diff --git a/.claude/settings.local.json b/.claude/settings.local.json
index bbb73cf81..a34e92180 100644
--- a/.claude/settings.local.json
+++ b/.claude/settings.local.json
@@ -16,7 +16,11 @@
       "Bash(mkdir:*)",
       "Bash(TEST_ONLY=dev yarn vitest --config ./vitest.config.rolldown.ts --run --reporter=dot --color=false api-rolldown.test.ts)",
       "Bash(bun llink:*)",
-      "Bash(bun:*)"
+      "Bash(bun:*)",
+      "Bash(npm run dev:*)",
+      "Bash(npm run build:*)",
+      "Bash(npm run test:dev:*)",
+      "Bash(mv:*)"
     ],
     "deny": []
   }
diff --git a/packages/one/src/vite/__tests__/server-client-only.test.ts b/packages/one/src/vite/__tests__/server-client-only.test.ts
new file mode 100644
index 000000000..20fa3e422
--- /dev/null
+++ b/packages/one/src/vite/__tests__/server-client-only.test.ts
@@ -0,0 +1,79 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
+
+describe('server-only module', () => {
+  let originalEnv: string | undefined
+
+  beforeEach(() => {
+    originalEnv = process.env.VITE_ENVIRONMENT
+    vi.resetModules()
+  })
+
+  afterEach(() => {
+    if (originalEnv !== undefined) {
+      process.env.VITE_ENVIRONMENT = originalEnv
+    } else {
+      delete process.env.VITE_ENVIRONMENT
+    }
+  })
+
+  it('should throw an error when imported in client environment', async () => {
+    process.env.VITE_ENVIRONMENT = 'client'
+    
+    await expect(async () => {
+      await import('../server-only')
+    }).rejects.toThrow('This file should only be imported on the server! Current environment: client')
+  })
+
+  it('should not throw when imported in ssr environment', async () => {
+    process.env.VITE_ENVIRONMENT = 'ssr'
+    
+    await expect(import('../server-only')).resolves.not.toThrow()
+  })
+
+  it('should throw when VITE_ENVIRONMENT is not set', async () => {
+    delete process.env.VITE_ENVIRONMENT
+    
+    await expect(async () => {
+      await import('../server-only')
+    }).rejects.toThrow('This file should only be imported on the server! Current environment: undefined')
+  })
+})
+
+describe('client-only module', () => {
+  let originalEnv: string | undefined
+
+  beforeEach(() => {
+    originalEnv = process.env.VITE_ENVIRONMENT
+    vi.resetModules()
+  })
+
+  afterEach(() => {
+    if (originalEnv !== undefined) {
+      process.env.VITE_ENVIRONMENT = originalEnv
+    } else {
+      delete process.env.VITE_ENVIRONMENT
+    }
+  })
+
+  it('should throw an error when imported in ssr environment', async () => {
+    process.env.VITE_ENVIRONMENT = 'ssr'
+    
+    await expect(async () => {
+      await import('../client-only')
+    }).rejects.toThrow('This file should only be imported on the client! Current environment: ssr')
+  })
+
+  it('should not throw when imported in client environment', async () => {
+    process.env.VITE_ENVIRONMENT = 'client'
+    
+    await expect(import('../client-only')).resolves.not.toThrow()
+  })
+
+  it('should throw when VITE_ENVIRONMENT is not set', async () => {
+    delete process.env.VITE_ENVIRONMENT
+    
+    await expect(async () => {
+      await import('../client-only')
+    }).rejects.toThrow('This file should only be imported on the client! Current environment: undefined')
+  })
+})
\ No newline at end of file
diff --git a/packages/one/src/vite/client-only.ts b/packages/one/src/vite/client-only.ts
new file mode 100644
index 000000000..b706dd16a
--- /dev/null
+++ b/packages/one/src/vite/client-only.ts
@@ -0,0 +1,5 @@
+if (process.env.VITE_ENVIRONMENT !== 'client') {
+  throw new Error(`This file should only be imported on the client! Current environment: ${process.env.VITE_ENVIRONMENT}`)
