Key takeaways
- Single opt-in grows lists faster; double opt-in usually produces cleaner lists.
- Some jurisdictions and situations favour confirmed consent.
- You can use different approaches for different sources.
Definitions
- Single opt-in: people are subscribed as soon as they submit the form.
- Double opt-in: people must click a confirmation link in an email before being subscribed.
Trade-offs
- Single: more subscribers, but more typos, fake addresses and low-intent sign-ups.
- Double: fewer subscribers, but confirmed addresses and a clear consent record.
A practical approach
Many businesses use double opt-in for cold or high-risk sources (e.g. giveaways, open forms targeted by bots) and single opt-in for warm sources such as purchases where consent is clearly given. Check the consent requirements that apply where your subscribers are.
FAQ
Does double opt-in improve deliverability?
It generally helps list quality - fewer invalid addresses and spam traps - which supports good deliverability over time.