Before we start to explore the detail of single opt-in and double opt-in here’s a quick explanation of what both terms mean…
What is single opt-in?
People fill out a form on your website to include their email address and when they hit the submit button are added to any relevant / selected marketing lists.
The email address is added every time without knowing whether it is actually a valid email address.
What is double opt-in?
Same thing here except that when the submit button is pressed an email is sent to that person using the email address they entered and they have to click a secure link in order to authorise the next steps in the sign-up process.
Their email address doesn’t get added until the authorisation link is clicked.
Which is the better method?
There’s pros and cons of both ways but if you’re looking for the highest quality list then double opt-in is the way to go.
Using double opt-in you’ll always know that every single person on your marketing list is meant to be there and has confirmed the existence of their email address by clicking on the link you sent when they signed up.
That said, single opt-in works perfectly well when there’s tight form validation for email address entry to stop incorrect and fake data getting through.
Is double opt-in required by law?
Currently, it’s not and there’s nothing wrong with using single opt-in providing you stick to general best practice for data capture and obtaining consent.
The important thing to focus on is to ensure that any sign-up processes provide clear and concise choices, making it easy for people to understand what they are consenting to and how their data will be stored and used.
Pros and cons of using single opt-in
The good stuff…
- Quicker sign-up process
- Faster list growth
What you might not like…
- Incorrect email addresses (spelling mistakes)
- Fake email addresses (from spambots)
- Sender reputation damage
- More complaints
- Lower response rates
Pros and cons of using double opt-in
More benefits than single opt-in…
- Assurance of valid email addresses
- Confirmation of consent to receive emails
- Protection against spambots, email scams and fake subscribers
- Reduced complaint rates
- Higher open and click rates
- Lower bounced email rates
Lists will grow more slowly…
- More steps involved
- Slower list growth / lost email addresses
Which method should you use?
That’s really down to which matches your requirements but our advice would be to stick to data capture best practice principles and to seek advice from the ICO or the DMA if you are unsure.
Opinions vary on which method is best and the answer is not always straightforward. For example, Mailchimp recently made single opt-in the default setting for everyone outside of the EU but stuck to double opt-in for those within the EU.
GDPR has refocused every business on to managing data in a much better way and we’re fully supportive of what it represents.