+}
+
+export {}
\ No newline at end of file
diff --git a/packages/one/src/vite/one.ts b/packages/one/src/vite/one.ts
index 741948a40..2e5ad028f 100644
--- a/packages/one/src/vite/one.ts
+++ b/packages/one/src/vite/one.ts
@@ -19,6 +19,7 @@ import { generateFileSystemRouteTypesPlugin } from './plugins/generateFileSystem
 import { SSRCSSPlugin } from './plugins/SSRCSSPlugin'
 import { virtualEntryId } from './plugins/virtualEntryConstants'
 import { createVirtualEntry } from './plugins/virtualEntryPlugin'
+import { serverClientOnlyPlugin } from './plugins/serverClientOnlyPlugin'
 import type { One } from './types'
 import type {
   ExpoManifestRequestHandlerPluginPluginOptions,
@@ -143,6 +144,8 @@ export function one(options: One.PluginOptions = {}): PluginOption {
       __get: options,
     },
 
+    serverClientOnlyPlugin(),
+
     barrelOption === false
       ? null
       : (barrel({
diff --git a/packages/one/src/vite/plugins/__tests__/serverClientOnlyPlugin.test.ts b/packages/one/src/vite/plugins/__tests__/serverClientOnlyPlugin.test.ts
new file mode 100644
index 000000000..6d08e3c8e
--- /dev/null
+++ b/packages/one/src/vite/plugins/__tests__/serverClientOnlyPlugin.test.ts
@@ -0,0 +1,60 @@
+import { describe, it, expect } from 'vitest'
+import { resolve, dirname } from 'path'
+import { fileURLToPath } from 'url'
+import { serverClientOnlyPlugin } from '../serverClientOnlyPlugin'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = dirname(__filename)
+
+describe('serverClientOnlyPlugin', () => {
+  const plugin = serverClientOnlyPlugin()
+
+  it('should have correct plugin name', () => {
+    expect(plugin.name).toBe('one:server-client-only')
+  })
+
+  it('should enforce pre position', () => {
+    expect(plugin.enforce).toBe('pre')
+  })
+
+  describe('config hook', () => {
+    it('should provide aliases for server-only and client-only modules', () => {
+      const config = plugin.config?.()
+      
+      expect(config).toEqual({
+        resolve: {
+          alias: {
+            'server-only': resolve(__dirname, '../../server-only.js'),
+            'client-only': resolve(__dirname, '../../client-only.js'),
+          },
+        },
+      })
+    })
+  })
+
+  describe('resolveId hook', () => {
+    it('should resolve server-only module', () => {
+      const result = plugin.resolveId?.('server-only', undefined, {})
+      
+      expect(result).toEqual({
+        id: resolve(__dirname, '../../server-only.js'),
+        external: false,
+      })
+    })
+
+    it('should resolve client-only module', () => {
+      const result = plugin.resolveId?.('client-only', undefined, {})
+      
+      expect(result).toEqual({
+        id: resolve(__dirname, '../../client-only.js'),
+        external: false,
+      })
+    })
+
+    it('should return null for other modules', () => {
+      const result = plugin.resolveId?.('some-other-module', undefined, {})
+      
+      expect(result).toBeNull()
+    })
+  })
+})
\ No newline at end of file
diff --git a/packages/one/src/vite/plugins/serverClientOnlyPlugin.ts b/packages/one/src/vite/plugins/serverClientOnlyPlugin.ts
new file mode 100644
index 000000000..46655c779
--- /dev/null
+++ b/packages/one/src/vite/plugins/serverClientOnlyPlugin.ts
@@ -0,0 +1,34 @@
+import type { Plugin } from 'vite'
+import { resolve, dirname } from 'path'
+import { fileURLToPath } from 'url'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = dirname(__filename)
+
+export function serverClientOnlyPlugin(): Plugin {
+  return {
+    name: 'one:server-client-only',
+    enforce: 'pre',
+
+    config() {
+      return {
+        resolve: {
