diff --git a/e2e/react-start/css-modules/tests/css.spec.ts b/e2e/react-start/css-modules/tests/css.spec.ts
index a823b5a693f..02dd96d30c8 100644
--- a/e2e/react-start/css-modules/tests/css.spec.ts
+++ b/e2e/react-start/css-modules/tests/css.spec.ts
@@ -12,28 +12,6 @@ const whitelistErrors = [
 test.describe('CSS styles in SSR (dev mode)', () => {
   test.use({ whitelistErrors })
 
-  // Warmup: trigger Vite's dependency optimization before running tests
-  // This prevents "optimized dependencies changed. reloading" during actual tests
-  // We use a real browser context since dep optimization happens on JS load, not HTTP requests
-  test.beforeAll(async ({ browser, baseURL }) => {
-    const context = await browser.newContext()
-    const page = await context.newPage()
-    try {
-      // Load both pages to trigger dependency optimization
-      await page.goto(baseURL!)
-      await page.waitForTimeout(2000) // Wait for deps to optimize
-      await page.goto(`${baseURL}/modules`)
-      await page.waitForTimeout(2000)
-      // Load again after optimization completes
-      await page.goto(baseURL!)
-      await page.waitForTimeout(1000)
-    } catch {
-      // Ignore errors during warmup
-    } finally {
-      await context.close()
-    }
-  })
-
   // Helper to build full URL from baseURL and path
   // Playwright's goto with absolute paths (like '/modules') ignores baseURL's path portion
   // So we need to manually construct the full URL
@@ -223,44 +201,35 @@ test.describe('CSS styles in SSR (dev mode)', () => {
     // Start from home
     await page.goto(buildUrl(baseURL!, '/'))
 
-    // Verify initial styles with retry to handle potential Vite dep optimization reload
+    // Verify initial styles
     const globalElement = page.getByTestId('global-styled')
-    await expect(async () => {
-      await expect(globalElement).toBeVisible()
-      const backgroundColor = await globalElement.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(59, 130, 246)')
-    }).toPass({ timeout: 10000 })
+    await expect(globalElement).toBeVisible()
+    let backgroundColor = await globalElement.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(59, 130, 246)')
 
     // Navigate to modules page
     await page.getByTestId('nav-modules').click()
-    // Use glob pattern to match with or without basepath
     await page.waitForURL('**/modules')
 
-    // Verify CSS modules styles with retry to handle potential Vite dep optimization reload
+    // Verify CSS modules styles
     const card = page.getByTestId('module-card')
-    await expect(async () => {
-      await expect(card).toBeVisible()
-      const backgroundColor = await card.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(240, 253, 244)')
-    }).toPass({ timeout: 10000 })
+    await expect(card).toBeVisible()
+    backgroundColor = await card.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(240, 253, 244)')
 
     // Navigate back to home
     await page.getByTestId('nav-home').click()
-    // Match home URL with or without trailing slash and optional query string
-    // Matches: /, /?, /my-app, /my-app/, /my-app?foo=bar
     await page.waitForURL(/\/([^/]*)(\/)?($|\?)/)
 
-    // Verify global styles still work with retry
-    await expect(async () => {
-      await expect(globalElement).toBeVisible()
-      const backgroundColor = await globalElement.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(59, 130, 246)')
-    }).toPass({ timeout: 10000 })
+    // Verify global styles still work
+    await expect(globalElement).toBeVisible()
+    backgroundColor = await globalElement.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(59, 130, 246)')
   })
 })
diff --git a/e2e/react-start/css-modules/tests/setup/global.setup.ts b/e2e/react-start/css-modules/tests/setup/global.setup.ts
index 3593d10ab90..413c460f56f 100644
--- a/e2e/react-start/css-modules/tests/setup/global.setup.ts
+++ b/e2e/react-start/css-modules/tests/setup/global.setup.ts
@@ -1,6 +1,77 @@
-import { e2eStartDummyServer } from '@tanstack/router-e2e-utils'
+import { chromium } from '@playwright/test'
+import {
+  e2eStartDummyServer,
+  getTestServerPort,
+} from '@tanstack/router-e2e-utils'
 import packageJson from '../../package.json' with { type: 'json' }
 
