diff --git a/src/db/tables/featureFlags.ts b/src/db/tables/featureFlags.ts
index 136b396c14..af03ea7ee1 100644
--- a/src/db/tables/featureFlags.ts
+++ b/src/db/tables/featureFlags.ts
@@ -5,6 +5,7 @@
 import createDbConnection from "../connect";
 import { logger } from "../../app/functions/server/logging";
 import { FeatureFlagRow } from "knex/types/tables";
+import { headers } from "next/headers";
 
 const knex = createDbConnection();
 
@@ -76,11 +77,26 @@ export async function getEnabledFeatureFlags(
       return void subQuery;
     });
 
-  const enabledFlagNames = await query;
-
-  return enabledFlagNames.map(
+  const enabledFlagNames = (await query).map(
     (row: { name: string }) => row.name as FeatureFlagName,
   );
+
+  // Force feature flags for E2E tests via URL query params
+  if (process.env.E2E_TEST_ENV === "local") {
+    const forcedFeatureFlags = headers().get("x-forced-feature-flags");
+    if (forcedFeatureFlags) {
+      const forcedFeatureFlagsFiltered = forcedFeatureFlags
+        .split(",")
+        .filter((forcedFeatureFlag) =>
+          featureFlagNames.includes(forcedFeatureFlag as FeatureFlagName),
+        );
+      return [
+        ...new Set([...enabledFlagNames, ...forcedFeatureFlagsFiltered]),
+      ] as FeatureFlagName[];
+    }
+  }
+
+  return enabledFlagNames;
 }
 
 /**
diff --git a/src/e2e/pages/authPage.ts b/src/e2e/pages/authPage.ts
index 4831b776dd..b61e27a4aa 100644
--- a/src/e2e/pages/authPage.ts
+++ b/src/e2e/pages/authPage.ts
@@ -71,4 +71,37 @@ export class AuthPage {
     expect(verificationCode).toBeDefined();
     await this.enterVerificationCode(verificationCode as string);
   }
+
+  async signInToFxA(email: string, password: string) {
+    await this.page.goto(process.env.FXA_SETTINGS_URL as string);
+    await this.page.context().clearCookies();
+    await this.page
+      .locator("//input[@type='password'] | //div/input[@type='email']")
+      .waitFor({ state: "visible" });
+    const visible = await this.useDifferentEmailButton.isVisible();
+    if (visible) {
+      await this.useDifferentEmailButton.click();
+      await this.page.waitForURL(/^(?!.*signin).*/);
+    }
+
+    // enter email
+    await this.emailInputField.fill(email);
+    await this.continueButton.click();
+    await this.page.waitForURL(/^(?!.*signin).*/);
+
+    // enter password
+    await this.passwordInputField.fill(password);
+    await this.continue({ waitForURL: process.env.FXA_SETTINGS_URL });
+  }
+
+  async initSilentAuth() {
+    await this.page.setExtraHTTPHeaders({
+      "x-forced-feature-flags": "PromptNoneAuthFlow",
+    });
+    await this.page.goto(
+      `${process.env.E2E_TEST_BASE_URL as string}/?utm_source=moz-account&utm_campaign=settings-promo&utm_content=monitor-free`,
+    );
+    // FxA can take a while to load on stage:
+    await this.page.waitForURL("**/authorization?**");
+  }
 }
diff --git a/src/e2e/specs/auth.spec.ts b/src/e2e/specs/auth.spec.ts
index deeb03664b..9dae4de91f 100644
--- a/src/e2e/specs/auth.spec.ts
+++ b/src/e2e/specs/auth.spec.ts
@@ -45,7 +45,7 @@ test.describe(`${process.env.E2E_TEST_ENV} - Authentication flow verification @s
     landingPage,
     dashboardPage,
   }, testInfo) => {
-    // speed up test by ignore non necessary requests
+    // speed up test by ignoring non-necessary requests
     await page.route(/(analytics)/, async (route) => {
       await route.abort();
     });
@@ -68,4 +68,62 @@ test.describe(`${process.env.E2E_TEST_ENV} - Authentication flow verification @s
       },
     );
   });
+
+  test("Verify successful silent authentication with existing user", async ({
+    page,
+    authPage,
+  }, testInfo) => {
+    // speed up test by ignoring non-necessary requests
+    await page.route(/(analytics)/, async (route) => {
+      await route.abort();
+    });
+
+    // login to FxA
+    await authPage.signInToFxA(
+      process.env.E2E_TEST_ACCOUNT_EMAIL as string,
+      process.env.E2E_TEST_ACCOUNT_PASSWORD as string,
+    );
+
+    // start authentication flow
+    await authPage.initSilentAuth();
+
+    // assert successful login
+    await page.waitForURL("**/user/dashboard/**");
+
+    await testInfo.attach(
+      `${process.env.E2E_TEST_ENV}-silent-authentication-monitor-dashboard.png`,
+      {
+        body: await page.screenshot(),
+        contentType: "image/png",
+      },
+    );
+  });
+
+  test("Verify failed silent authentication with existing user", async ({
+    page,
+    authPage,
+    landingPage,
+  }, testInfo) => {
+    // speed up test by ignoring non-necessary requests
+    await page.route(/(analytics)/, async (route) => {
+      await route.abort();
+    });
+
+    // start authentication flow
+    await authPage.initSilentAuth();
+
+    // assert failed login
+    await expect(landingPage.monitorLandingHeader).toBeVisible({
+      // The header can take a while to show in Playwright.
+      timeout: 5000,
+    });
+
+    await testInfo.attach(
+      `${process.env.E2E_TEST_ENV}-silent-authentication-monitor-dashboard.png`,
+      {
+        body: await page.screenshot(),
+        contentType: "image/png",
+      },
+    );
+  });
 });
diff --git a/src/middleware.ts b/src/middleware.ts
index 81771ac3f9..4a805f5277 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -12,6 +12,7 @@ export function middleware(request: NextRequest) {
 
   const requestHeaders = new Headers(request.headers);
   requestHeaders.set("x-nonce", nonce);
+
   // Add the CSP to the request headers - that will make Next.js detect it and
   // add it to the inline `<script>` tags that it injects itself, as per
   // https://github.com/vercel/next.js/discussions/51039#discussioncomment-6596642