+          alias: {
+            'server-only': resolve(__dirname, '../server-only.js'),
+            'client-only': resolve(__dirname, '../client-only.js'),
+          },
+        },
+      }
+    },
+
+    resolveId(source) {
+      if (source === 'server-only') {
+        return { id: resolve(__dirname, '../server-only.js'), external: false }
+      }
+      if (source === 'client-only') {
+        return { id: resolve(__dirname, '../client-only.js'), external: false }
+      }
+      return null
+    },
+  }
+}
\ No newline at end of file
diff --git a/packages/one/src/vite/server-only.ts b/packages/one/src/vite/server-only.ts
new file mode 100644
index 000000000..9f74a8593
--- /dev/null
+++ b/packages/one/src/vite/server-only.ts
@@ -0,0 +1,5 @@
+if (process.env.VITE_ENVIRONMENT !== 'ssr') {
+  throw new Error(`This file should only be imported on the server! Current environment: ${process.env.VITE_ENVIRONMENT}`)
+}
+
+export {}
\ No newline at end of file
diff --git a/packages/one/types/vite/client-only.d.ts b/packages/one/types/vite/client-only.d.ts
new file mode 100644
index 000000000..a74e42e83
--- /dev/null
+++ b/packages/one/types/vite/client-only.d.ts
@@ -0,0 +1,2 @@
+export {};
+//# sourceMappingURL=client-only.d.ts.map
\ No newline at end of file
diff --git a/packages/one/types/vite/plugins/serverClientOnlyPlugin.d.ts b/packages/one/types/vite/plugins/serverClientOnlyPlugin.d.ts
new file mode 100644
index 000000000..b947d61d5
--- /dev/null
+++ b/packages/one/types/vite/plugins/serverClientOnlyPlugin.d.ts
@@ -0,0 +1,3 @@
+import type { Plugin } from 'vite';
+export declare function serverClientOnlyPlugin(): Plugin;
+//# sourceMappingURL=serverClientOnlyPlugin.d.ts.map
\ No newline at end of file
diff --git a/packages/one/types/vite/server-only.d.ts b/packages/one/types/vite/server-only.d.ts
new file mode 100644
index 000000000..b96d2bed6
--- /dev/null
+++ b/packages/one/types/vite/server-only.d.ts
@@ -0,0 +1,2 @@
+export {};
+//# sourceMappingURL=server-only.d.ts.map
\ No newline at end of file
diff --git a/packages/vxrn/src/exports/build.ts b/packages/vxrn/src/exports/build.ts
index 7f3aa6c46..53e4c32f4 100644
--- a/packages/vxrn/src/exports/build.ts
+++ b/packages/vxrn/src/exports/build.ts
@@ -243,7 +243,7 @@ export const build = async (optionsIn: VXRNOptions, buildArgs: BuildArgs = {}) =
 
     define: {
       'process.env.TAMAGUI_IS_SERVER': '"1"',
-      'process.env.VITE_ENVIRONMENT': '"server"',
+      'process.env.VITE_ENVIRONMENT': '"ssr"',
       ...processEnvDefines,
       ...webBuildConfig.define,
     },
diff --git a/tests/test/app/index.tsx b/tests/test/app/index.tsx
index a4336a3bd..ddba21294 100644
--- a/tests/test/app/index.tsx
+++ b/tests/test/app/index.tsx
@@ -53,6 +53,14 @@ export default () => {
         <Button>Go to hooks</Button>
       </Link>
 
+      <Link asChild href="/test-server-only">
+        <Button>Test Server Only</Button>
+      </Link>
+
+      <Link asChild href="/test-client-only">
+        <Button>Test Client Only</Button>
+      </Link>
+
       <ToggleThemeButton />
     </YStack>
   )
diff --git a/tests/test/app/test-client-only+spa.tsx b/tests/test/app/test-client-only+spa.tsx
new file mode 100644
index 000000000..0129b65c3
--- /dev/null
+++ b/tests/test/app/test-client-only+spa.tsx
@@ -0,0 +1,33 @@
+import { useState, useEffect } from 'react'
+import { Button, H2, Paragraph, YStack } from 'tamagui'
+
+export default function TestClientOnly() {
+  const [count, setCount] = useState(0)
+  const [browserInfo, setBrowserInfo] = useState<any>(null)
+
+  useEffect(() => {
+    // Only import client-only utilities on the client