+async function waitForServer(url: string) {
+  const start = Date.now()
+  while (Date.now() - start < 30_000) {
+    try {
+      const res = await fetch(url, { redirect: 'manual' })
+      if (res.ok) return
+    } catch {
+      // ignore
+    }
+    await new Promise((r) => setTimeout(r, 250))
+  }
+  throw new Error(`Timed out waiting for dev server at ${url}`)
+}
+
+async function preOptimizeDevServer(baseURL: string) {
+  const browser = await chromium.launch()
+  const context = await browser.newContext()
+  const page = await context.newPage()
+
+  try {
+    await page.goto(`${baseURL}/`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('global-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/modules`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('module-card').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/sass-mixin`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('mixin-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/quotes`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('quote-styled').waitFor({ state: 'visible' })
+    await page.getByTestId('after-quote-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    // Ensure we end in a stable state. Vite's optimize step triggers a reload;
+    // this waits until no further navigations happen for a short window.
+    for (let i = 0; i < 40; i++) {
+      const currentUrl = page.url()
+      await page.waitForTimeout(250)
+      if (page.url() === currentUrl) {
+        await page.waitForTimeout(250)
+        if (page.url() === currentUrl) return
+      }
+    }
+
+    throw new Error('Dev server did not reach a stable URL after warmup')
+  } finally {
+    await context.close()
+    await browser.close()
+  }
+}
+
 export default async function setup() {
   await e2eStartDummyServer(packageJson.name)
+
+  if (process.env.MODE !== 'dev') return
+
+  const viteConfig = process.env.VITE_CONFIG // 'nitro' | 'basepath' | 'cloudflare' | undefined
+  const port = await getTestServerPort(
+    viteConfig ? `${packageJson.name}-${viteConfig}` : packageJson.name,
+  )
+  const basePath = viteConfig === 'basepath' ? '/my-app' : ''
+  const baseURL = `http://localhost:${port}${basePath}`
+
+  await waitForServer(baseURL)
+  await preOptimizeDevServer(baseURL)
 }
diff --git a/e2e/solid-start/css-modules/tests/css.spec.ts b/e2e/solid-start/css-modules/tests/css.spec.ts
index 0a83800fded..0b34d9e6516 100644
--- a/e2e/solid-start/css-modules/tests/css.spec.ts
+++ b/e2e/solid-start/css-modules/tests/css.spec.ts
@@ -12,28 +12,6 @@ const whitelistErrors = [
 test.describe('CSS styles in SSR (dev mode)', () => {
   test.use({ whitelistErrors })
 
-  // Warmup: trigger Vite's dependency optimization before running tests
-  // This prevents "optimized dependencies changed. reloading" during actual tests
-  // We use a real browser context since dep optimization happens on JS load, not HTTP requests
-  test.beforeAll(async ({ browser, baseURL }) => {
-    const context = await browser.newContext()
-    const page = await context.newPage()
-    try {
-      // Load both pages to trigger dependency optimization
-      await page.goto(baseURL!)
-      await page.waitForTimeout(2000) // Wait for deps to optimize
-      await page.goto(`${baseURL}/modules`)
-      await page.waitForTimeout(2000)
-      // Load again after optimization completes
-      await page.goto(baseURL!)
-      await page.waitForTimeout(1000)
-    } catch {
-      // Ignore errors during warmup
-    } finally {
-      await context.close()
-    }
-  })
-
   // Helper to build full URL from baseURL and path
   // Playwright's goto with absolute paths (like '/modules') ignores baseURL's path portion
   // So we need to manually construct the full URL
@@ -195,44 +173,35 @@ test.describe('CSS styles in SSR (dev mode)', () => {
     // Start from home
     await page.goto(buildUrl(baseURL!, '/'))
 
-    // Verify initial styles with retry to handle potential Vite dep optimization reload
+    // Verify initial styles
     const globalElement = page.getByTestId('global-styled')
-    await expect(async () => {
-      await expect(globalElement).toBeVisible()
-      const backgroundColor = await globalElement.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(59, 130, 246)')
-    }).toPass({ timeout: 10000 })
+    await expect(globalElement).toBeVisible()
+    let backgroundColor = await globalElement.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(59, 130, 246)')
 
     // Navigate to modules page
     await page.getByTestId('nav-modules').click()
-    // Use glob pattern to match with or without basepath
     await page.waitForURL('**/modules')
 
-    // Verify CSS modules styles with retry to handle potential Vite dep optimization reload
+    // Verify CSS modules styles
     const card = page.getByTestId('module-card')
-    await expect(async () => {
-      await expect(card).toBeVisible()
-      const backgroundColor = await card.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(240, 253, 244)')
-    }).toPass({ timeout: 10000 })
+    await expect(card).toBeVisible()
+    backgroundColor = await card.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(240, 253, 244)')
 
     // Navigate back to home
     await page.getByTestId('nav-home').click()
-    // Match home URL with or without trailing slash and optional query string
-    // Matches: /, /?, /my-app, /my-app/, /my-app?foo=bar
     await page.waitForURL(/\/([^/]*)(\/)?($|\?)/)
 
