diff --git a/.circleci/config.yml b/.circleci/config.yml
index a8a33335ad..dbeb412506 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -2690,6 +2690,122 @@ jobs:
           path: ui/litellm-dashboard/playwright-report
           destination: e2e-playwright-report
 
+  e2e_ui_testing_server_root_path:
+    docker:
+      - image: cimg/python:3.12-browsers@sha256:b432899af01c9a311bf74f4f22e9ada2e5306d4b1b4383f8d29e1228a5844ef2
+        auth:
+          username: ${DOCKERHUB_USERNAME}
+          password: ${DOCKERHUB_PASSWORD}
+      - image: cimg/postgres:16.0@sha256:b125148bc76e8e8eee5eb3ad6020a3a14110a14e8192f1c645128afebe2e2f84
+        environment:
+          POSTGRES_USER: e2euser
+          POSTGRES_PASSWORD: e2epassword
+          POSTGRES_DB: litellm_e2e
+    resource_class: large
+    working_directory: ~/project
+    environment:
+      DATABASE_URL: "postgresql://e2euser:e2epassword@localhost:5432/litellm_e2e"
+      CI: "true"
+      # The whole job exercises the proxy mounted under a prefix. SERVER_ROOT_PATH
+      # is read both by the proxy at boot (to rewrite the built UI bundle in place)
+      # and by migration.serverRootPath.config.ts, which refuses to run without it.
+      SERVER_ROOT_PATH: "/litellm"
+    steps:
+      - checkout
+      - setup_google_dns
+      - install_uv
+      - restore_cache:
+          keys:
+            - v1-uv-cache-{{ checksum "uv.lock" }}
+      - run:
+          name: Install Python dependencies
+          command: |
+            uv sync --frozen --all-groups --all-extras --python 3.12
+            uv run --no-sync python -m prisma generate --schema litellm/proxy/schema.prisma
+      - save_cache:
+          key: v1-uv-cache-{{ checksum "uv.lock" }}
+          paths:
+            - ~/.cache/uv
+      - restore_cache:
+          keys:
+            - ui-e2e-node-deps-v2-{{ checksum "ui/litellm-dashboard/package-lock.json" }}
+      - run:
+          name: Install Node dependencies and Playwright
+          command: |
+            cd ui/litellm-dashboard
+            npm ci
+            npx playwright install chromium
+      - save_cache:
+          key: ui-e2e-node-deps-v2-{{ checksum "ui/litellm-dashboard/package-lock.json" }}
+          paths:
+            - ui/litellm-dashboard/node_modules
+            - ~/.cache/ms-playwright
+      - run:
+          name: Build UI from source
+          command: |
+            cd ui/litellm-dashboard
+            npm run build
+            rm -rf ../../litellm/proxy/_experimental/out
+            mv out ../../litellm/proxy/_experimental/out
+            find ../../litellm/proxy/_experimental/out -name '*.html' ! -name 'index.html' | while read -r f; do
+              d="${f%.html}"; mkdir -p "$d"; mv "$f" "$d/index.html"
+            done
+      - wait_for_service:
+          url: tcp://localhost:5432
+          timeout: "30"
+      - run:
+          name: Push Prisma schema
+          command: uv run --no-sync python -m prisma db push --schema litellm/proxy/schema.prisma --accept-data-loss
+      - run:
+          name: Seed database
+          command: |
+            PGPASSWORD=e2epassword psql -h localhost -p 5432 -U e2euser -d litellm_e2e \
+              -f ui/litellm-dashboard/e2e_tests/fixtures/seed.sql
+      - run:
+          name: Start mock LLM server
+          command: uv run --no-sync python ui/litellm-dashboard/e2e_tests/fixtures/mock_llm_server/server.py
+          background: true
+      - run:
+          name: Start LiteLLM proxy under a server root path
+          environment:
+            LITELLM_MASTER_KEY: "sk-1234"
+            MOCK_LLM_URL: "http://127.0.0.1:8090/v1"
+            DISABLE_SCHEMA_UPDATE: "true"
+          # Output flows to this step's own log, so a boot crash is visible here
+          # rather than swallowed by a downstream readiness probe.
