diff --git a/backend/__tests__/unit/services/emailService.test.js b/backend/__tests__/unit/services/emailService.test.js
index baef2c659f..107339b038 100644
--- a/backend/__tests__/unit/services/emailService.test.js
+++ b/backend/__tests__/unit/services/emailService.test.js
@@ -22,6 +22,35 @@ describe('emailService', () => {
     process.env = originalEnv;
   });
 
+  // Every QA walk registers an @ops.commonly.invalid account, and its
+  // verification email bounced against the sender's reputation.
+  it('skips a reserved-domain recipient without throwing, sends nothing, and logs without the address', async () => {
+    process.env.SMTP2GO_API_KEY = 'smtp-key';
+    const infoSpy = jest.spyOn(console, 'info').mockImplementation(() => {});
+
+    const result = await sendEmail({
+      to: 'walk-123@ops.commonly.invalid',
+      subject: 'Verify Your Email - Commonly',
+      textBody: 'Plain text',
+      htmlBody: '<p>Plain text</p>',
+    });
+
+    expect(result).toEqual({ skipped: 'reserved_domain', data: { skipped: 'reserved_domain' } });
+    expect(axios.post).not.toHaveBeenCalled();
+    expect(infoSpy).toHaveBeenCalledTimes(1);
+    expect(JSON.stringify(infoSpy.mock.calls[0])).not.toContain('commonly.invalid');
+    infoSpy.mockRestore();
+  });
+
+  it('skips a reserved-domain recipient even when email is not configured: it could never deliver', async () => {
+    const infoSpy = jest.spyOn(console, 'info').mockImplementation(() => {});
+    await expect(sendEmail({
+      to: 'a@x.test', subject: 'Hello', textBody: 'Plain text', htmlBody: '<p>Plain text</p>',
+    })).resolves.toEqual(expect.objectContaining({ skipped: 'reserved_domain' }));
+    expect(axios.post).not.toHaveBeenCalled();
+    infoSpy.mockRestore();
+  });
+
   it('throws a typed error without an SMTP2GO API key and makes no network call', async () => {
     await expect(sendEmail({
       to: 'person@example.com',
diff --git a/backend/services/emailService.ts b/backend/services/emailService.ts
index 23e7a7b82f..696e15431d 100644
--- a/backend/services/emailService.ts
+++ b/backend/services/emailService.ts
@@ -1,3 +1,4 @@
+import { isReservedEmailDomain } from '../utils/reservedEmailDomain';
 // eslint-disable-next-line global-require
 const axios = require('axios');
 
@@ -24,6 +25,19 @@ export const sendEmail = async ({
   textBody,
   htmlBody,
 }: SendEmailOptions): Promise<any> => {
+  // The backstop for every caller (sprint-review on #2298): an address on a
+  // reserved domain (.invalid, .test, .example, .localhost) can never receive
+  // mail, so a send buys only a bounce against the reputation every real
+  // person's email depends on. Every QA walk registers such an account and its
+  // verification email bounced. Returned, never thrown: a throw would send the
+  // background verification into its retry and log as a delivery failure.
+  // `data` mirrors the reason for callers that log the provider's response.
+  // Callers that can skip earlier still should (the digest skips before it
+  // mints a token); this only stops the send itself.
+  if (isReservedEmailDomain(to)) {
+    console.info('Email skipped: the recipient is on a reserved domain and cannot be delivered.', { subject });
+    return { skipped: 'reserved_domain', data: { skipped: 'reserved_domain' } };
+  }
   const apiKey = process.env.SMTP2GO_API_KEY;
   if (!apiKey) throw new EmailNotConfiguredError();