-    // Verify global styles still work with retry
-    await expect(async () => {
-      await expect(globalElement).toBeVisible()
-      const backgroundColor = await globalElement.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(59, 130, 246)')
-    }).toPass({ timeout: 10000 })
+    // Verify global styles still work
+    await expect(globalElement).toBeVisible()
+    backgroundColor = await globalElement.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(59, 130, 246)')
   })
 })
diff --git a/e2e/solid-start/css-modules/tests/setup/global.setup.ts b/e2e/solid-start/css-modules/tests/setup/global.setup.ts
index 3593d10ab90..eaf5091c740 100644
--- a/e2e/solid-start/css-modules/tests/setup/global.setup.ts
+++ b/e2e/solid-start/css-modules/tests/setup/global.setup.ts
@@ -1,6 +1,68 @@
-import { e2eStartDummyServer } from '@tanstack/router-e2e-utils'
+import { chromium } from '@playwright/test'
+import {
+  e2eStartDummyServer,
+  getTestServerPort,
+} from '@tanstack/router-e2e-utils'
 import packageJson from '../../package.json' with { type: 'json' }
 
+async function waitForServer(url: string) {
+  const start = Date.now()
+  while (Date.now() - start < 30_000) {
+    try {
+      const res = await fetch(url, { redirect: 'manual' })
+      if (res.ok) return
+    } catch {
+      // ignore
+    }
+    await new Promise((r) => setTimeout(r, 250))
+  }
+  throw new Error(`Timed out waiting for dev server at ${url}`)
+}
+
+async function preOptimizeDevServer(baseURL: string) {
+  const browser = await chromium.launch()
+  const context = await browser.newContext()
+  const page = await context.newPage()
+
+  try {
+    await page.goto(`${baseURL}/`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('global-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/modules`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('module-card').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/sass-mixin`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('mixin-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    // Ensure we end in a stable state. Vite's optimize step triggers a reload;
+    // this waits until no further navigations happen for a short window.
+    for (let i = 0; i < 40; i++) {
+      const currentUrl = page.url()
+      await page.waitForTimeout(250)
+      if (page.url() === currentUrl) {
+        await page.waitForTimeout(250)
+        if (page.url() === currentUrl) return
+      }
+    }
+
+    throw new Error('Dev server did not reach a stable URL after warmup')
+  } finally {
+    await context.close()
+    await browser.close()
+  }
+}
+
 export default async function setup() {
   await e2eStartDummyServer(packageJson.name)
+
+  if (process.env.MODE !== 'dev') return
+
+  const port = await getTestServerPort(packageJson.name)
+  const baseURL = `http://localhost:${port}`
+
+  await waitForServer(baseURL)
+  await preOptimizeDevServer(baseURL)
 }
diff --git a/e2e/vue-start/css-modules/tests/css.spec.ts b/e2e/vue-start/css-modules/tests/css.spec.ts
index f3d06bcb1c0..7646eb750eb 100644
--- a/e2e/vue-start/css-modules/tests/css.spec.ts
+++ b/e2e/vue-start/css-modules/tests/css.spec.ts
@@ -14,28 +14,6 @@ const whitelistErrors = [
 test.describe('CSS styles in SSR (dev mode)', () => {
   test.use({ whitelistErrors })
 
-  // Warmup: trigger Vite's dependency optimization before running tests
-  // This prevents "optimized dependencies changed. reloading" during actual tests
-  // We use a real browser context since dep optimization happens on JS load, not HTTP requests
-  test.beforeAll(async ({ browser, baseURL }) => {
-    const context = await browser.newContext()
-    const page = await context.newPage()
-    try {
-      // Load both pages to trigger dependency optimization
-      await page.goto(baseURL!)
-      await page.waitForTimeout(2000) // Wait for deps to optimize
-      await page.goto(`${baseURL}/modules`)
-      await page.waitForTimeout(2000)
-      // Load again after optimization completes
-      await page.goto(baseURL!)
-      await page.waitForTimeout(1000)
-    } catch {
-      // Ignore errors during warmup
-    } finally {
-      await context.close()
-    }
-  })
-
   // Helper to build full URL from baseURL and path
   // Playwright's goto with absolute paths (like '/modules') ignores baseURL's path portion
   // So we need to manually construct the full URL
@@ -197,44 +175,35 @@ test.describe('CSS styles in SSR (dev mode)', () => {
     // Start from home
     await page.goto(buildUrl(baseURL!, '/'))
 