+          command: |
+            LITELLM_LICENSE="$LITELLM_LICENSE" \
+              uv run --no-sync python -m litellm.proxy.proxy_cli \
+                --config ui/litellm-dashboard/e2e_tests/fixtures/config.yml \
+                --port 4000
+          background: true
+      - run:
+          name: Wait for prefixed proxy to be ready
+          command: |
+            for i in $(seq 1 60); do
+              HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" --max-time 5 -H "Authorization: Bearer sk-1234" http://127.0.0.1:4000/litellm/health 2>/dev/null || true)
+              if [ "$HTTP_CODE" = "200" ]; then
+                echo "Prefixed proxy is ready"
+                exit 0
+              fi
+              sleep 2
+            done
+            echo "Prefixed proxy failed to start; see the 'Start LiteLLM proxy under a server root path' step for the boot log"
+            exit 1
+      - run:
+          name: Run migration smoke under SERVER_ROOT_PATH
+          command: |
+            cd ui/litellm-dashboard
+            LITELLM_LICENSE="$LITELLM_LICENSE" \
+              npx playwright test --config e2e_tests/migration.serverRootPath.config.ts
+          no_output_timeout: 10m
+      - store_artifacts:
+          path: ui/litellm-dashboard/test-results
+          destination: e2e-server-root-path-test-results
+      - store_artifacts:
+          path: ui/litellm-dashboard/playwright-report
+          destination: e2e-server-root-path-playwright-report
+
   build_docker_database_image:
     machine:
       image: ubuntu-2204:2024.04.1
@@ -2795,6 +2911,8 @@ workflows:
           filters: *main_branches
       - e2e_ui_testing:
           filters: *main_branches
+      - e2e_ui_testing_server_root_path:
+          filters: *main_branches
       - build_and_test:
           requires:
             - build_docker_database_image
diff --git a/ui/litellm-dashboard/e2e_tests/fixtures/migratedPages.ts b/ui/litellm-dashboard/e2e_tests/fixtures/migratedPages.ts
new file mode 100644
index 0000000000..f2ba66147e
--- /dev/null
+++ b/ui/litellm-dashboard/e2e_tests/fixtures/migratedPages.ts
@@ -0,0 +1,16 @@
+/**
+ * Source of truth for the App Router migration smoke (tests/migration/migratedPages.spec.ts).
+ *
+ * Add a route segment here once its migration has MERGED to the branch under test.
+ * Both suites pick it up automatically:
+ *   - default mount:           npm run e2e:migration
+ *   - server-root-path mount:  SERVER_ROOT_PATH=/<root> npm run e2e:migration:root
+ *
+ * Keep this in lockstep with MIGRATED_PAGES in src/utils/migratedPages.ts.
+ * Pending (uncomment as each PR lands): playground, and the leaf-pages batch
+ * (budgets, caching, cost-tracking, guardrails, guardrails-monitor, logs,
+ * mcp-servers, memory, policies, projects, prompts, search-tools, skills,
+ * tag-management, tool-policies, transform-request, ui-theme, vector-stores,
+ * workflows, access-groups).
+ */
+export const MIGRATED_E2E_SEGMENTS: string[] = ["api-reference"];
diff --git a/ui/litellm-dashboard/e2e_tests/globalSetup.ts b/ui/litellm-dashboard/e2e_tests/globalSetup.ts
index 8f80f57bd7..0b3fa7e880 100644
--- a/ui/litellm-dashboard/e2e_tests/globalSetup.ts
+++ b/ui/litellm-dashboard/e2e_tests/globalSetup.ts
@@ -4,17 +4,18 @@ import * as fs from "fs";
 
 async function globalSetup() {
   const browser = await chromium.launch();
+  const rootPath = process.env.SERVER_ROOT_PATH ?? "";
 
   for (const role of Object.values(Role)) {
     const { email, password } = users[role];
     const storagePath = STORAGE_PATHS[role];
     const page = await browser.newPage();
     try {
-      await page.goto("http://localhost:4000/ui/login");
+      await page.goto(`http://localhost:4000${rootPath}/ui/login`);
       await page.getByPlaceholder("Enter your username").fill(email);
       await page.getByPlaceholder("Enter your password").fill(password);
       await page.getByRole("button", { name: "Login", exact: true }).click();
-      await page.waitForURL((url) => url.pathname.startsWith("/ui") && !url.pathname.includes("/login"), {
+      await page.waitForURL((url) => url.pathname.startsWith(`${rootPath}/ui`) && !url.pathname.includes("/login"), {
         timeout: 30_000,
       });
       await expect(page.locator("a", { hasText: "Virtual Keys" })).toBeVisible({ timeout: 30_000 });
diff --git a/ui/litellm-dashboard/e2e_tests/migration.serverRootPath.config.ts b/ui/litellm-dashboard/e2e_tests/migration.serverRootPath.config.ts
new file mode 100644
index 0000000000..205348463c
--- /dev/null
+++ b/ui/litellm-dashboard/e2e_tests/migration.serverRootPath.config.ts
@@ -0,0 +1,38 @@
+import { defineConfig, devices } from "@playwright/test";
+
+/**
+ * App Router migration smoke under a non-root mount. Boot the proxy with the same
+ * SERVER_ROOT_PATH (e.g. SERVER_ROOT_PATH=/litellm) and a UI built for it before
+ * running. globalSetup logs in at `${SERVER_ROOT_PATH}/ui/login` so the admin
+ * storage state is valid under the prefix.
