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Email verification

Use verification to reduce bounces, protect sender reputation, and clean recipient lists before high-volume sends.

What verification helps with​

  • Remove obvious invalid recipients before send.
  • Reduce hard bounces and complaint risk.
  • Keep suppression and list hygiene workflows accurate.
  • Improve signal quality for campaign and transactional delivery monitoring.

Verify during send (fastest path)​

For most transactional flows, enable verification as part of send so invalid recipients are filtered before delivery attempts:

// the `validateEmailAddresses` option will verify then filter and remove bad recipients
// you can also configure the method to throw instead with `VALIDATE_ERROR_IF_INVALID`
await mailslurp.sendEmail(inboxId, {
  to: [recipient, bouncedRecipient],
  validateEmailAddresses:
    SendEmailOptionsValidateEmailAddressesEnum.VALIDATE_FILTER_REMOVE_INVALID,
});

This approach keeps application logic simple and lowers bounce risk without extra pre-processing jobs.

Verify during list intake and cleanup​

For marketing lists or imported contacts, verify addresses when collected or before batch sends:

const mailslurp = new MailSlurp(config);
const res =
  await mailslurp.emailVerificationController.validateEmailAddressList({
    validateEmailAddressListOptions: {
      emailAddressList: ['contact@mailslurp.dev', 'bad@mailslurp.dev'],
    },
  });
expect(res.resultMapEmailAddressIsValid['contact@mailslurp.dev']).toEqual(
  true
);
expect(res.resultMapEmailAddressIsValid['bad@mailslurp.dev']).toEqual(
  false
);

Use this mode when you need explicit validation outcomes for reporting, suppression, or manual review.

  1. Verify at collection/import time for large lists.
  2. Verify again during send for critical transactional workflows.
  3. Store invalid/bounced outcomes in suppression tables.
  4. Re-check long-lived contacts before major campaigns.

Common mistakes to avoid​

  • Treating verification as a permanent guarantee.
  • Skipping suppression updates after bounce events.
  • Verifying only once and never re-checking stale lists.