List management
Updated
Double opt-in
Definition
Double opt-in (confirmed opt-in) is a signup process where a new subscriber must click a link in a confirmation email before they are added to the list. The signup is the first opt-in, the click is the second.
How it works
Someone submits a form. Instead of subscribing them immediately, the list stores them as pending and sends a confirmation email with a unique link.
When they click, the status becomes subscribed and the list records when (and often from which IP) consent was confirmed. If they never click, they never receive marketing email.
Single opt-in skips the confirmation step and subscribes on form submission.
Example
This is Lumail's native double opt-in flow.
Why it matters
It keeps typos, fake addresses and bot signups off the list, which keeps bounce and complaint rates low and protects you from spam traps.
It produces evidence of consent. GDPR does not mandate double opt-in by name, but it requires you to be able to demonstrate consent, and confirmed opt-in is the strongest record. In some markets, such as Germany, it is the expected practice.
Best practices
- Send the confirmation email immediately, with a clear subject such as Confirm your subscription.
- Keep the confirmation email short with one obvious button.
- Tell people on the thank-you page to check their inbox.
- Expect some signups never to confirm. The ones who do are more engaged, and list quality matters more than raw size.
How Lumail handles double opt-in
Lumail has native double opt-in. With it enabled, new subscribers from forms, the API, capture pages and integrations are created as pending, receive your confirmation email (the link is valid for 24 hours) and only become subscribed after the click.
Lumail stores confirmedAt and confirmationIp, writes a timeline event, then starts tag-triggered workflows. Pending subscribers never receive campaigns.
Check a real message with the free mail tester or the spam tester.
Frequently asked questions
Is double opt-in required by GDPR?
Not explicitly. GDPR requires consent you can demonstrate, and double opt-in is the most robust way to prove it. Some EU markets treat it as the expected standard.
Does double opt-in reduce list growth?
It reduces the raw count, because some people never confirm. Those unconfirmed addresses are often typos or low-intent signups that would have hurt deliverability anyway.
Single vs double opt-in: which should I use?
Use double opt-in for public forms, paid traffic and markets that expect consent evidence. Single opt-in can work for low-risk sources like account signups in your own product.
Related terms, tools and docs
- List managementList hygieneList hygiene is the routine of removing or suppressing email addresses that hurt deliverability: hard bounces, spam complainers, long-inactive subscribers, invalid addresses and likely spam traps..
- MetricsBounce rateEmail bounce rate is the percentage of sent emails that the receiving server rejected as undeliverable.
- MetricsSpam complaint rateSpam complaint rate is the percentage of delivered emails that recipients reported as spam.
- List managementOne-click unsubscribeOne-click unsubscribe is a standard (RFC 8058) that lets mail clients unsubscribe a recipient with a single HTTPS POST, without opening a web page.
- Free toolFree mail testerSend a real email and get an SPF, DKIM, DMARC and content report.
- DocsEnable double opt-inNative confirmation before anyone gets campaigns.
- DocsAutomatic list cleanupUnsubscribe people inactive for 30, 90 or 180 days.
- DocsEmail verification APICheck an address before you add it.
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