+ */
+if (!process.env.SERVER_ROOT_PATH) {
+  throw new Error(
+    "migration.serverRootPath.config.ts requires SERVER_ROOT_PATH to be set (e.g. SERVER_ROOT_PATH=/litellm). " +
+      "Without it this config silently re-runs the default mount and never exercises the prefix. " +
+      "For the root-less run use the default playwright.config.ts (npm run e2e:migration).",
+  );
+}
+
+export default defineConfig({
+  testDir: "./tests/migration",
+  testMatch: ["migratedPages.spec.ts"],
+  fullyParallel: true,
+  forbidOnly: !!process.env.CI,
+  retries: process.env.CI ? 2 : 0,
+  workers: process.env.CI ? 1 : undefined,
+  reporter: "list",
+  use: {
+    baseURL: "http://localhost:4000",
+    trace: "on-first-retry",
+    actionTimeout: 15 * 1000,
+    navigationTimeout: 30 * 1000,
+    launchOptions: {
+      slowMo: process.env.SLOWMO ? parseInt(process.env.SLOWMO, 10) || 0 : 0,
+    },
+  },
+  projects: [{ name: "chromium", use: { ...devices["Desktop Chrome"] } }],
+  timeout: 3 * 60 * 1000,
+  expect: { timeout: 10 * 1000 },
+  globalSetup: require.resolve("./globalSetup"),
+});
diff --git a/ui/litellm-dashboard/e2e_tests/tests/migration/README.md b/ui/litellm-dashboard/e2e_tests/tests/migration/README.md
new file mode 100644
index 0000000000..4b3a391d42
--- /dev/null
+++ b/ui/litellm-dashboard/e2e_tests/tests/migration/README.md
@@ -0,0 +1,33 @@
+# App Router migration smoke
+
+A growing E2E smoke for pages migrated from the legacy `?page=` switch to App
+Router path routes. For each migrated page it clicks the page's sidebar link, checks
+the URL is the path route and the page renders, reloads it, then clicks off to a
+legacy page and back to confirm navigation still works. It runs in two situations:
+the default mount and a non-root `SERVER_ROOT_PATH` mount.
+
+## Adding a page
+
+When a page's migration merges, add its route segment to
+`e2e_tests/fixtures/migratedPages.ts` (keep it in lockstep with `MIGRATED_PAGES`
+in `src/utils/migratedPages.ts`). Both suites pick it up automatically.
+
+## Running
+
+Build the UI into the proxy and start the proxy first (the suite runs against
+`http://localhost:4000`).
+
+Default mount:
+
+```
+npm run e2e:migration
+```
+
+Non-root mount (build and boot the proxy with the same root path, e.g. `/litellm`):
+
+```
+SERVER_ROOT_PATH=/litellm npm run e2e:migration:root
+```
+
+`globalSetup` logs in once per role; the admin storage state is reused for these
+tests. Under a non-root mount it logs in at `${SERVER_ROOT_PATH}/ui/login`.
diff --git a/ui/litellm-dashboard/e2e_tests/tests/migration/migratedPages.spec.ts b/ui/litellm-dashboard/e2e_tests/tests/migration/migratedPages.spec.ts
new file mode 100644
index 0000000000..98f4fee145
--- /dev/null
+++ b/ui/litellm-dashboard/e2e_tests/tests/migration/migratedPages.spec.ts
@@ -0,0 +1,101 @@
+import { test, expect, type Page } from "@playwright/test";
+import { MIGRATED_E2E_SEGMENTS } from "../../fixtures/migratedPages";
+import { ADMIN_STORAGE_PATH } from "../../constants";
+import { dismissFeedbackPopup } from "../../helpers/navigation";
+
+/**
+ * App Router migration smoke as a user journey: start where the proxy lands you,
+ * click a migrated page in the sidebar, confirm it routed and rendered, reload it
+ * (the check a wrong server_root_path breaks), bounce to a legacy page and back,
+ * and, once two pages are migrated, navigate directly between two migrated pages.
+ *
+ * Driven by MIGRATED_E2E_SEGMENTS, so it grows as pages are migrated. Set
+ * SERVER_ROOT_PATH (e.g. "/litellm") to exercise the non-root mount; leave it
+ * unset for the default mount. Boot the proxy with the matching value first.