-    // Verify initial styles with retry to handle potential Vite dep optimization reload
+    // Verify initial styles
     const globalElement = page.getByTestId('global-styled')
-    await expect(async () => {
-      await expect(globalElement).toBeVisible()
-      const backgroundColor = await globalElement.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(59, 130, 246)')
-    }).toPass({ timeout: 10000 })
+    await expect(globalElement).toBeVisible()
+    let backgroundColor = await globalElement.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(59, 130, 246)')
 
     // Navigate to modules page
     await page.getByTestId('nav-modules').click()
-    // Use glob pattern to match with or without basepath
     await page.waitForURL('**/modules')
 
-    // Verify CSS modules styles with retry to handle potential Vite dep optimization reload
+    // Verify CSS modules styles
     const card = page.getByTestId('module-card')
-    await expect(async () => {
-      await expect(card).toBeVisible()
-      const backgroundColor = await card.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(240, 253, 244)')
-    }).toPass({ timeout: 10000 })
+    await expect(card).toBeVisible()
+    backgroundColor = await card.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(240, 253, 244)')
 
     // Navigate back to home
     await page.getByTestId('nav-home').click()
-    // Match home URL with or without trailing slash and optional query string
-    // Matches: /, /?, /my-app, /my-app/, /my-app?foo=bar
     await page.waitForURL(/\/([^/]*)(\/)?($|\?)/)
 
-    // Verify global styles still work with retry
-    await expect(async () => {
-      await expect(globalElement).toBeVisible()
-      const backgroundColor = await globalElement.evaluate(
-        (el) => getComputedStyle(el).backgroundColor,
-      )
-      expect(backgroundColor).toBe('rgb(59, 130, 246)')
-    }).toPass({ timeout: 10000 })
+    // Verify global styles still work
+    await expect(globalElement).toBeVisible()
+    backgroundColor = await globalElement.evaluate(
+      (el) => getComputedStyle(el).backgroundColor,
+    )
+    expect(backgroundColor).toBe('rgb(59, 130, 246)')
   })
 })
diff --git a/e2e/vue-start/css-modules/tests/setup/global.setup.ts b/e2e/vue-start/css-modules/tests/setup/global.setup.ts
index 3593d10ab90..eaf5091c740 100644
--- a/e2e/vue-start/css-modules/tests/setup/global.setup.ts
+++ b/e2e/vue-start/css-modules/tests/setup/global.setup.ts
@@ -1,6 +1,68 @@
-import { e2eStartDummyServer } from '@tanstack/router-e2e-utils'
+import { chromium } from '@playwright/test'
+import {
+  e2eStartDummyServer,
+  getTestServerPort,
+} from '@tanstack/router-e2e-utils'
 import packageJson from '../../package.json' with { type: 'json' }
 
+async function waitForServer(url: string) {
+  const start = Date.now()
+  while (Date.now() - start < 30_000) {
+    try {
+      const res = await fetch(url, { redirect: 'manual' })
+      if (res.ok) return
+    } catch {
+      // ignore
+    }
+    await new Promise((r) => setTimeout(r, 250))
+  }
+  throw new Error(`Timed out waiting for dev server at ${url}`)
+}
+
+async function preOptimizeDevServer(baseURL: string) {
+  const browser = await chromium.launch()
+  const context = await browser.newContext()
+  const page = await context.newPage()
+
+  try {
+    await page.goto(`${baseURL}/`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('global-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/modules`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('module-card').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    await page.goto(`${baseURL}/sass-mixin`, { waitUntil: 'domcontentloaded' })
+    await page.getByTestId('mixin-styled').waitFor({ state: 'visible' })
+    await page.waitForLoadState('networkidle')
+
+    // Ensure we end in a stable state. Vite's optimize step triggers a reload;
+    // this waits until no further navigations happen for a short window.
+    for (let i = 0; i < 40; i++) {
+      const currentUrl = page.url()
+      await page.waitForTimeout(250)
+      if (page.url() === currentUrl) {
+        await page.waitForTimeout(250)
+        if (page.url() === currentUrl) return
+      }
+    }
+
+    throw new Error('Dev server did not reach a stable URL after warmup')
+  } finally {
+    await context.close()
+    await browser.close()
+  }
+}
+
 export default async function setup() {
   await e2eStartDummyServer(packageJson.name)
+
+  if (process.env.MODE !== 'dev') return
+
+  const port = await getTestServerPort(packageJson.name)
+  const baseURL = `http://localhost:${port}`
+
+  await waitForServer(baseURL)
+  await preOptimizeDevServer(baseURL)
 }