+    if (typeof window !== 'undefined') {
+      import('../utils/client-utils').then(({ getBrowserInfo }) => {
+        setBrowserInfo(getBrowserInfo())
+      })
+    }
+  }, [])
+
+  return (
+    <YStack f={1} ai="center" jc="center" gap="$4" p="$4">
+      <H2>Client Only Test Page</H2>
+      <Paragraph>This page uses client-only utilities</Paragraph>
+      <Paragraph>Count: {count}</Paragraph>
+      <Button onPress={() => setCount(count + 1)}>Increment</Button>
+      <Paragraph fontSize="$2" color="$gray10">
+        Environment: {typeof window !== 'undefined' ? 'client' : 'server'}
+      </Paragraph>
+      {browserInfo && (
+        <Paragraph fontSize="$2" color="$gray10">
+          Browser: {browserInfo.language}
+        </Paragraph>
+      )}
+    </YStack>
+  )
+}
\ No newline at end of file
diff --git a/tests/test/app/test-server-only+ssr.tsx b/tests/test/app/test-server-only+ssr.tsx
new file mode 100644
index 000000000..8db0d8670
--- /dev/null
+++ b/tests/test/app/test-server-only+ssr.tsx
@@ -0,0 +1,26 @@
+import 'server-only'
+import { useLoader } from 'one'
+import { H2, Paragraph, YStack } from 'tamagui'
+import { getServerTime, getServerEnvironment } from '../utils/server-utils'
+
+export async function loader() {
+  // This loader should only run on the server
+  const serverInfo = getServerEnvironment()
+  return {
+    message: 'This data was loaded on the server',
+    timestamp: getServerTime(),
+    ...serverInfo
+  }
+}
+
+export default function TestServerOnly() {
+  const data = useLoader(loader)
+
+  return (
+    <YStack f={1} ai="center" jc="center" gap="$4" p="$4">
+      <H2>Server Only Test Page</H2>
+      <Paragraph>This page imports 'server-only' at the top</Paragraph>
+      <Paragraph>Loaded data: {JSON.stringify(data, null, 2)}</Paragraph>
+    </YStack>
+  )
+}
\ No newline at end of file
diff --git a/tests/test/routes.d.ts b/tests/test/routes.d.ts
index ef76fd05d..d102c734b 100644
--- a/tests/test/routes.d.ts
+++ b/tests/test/routes.d.ts
@@ -6,7 +6,7 @@ import type { OneRouter } from 'one'
 declare module 'one' {
   export namespace OneRouter {
     export interface __routes<T extends string = string> extends Record<string, unknown> {
-      StaticRoutes: `/` | `/(auth-guard)` | `/(auth-guard)/auth-guard` | `/(blog)` | `/(blog)/blog/my-first-post` | `/(marketing)/about` | `/(sub-page-group)` | `/(sub-page-group)/sub-page` | `/(sub-page-group)/sub-page/sub` | `/(sub-page-group)/sub-page/sub2` | `/_sitemap` | `/about` | `/auth-guard` | `/blog/my-first-post` | `/expo-video` | `/hooks` | `/hooks/cases/navigating-into-nested-navigator` | `/hooks/cases/navigating-into-nested-navigator/nested-1` | `/hooks/cases/navigating-into-nested-navigator/nested-1/nested-2` | `/hooks/cases/navigating-into-nested-navigator/nested-1/nested-2/page` | `/hooks/contents` | `/hooks/contents/page-1` | `/hooks/contents/page-2` | `/layouts` | `/layouts/nested-layout/with-slug-layout-folder/[layoutSlug]/` | `/loader` | `/loader/other` | `/middleware` | `/not-found/deep/test` | `/not-found/fallback/test` | `/not-found/test` | `/rn-features/platform-specific-extensions/test` | `/rn-features/platform-specific-extensions/test-route-1` | `/rn-features/platform-specific-extensions/test-route-2` | `/server-data` | `/sheet` | `/spa/spapage` | `/ssr` | `/ssr/` | `/ssr/basic` | `/sub-page` | `/sub-page/sub` | `/sub-page/sub2` | `/vite-features/import-meta-env` | `/web-extensions`
