Use double opt-in for your newsletter

What it means

With single opt-in, anyone who types an address in your sign-up form is added to your list immediately. With double opt-in, the address is added only after its owner clicks a link in a confirmation email.

It is one extra click for the subscriber, and a big gain for you.

Why it matters

• No typos: an address like jon@gmial.com never confirms, so it never bounces later.
• No fake sign-ups: bots and pranksters who fill your form with other people's addresses are filtered out.
• No spam traps: abandoned or trap addresses cannot click, so they never reach your list. One trap hit can get you blacklisted.
• Fewer complaints: people who confirmed remember signing up and are less likely to click "Report spam".
• Proof of consent: you keep the date and time of the confirmation, which helps with privacy laws such as the GDPR.

Gmail, Yahoo and Outlook judge you on bounces and complaints. A clean list is the base of a good sender reputation.

How to set it up

1. Turn it on in your newsletter tool. Most tools (Mailchimp, Brevo, MailerLite and others) have a "double opt-in" or "confirmation email" setting for each list or form.
2. Write a short confirmation email. A clear subject such as "Please confirm your subscription", one sentence explaining why, and one big button.
3. Send it immediately. People confirm when the sign-up is still fresh in their mind. Send it from your real domain, with SPF, DKIM and DMARC in place.
4. Add a thank-you page after the form that says "Check your inbox to confirm", and mention the spam folder.
5. Protect the form with a captcha or a hidden field, so bots do not trigger thousands of confirmation emails.
6. Clean unconfirmed addresses. If someone has not confirmed after a few days, you may send one reminder, then delete the address.

Your website's own forms

If your sign-up form is custom code, it must store the address as "pending", send a unique link, and mark the address as "confirmed" only when that link is clicked. Never send newsletters to pending addresses.

What about your existing list?

• Old addresses that never confirmed are the riskiest. Remove addresses that bounce or have not opened anything for a long time.
• Never buy or rent a list: it is full of traps and people who never asked for your emails.

Check that it is fixed

Sign up to your own form with the unique test address from the Delivmail home page. The confirmation email arrives there and you get a full report: authentication, blacklists and spam score. Fix anything red, because a confirmation email in spam means lost subscribers. Then click the link and check that the address only appears in your list once confirmed.