diff --git a/e2e/tests/api-auth.spec.ts b/e2e/tests/api-auth.spec.ts
new file mode 100644
index 0000000..c43df45
--- /dev/null
+++ b/e2e/tests/api-auth.spec.ts
@@ -0,0 +1,29 @@
+import { test, expect } from "@playwright/test";
+
+// No page/cookies involved -- confirms protected routes actually reject
+// unauthenticated requests, independent of whatever the UI does.
+test.describe("unauthenticated API access is rejected", () => {
+  for (const path of ["/api/hosts", "/api/devices", "/api/auth/me"]) {
+    test(`GET ${path} without a session returns 401`, async ({ request }) => {
+      const res = await request.get(path);
+      expect(res.status()).toBe(401);
+    });
+  }
+
+  test("POST /api/auth/login with bad credentials returns 401 and grants no access", async ({
+    request,
+  }) => {
+    const res = await request.post("/api/auth/login", {
+      data: { username: "admin", password: "definitely-not-the-password" },
+    });
+    expect(res.status()).toBe(401);
+
+    // @fastify/session issues an anonymous session cookie on any response by
+    // design (regardless of login success) -- that alone doesn't mean anything.
+    // What matters is that cookie doesn't carry authentication: the same
+    // request context (Playwright persists cookies across calls) must still
+    // be rejected from a protected route.
+    const hostsRes = await request.get("/api/hosts");
+    expect(hostsRes.status()).toBe(401);
+  });
+});
diff --git a/e2e/tests/local-login.spec.ts b/e2e/tests/local-login.spec.ts
index 0f6ceea..490e437 100644
--- a/e2e/tests/local-login.spec.ts
+++ b/e2e/tests/local-login.spec.ts
@@ -19,3 +19,32 @@ test("local username/password login and logout", async ({ page }) => {
   await page.getByRole("button", { name: "Sign out" }).click();
   await expect(page.getByPlaceholder("Username")).toBeVisible();
 });
+
+test("wrong password is rejected with an error, no session", async ({ page }) => {
+  await page.goto("/");
+  await page.getByPlaceholder("Username").fill(USERNAME);
+  await page.getByPlaceholder("Password").fill("definitely-not-the-password");
+  await page.getByRole("button", { name: "Sign in" }).click();
+
+  await expect(page.getByText(/invalid credentials/i)).toBeVisible();
+  // Still on the login form, not the dashboard.
+  await expect(page.getByPlaceholder("Username")).toBeVisible();
+  await expect(page.locator(".host-card")).toHaveCount(0);
+});
+
+test("session persists across a page reload", async ({ page }) => {
+  test.skip(!PASSWORD, "LOCAL_PASSWORD not set");
+
+  await page.goto("/");
+  await page.getByPlaceholder("Username").fill(USERNAME);
+  await page.getByPlaceholder("Password").fill(PASSWORD);
+  await page.getByRole("button", { name: "Sign in" }).click();
+  await expect(page.locator(".host-card").first()).toBeVisible({ timeout: 15_000 });
+
+  await page.reload();
+
+  await expect(page.getByText(USERNAME)).toBeVisible();
+  await expect(page.locator(".host-card").first()).toBeVisible({ timeout: 15_000 });
+
+  await page.getByRole("button", { name: "Sign out" }).click();
+});
diff --git a/e2e/tests/oidc-login.spec.ts b/e2e/tests/oidc-login.spec.ts
index 1594cea..606f16b 100644
--- a/e2e/tests/oidc-login.spec.ts
+++ b/e2e/tests/oidc-login.spec.ts
@@ -33,3 +33,21 @@ test("OIDC login via Authentik stays on public domains throughout", async ({ pag
   await page.getByRole("button", { name: "Sign out" }).click();
   await expect(page.getByPlaceholder("Username")).toBeVisible();
 });
+
+test("wrong Authentik password does not reach the dashboard", async ({ page }) => {
+  test.skip(!PASSWORD, "OIDC_PASSWORD not set");
+
+  await page.goto("/");
+  await page.getByRole("link", { name: "Sign in with Authentik" }).click();
+  await page.waitForURL(/^https:\/\/auth\.jerodrigged\.com\//, { timeout: 10_000 });
+
+  await page.getByPlaceholder(/email or username/i).fill(USERNAME);
+  await page.getByRole("button", { name: /log in|continue|next/i }).click();
+
+  await page.getByPlaceholder(/password/i).fill("definitely-not-the-password");
+  await page.getByRole("button", { name: /log in|continue|sign in/i }).click();
+
+  // Authentik re-shows the password stage with an error, never redirects back.
+  await expect(page.getByText(/failed|invalid|incorrect/i)).toBeVisible({ timeout: 10_000 });
+  expect(page.url()).toMatch(/^https:\/\/auth\.jerodrigged\.com\//);
+});