+      StaticRoutes: `/` | `/(auth-guard)` | `/(auth-guard)/auth-guard` | `/(blog)` | `/(blog)/blog/my-first-post` | `/(marketing)/about` | `/(sub-page-group)` | `/(sub-page-group)/sub-page` | `/(sub-page-group)/sub-page/sub` | `/(sub-page-group)/sub-page/sub2` | `/_sitemap` | `/about` | `/auth-guard` | `/blog/my-first-post` | `/expo-video` | `/hooks` | `/hooks/cases/navigating-into-nested-navigator` | `/hooks/cases/navigating-into-nested-navigator/nested-1` | `/hooks/cases/navigating-into-nested-navigator/nested-1/nested-2` | `/hooks/cases/navigating-into-nested-navigator/nested-1/nested-2/page` | `/hooks/contents` | `/hooks/contents/page-1` | `/hooks/contents/page-2` | `/layouts` | `/layouts/nested-layout/with-slug-layout-folder/[layoutSlug]/` | `/loader` | `/loader/other` | `/middleware` | `/not-found/deep/test` | `/not-found/fallback/test` | `/not-found/test` | `/rn-features/platform-specific-extensions/test` | `/rn-features/platform-specific-extensions/test-route-1` | `/rn-features/platform-specific-extensions/test-route-2` | `/server-data` | `/sheet` | `/spa/spapage` | `/ssr` | `/ssr/` | `/ssr/basic` | `/sub-page` | `/sub-page/sub` | `/sub-page/sub2` | `/test-client-only` | `/test-server-only` | `/vite-features/import-meta-env` | `/web-extensions`
       DynamicRoutes: `/dynamic-folder-routes/${OneRouter.SingleRoutePart<T>}/${OneRouter.SingleRoutePart<T>}` | `/hooks/contents/with-nested-slug/${OneRouter.SingleRoutePart<T>}` | `/hooks/contents/with-nested-slug/${OneRouter.SingleRoutePart<T>}/${OneRouter.SingleRoutePart<T>}` | `/hooks/contents/with-slug/${OneRouter.SingleRoutePart<T>}` | `/layouts/nested-layout/with-slug-layout-folder/${OneRouter.SingleRoutePart<T>}` | `/not-found/+not-found` | `/not-found/deep/+not-found` | `/routes/subpath/${string}` | `/segments-stable-ids/${string}` | `/spa/${OneRouter.SingleRoutePart<T>}` | `/ssr/${OneRouter.SingleRoutePart<T>}` | `/ssr/${string}`
       DynamicRouteTemplate: `/dynamic-folder-routes/[serverId]/[channelId]` | `/hooks/contents/with-nested-slug/[folderSlug]` | `/hooks/contents/with-nested-slug/[folderSlug]/[fileSlug]` | `/hooks/contents/with-slug/[slug]` | `/layouts/nested-layout/with-slug-layout-folder/[layoutSlug]` | `/not-found/+not-found` | `/not-found/deep/+not-found` | `/routes/subpath/[...subpath]` | `/segments-stable-ids/[...segments]` | `/spa/[spaparams]` | `/ssr/[...rest]` | `/ssr/[param]`
       IsTyped: true
diff --git a/tests/test/tests/server-client-only.test.ts b/tests/test/tests/server-client-only.test.ts
new file mode 100644
index 000000000..c53e78e65
--- /dev/null
+++ b/tests/test/tests/server-client-only.test.ts
@@ -0,0 +1,105 @@
+import { type Browser, type BrowserContext, chromium } from 'playwright'
+import { afterAll, beforeAll, describe, expect, it, test } from 'vitest'
+
+const serverUrl = process.env.ONE_SERVER_URL
+const isDebug = !!process.env.DEBUG
+
+let browser: Browser
+let context: BrowserContext
+
+beforeAll(async () => {
+  browser = await chromium.launch({ headless: !isDebug })
+  context = await browser.newContext()
+})
+
+afterAll(async () => {
+  await browser.close()
+})
+
+describe('Server-Client Only Module Tests', () => {
+  it('server-only modules should work on the server', async () => {
+    const page = await context.newPage()
+    // Navigate to the server-only test page
+    await page.goto(`${serverUrl}/test-server-only`)
+
+    // Wait for the page to load
+    await page.waitForSelector('text=Server Only Test Page')
+
+    // Check that the page loaded successfully
+    const heading = await page.textContent('h2')
+    expect(heading).toBe('Server Only Test Page')
+
+    // Check that server data was loaded
+    const loadedDataText = await page.textContent('p:has-text("Loaded data:")')
+    expect(loadedDataText).toContain('This data was loaded on the server')
+    
