Double opt-in – why and when? [1/2]

It is generally a good idea to grow your list using double opt-in. As a little refresher -

What is double opt-in?

  • Double opt-in means your users have to confirm their wish to sign up a 2nd to active their subscription – e.g. by clicking a link in a checkmail (typical), or by answering to that checkmail, or by entering a code sent via checkmail (see screenshots below).
  • The idea of the second step is to make sure, only the actual holder of the email address can subscribe and no unauthorized third party.
  • By the way, sometimes double opt-in is also referred to as closed loop opt-in (in case you search for more information).

Uncommon: Double opt-in verification by entering a code on a website

Error-prone: Double opt-in by answering to a checkmail

Main-advantages of using double opt-in:

  1. Law:
    In some countries, like Germany, a double opt-in is the only accepted legal proof of consent.
  2. Deliverability:
    1. Non-existing addresses are filtered out immediately; thus, they can’t hurt the sender’s reputation among email providers.
    2. Seeded spamtraps (e.g. typo-domains like can’t poison your list; this also protects your reputation and prevents unnecessary blacklistings.
  3. Stronger permission:
    The two-step verification results in a double informed consent. Such clear communication and deliberate action is worth more than a brief click. It forms a stronger initial relationship – no need for “permission reminders” or anything like that. Also it shows you care about the spam problem. In the end, emails are less likely to be classified/marked as spam.
  4. Cleaner web:
    If you (1) send neutral checkmails focusing solely on the consent without further promoting your business, and if you (2) apply the UBC-definition of spam, the spam outcome will be reduced. (In case of a mistake, people will just have to accept one unsolicited non-commercial email.)
  5. Better response rates:
    The gain in data quality manifests itself in a significantly higher response. MailChimp took a closer look at a sample recently. They found +75.6% in total opens, +114% in clicks, -48.3% in hard- and -25% in soft-bounces for double opt-in lists compared to single opt-in lists. That’s huge!

Potential draw-backs with double opt-in:

  1. Friction loss:
    Due to several reasons, not every new subscriber confirms his subscription; depending on how well the process has been implemented, the sender gains 10%-50% less opt-ins compared to single/confirmed opt-in.
  2. Pseudo-Security:
    Double Opt-in gives a false sense of security. Even this isn’t 100% false-proof. Think e.g. of spamfilters or other crawlers that may follow links within incoming unknown emails. This way the activation-link could be triggered without any contribution of the address holder. A potential danger which is not just theoretical as you can read on or on
  3. Administrative costs:
    1. one additional email (“checkmail”),
    2. one additional landing page to catch to click,
    3. an extended data scheme (e.g. double opt-in timestamp)

My advice:

  • Use confirmed opt-in where possible, double opt-in where necessary. The more the danger of entering fake email addresses or typing errors, the greater the necessity for double opt-in. Broadly speaking, it makes a difference whether you collect an email address in a purchase order form or in a prize draw.
  • Continuously optimize your double opt-in process and strive for a double opt-in rate of 90% or more – i.e. a state where 9 out of 10 sign-ups also click the confirmation link. We will look at how to do that in a follow-up posting.


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4 Responses to Double opt-in – why and when? [1/2]

  1. Pingback: Double-Opt-in: Vor- und Nachteile im Überblick - dialogue1 E-Mail-Marketing Blog Tipps, Ideen und Fallbeispiele

  2. Pingback: Double opt-in – 12 setup-tips to get a maximum outcome [2/2] | E-Mail Marketing Tipps

  3. Why & when to use double opt-in for list building:

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