.3:
     dependencies:
       safer-buffer: 2.1.2
-    optional: true
 
   ieee754@1.2.1: {}
 
@@ -7011,8 +7000,7 @@ snapshots:
 
   is-path-inside@3.0.3: {}
 
-  is-potential-custom-element-name@1.0.1:
-    optional: true
+  is-potential-custom-element-name@1.0.1: {}
 
   is-reference@1.2.1:
     dependencies:
@@ -7072,7 +7060,6 @@ snapshots:
       - bufferutil
       - supports-color
       - utf-8-validate
-    optional: true
 
   jsesc@3.0.2: {}
 
@@ -7191,8 +7178,7 @@ snapshots:
 
   loupe@3.1.3: {}
 
-  lru-cache@10.4.3:
-    optional: true
+  lru-cache@10.4.3: {}
 
   lru-cache@5.1.1:
     dependencies:
@@ -7288,8 +7274,7 @@ snapshots:
     dependencies:
       path-key: 3.1.1
 
-  nwsapi@2.2.16:
-    optional: true
+  nwsapi@2.2.16: {}
 
   object-inspect@1.13.3: {}
 
@@ -7623,8 +7608,7 @@ snapshots:
       '@rollup/rollup-win32-x64-msvc': 4.46.1
       fsevents: 2.3.3
 
-  rrweb-cssom@0.8.0:
-    optional: true
+  rrweb-cssom@0.8.0: {}
 
   run-parallel@1.2.0:
     dependencies:
@@ -7645,7 +7629,6 @@ snapshots:
   saxes@6.0.0:
     dependencies:
       xmlchars: 2.2.0
-    optional: true
 
   semver@6.3.1: {}
 
@@ -7789,8 +7772,7 @@ snapshots:
 
   supports-preserve-symlinks-flag@1.0.0: {}
 
-  symbol-tree@3.2.4:
-    optional: true
+  symbol-tree@3.2.4: {}
 
   term-size@2.2.1: {}
 
@@ -7850,7 +7832,6 @@ snapshots:
   tr46@5.0.0:
     dependencies:
       punycode: 2.3.1
-    optional: true
 
   tree-kill@1.2.2: {}
 
@@ -8059,24 +8040,19 @@ snapshots:
   w3c-xmlserializer@5.0.0:
     dependencies:
       xml-name-validator: 5.0.0
-    optional: true
 
-  webidl-conversions@7.0.0:
-    optional: true
+  webidl-conversions@7.0.0: {}
 
   whatwg-encoding@3.1.1:
     dependencies:
       iconv-lite: 0.6.3
-    optional: true
 
-  whatwg-mimetype@4.0.0:
-    optional: true
+  whatwg-mimetype@4.0.0: {}
 
   whatwg-url@14.1.1:
     dependencies:
       tr46: 5.0.0
       webidl-conversions: 7.0.0
-    optional: true
 
   which@2.0.2:
     dependencies:
@@ -8103,11 +8079,9 @@ snapshots:
 
   ws@8.18.1: {}
 
-  xml-name-validator@5.0.0:
-    optional: true
+  xml-name-validator@5.0.0: {}
 
-  xmlchars@2.2.0:
-    optional: true
+  xmlchars@2.2.0: {}
 
   y18n@5.0.8: {}
 
diff --git a/src/index.ts b/src/index.ts
index 82770246..fd2ce0c9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -214,6 +214,10 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin {
   let projectRoot = process.cwd();
   let isTestMode = false;
   let solidPkgsConfig: Awaited<ReturnType<typeof crawlFrameworkPkgs>>;
+  // Packages that import solid-js without a `solid` export condition, found
+  // by the crawl in test mode. They are inlined with solid-js (see
+  // `test.server.deps` below).
+  const testRuntimeConsumers = new Set<string>();
 
   return {
     name: 'solid',
@@ -235,6 +239,19 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin {
         isFrameworkPkgByJson(pkgJson) {
           return containsSolidField(pkgJson.exports || {});
         },
+        // Only records the runtime consumers for the jsdom test posture.
+        // Returning false keeps vitefu's output unchanged.
+        isSemiFrameworkPkgByJson(pkgJson) {
+          if (
+            isTestMode &&
+            !options.ssr &&
+            typeof pkgJson.name === 'string' &&
+            (pkgJson.dependencies?.['solid-js'] || pkgJson.peerDependencies?.['solid-js'])
+          ) {
+            testRuntimeConsumers.add(pkgJson.name);
+          }
+          return false;
+        },
       });
 
       // fix for bundling dev in production
@@ -255,12 +272,44 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin {
           test.environment = 'jsdom';
         }
 
+        // Vitest 5 defaults `test.sharedViteServer` to true: inline projects
+        // then reuse the root Vite server and take their `test` options from
+        // the raw root block captured before any `config` hook runs, so
+        // nothing injected here (jsdom, jest-dom, server.deps) reaches them.
+        // Vitest reads the option off the resolved root config, so this
+        // restores per-project resolution as under Vitest 4. Older Vitest
+        // versions ignore the option.
+        if (userTest.projects && userTest.sharedViteServer === undefined) {
+          test.sharedViteServer = false;
+        }
+
         if (
           !userTest.server?.deps?.external?.find((item: string | RegExp) =>
             /solid-js/.test(item.toString()),
           )
         ) {
-          test.server = { deps: { external: [/solid-js/] } };
+          if (options.ssr) {
+            test.server = { deps: { external: [/solid-js/] } };
+          } else if (userTest.server?.deps?.inline !== true) {
+            // An externalized package is imported natively, and its own
+            // imports are resolved by the host runtime, not by Vite. Node
+            // gets the `browser` condition from vitest's worker
+            // `--conditions`, but Deno (in a worker thread) resolves
+            // `deno`/`node` and lands on the server build: `render` from
+            // `@solidjs/testing-library` threw "Client-only API called on the
+            // server side" (#369). Inline solid-js and the packages that
+            // import it, so these imports go through Vite's `browser`
+            // condition and load one client-build instance. A consumer left
+            // external would load a second, native copy. Packages with a
+            // `solid` export condition are inlined already through vitefu.
+            // A user `inline` list is merged with this one; `inline: true`
+            // inlines everything already.
+            test.server = {
+              deps: {
+                inline: [/[\\/]node_modules[\\/]solid-js[\\/]/, ...testRuntimeConsumers],
+              },
+            };
+          }
         }
         if (!userTest.browser?.enabled) {
           // vitest browser mode already has bundled jest-dom assertions
@@ -301,7 +350,7 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin {
             : {}),
         },
         ...(!isVite6OrNewer ? { ssr: solidPkgsConfig.ssr } : {}),
-        ...(test.server ? { test } : {}),
+        ...(test.server || test.sharedViteServer === false ? { test } : {}),
       };
     },