+ */
+const ROOT = process.env.SERVER_ROOT_PATH ?? "";
+
+const esc = (s: string) => s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+const pathRe = (segment: string) => new RegExp(`${esc(ROOT)}/ui/${esc(segment)}/?($|\\?)`);
+const legacyAnchor = (page: Page) => page.locator("a", { hasText: "Virtual Keys" });
+
+/** The dashboard shell is present (sidebar rendered); page didn't 404 / crash. */
+async function expectRendered(page: Page) {
+  await expect(legacyAnchor(page)).toBeVisible({ timeout: 20_000 });
+}
+
+/**
+ * Click a migrated page's sidebar link. Migrated items render as <a href=".../ui/<segment>">;
+ * nested ones live under collapsible submenus, so expand submenus until the link is clickable.
+ */
+async function clickSidebar(page: Page, segment: string) {
+  const link = page.locator(`a[href$="/ui/${segment}"]`).first();
+  for (let i = 0; i < 8 && !(await link.isVisible().catch(() => false)); i++) {
+    const collapsedSubmenu = page
+      .locator(".ant-menu-submenu:not(.ant-menu-submenu-open) > .ant-menu-submenu-title")
+      .first();
+    if (!(await collapsedSubmenu.isVisible().catch(() => false))) break;
+    await collapsedSubmenu.click();
+    await page.waitForTimeout(250);
+  }
+  await link.click();
+}
+
+test.use({ storageState: ADMIN_STORAGE_PATH });
+
+test.describe("App Router migrated pages", () => {
+  for (const segment of MIGRATED_E2E_SEGMENTS) {
+    test(`${segment}: sidebar nav, reload, and round-trip with a legacy page`, async ({ page }) => {
+      const pageErrors: string[] = [];
+      page.on("pageerror", (e) => pageErrors.push(String(e)));
+
+      // 1. Start where the proxy lands us.
+      await page.goto(`${ROOT}/ui/`);
+      await dismissFeedbackPopup(page);
+      await expectRendered(page);
+
+      // 2. Click the migrated page in the sidebar -> path route + rendered.
+      await clickSidebar(page, segment);
+      await expect(page).toHaveURL(pathRe(segment));
+      await expectRendered(page);
+      // 3. Reload the path route directly; a wrong server_root_path 404s here.
+      await page.reload();
+      await dismissFeedbackPopup(page);
+      await expect(page).toHaveURL(pathRe(segment));
+      await expectRendered(page);
+      // 4. Click off to a legacy (not-yet-migrated) page.
+      await legacyAnchor(page).click();
+      await expect(page).toHaveURL(new RegExp(`${esc(ROOT)}/ui/\\?page=api-keys`));
+      await dismissFeedbackPopup(page);
+      await expectRendered(page);
+      // 5. Click back to the migrated page.
+      await clickSidebar(page, segment);
+      await expect(page).toHaveURL(pathRe(segment));
+      await expectRendered(page);
+      expect(pageErrors, `page errors during ${segment} journey`).toEqual([]);
+    });
+  }
+
+  test("navigates directly between two migrated pages", async ({ page }) => {
+    test.skip(MIGRATED_E2E_SEGMENTS.length < 2, "needs >= 2 migrated pages");
+    const [first, second] = MIGRATED_E2E_SEGMENTS;
+    const pageErrors: string[] = [];
+    page.on("pageerror", (e) => pageErrors.push(String(e)));
+
+    await page.goto(`${ROOT}/ui/`);
+    await dismissFeedbackPopup(page);
+
+    await clickSidebar(page, first);
+    await expect(page).toHaveURL(pathRe(first));
+    await expectRendered(page);
+    await clickSidebar(page, second);
+    await expect(page).toHaveURL(pathRe(second));
+    await expectRendered(page);
+    // Back to the first migrated page.
+    await clickSidebar(page, first);
+    await expect(page).toHaveURL(pathRe(first));
+    await expectRendered(page);
+
+    expect(pageErrors, "page errors during migrated -> migrated nav").toEqual([]);
+  });
+});
diff --git a/ui/litellm-dashboard/package.json b/ui/litellm-dashboard/package.json
index 623389e76e..c9795cf7c6 100644
--- a/ui/litellm-dashboard/package.json
+++ b/ui/litellm-dashboard/package.json
@@ -16,6 +16,8 @@
     "format:check": "prettier --check .",
     "e2e": "playwright test --config e2e_tests/playwright.config.ts",
     "e2e:ui": "playwright test --ui --config e2e_tests/playwright.config.ts",
+    "e2e:migration": "playwright test e2e_tests/tests/migration/migratedPages.spec.ts --config e2e_tests/playwright.config.ts",
+    "e2e:migration:root": "playwright test --config e2e_tests/migration.serverRootPath.config.ts",
     "knip": "knip",
     "knip:fix": "knip --fix",
     "gen:api": "node scripts/gen-api-types.mjs"