+    // Verify that the server environment info is present
+    const pageContent = await page.content()
+    expect(pageContent).toContain('nodeVersion')
+    expect(pageContent).toContain('platform')
+
+    await page.close()
+  })
+
+  it('client-only modules should work on the client', async () => {
+    const page = await context.newPage()
+    // Navigate to the client-only test page
+    await page.goto(`${serverUrl}/test-client-only`)
+
+    // Wait for the page to load
+    await page.waitForSelector('text=Client Only Test Page')
+
+    // Check that the page loaded successfully
+    const heading = await page.textContent('h2')
+    expect(heading).toBe('Client Only Test Page')
+
+    // Wait for client-side hydration
+    await page.waitForFunction(() => typeof window !== 'undefined')
+    
+    // The environment text shows 'client' after hydration
+    await page.waitForSelector('p:has-text("Environment: client")', { timeout: 5000 })
+
+    // Test client-side functionality
+    const button = await page.locator('button:has-text("Increment")')
+    
+    // Check initial count
+    let countText = await page.textContent('p:has-text("Count:")')
+    expect(countText).toBe('Count: 0')
+
+    // Click increment button
+    await button.click()
+    
+    // Check updated count
+    countText = await page.textContent('p:has-text("Count:")')
+    expect(countText).toBe('Count: 1')
+
+    // Wait for browser info to load (from dynamic import)
+    await page.waitForSelector('p:has-text("Browser:")', { timeout: 5000 })
+    const browserText = await page.textContent('p:has-text("Browser:")')
+    expect(browserText).toContain('Browser:')
+
+    await page.close()
+  })
+
+  it('server-only page should render server data', async () => {
+    const response = await fetch(`${serverUrl}/test-server-only`)
+    const html = await response.text()
+    
+    // Check that the page contains server-side rendered content
+    expect(html).toContain('Server Only Test Page')
+    expect(html).toContain('This page imports &#x27;server-only&#x27; at the top')
+    expect(html).toContain('This data was loaded on the server')
+  })
+
+  it('client-only page should render as SPA', async () => {
+    const response = await fetch(`${serverUrl}/test-client-only`)
+    const html = await response.text()
+    
+    // Check that this is a SPA page
+    expect(html).toContain('__vxrnIsSPA')
+    expect(html).toContain('"mode":"spa"')
+    // SPA pages don't render content on the server
+    expect(html).not.toContain('Client Only Test Page')
+    expect(html).not.toContain('userAgent')
+  })
+})
\ No newline at end of file
diff --git a/tests/test/utils/client-utils.ts b/tests/test/utils/client-utils.ts
new file mode 100644
index 000000000..e589ad90e
--- /dev/null
+++ b/tests/test/utils/client-utils.ts
@@ -0,0 +1,16 @@
+import 'client-only'
+
+export function getBrowserInfo() {
+  return {
+    userAgent: navigator.userAgent,
+    language: navigator.language,
+    onLine: navigator.onLine
+  }
+}
+
+export function getViewportSize() {
+  return {
+    width: window.innerWidth,
+    height: window.innerHeight
+  }
+}
\ No newline at end of file
diff --git a/tests/test/utils/server-utils.ts b/tests/test/utils/server-utils.ts
new file mode 100644
index 000000000..b18b0438f
--- /dev/null
+++ b/tests/test/utils/server-utils.ts
@@ -0,0 +1,13 @@
+import 'server-only'
+
+export function getServerTime() {
+  return new Date().toISOString()
+}
+
+export function getServerEnvironment() {
+  return {
+    nodeVersion: process.version,
+    platform: process.platform,
+    env: process.env.VITE_ENVIRONMENT
+  }
+}
\ No newline at end of file