# Single opt-in

Single opt-in is a signup flow in which a person joins the list the moment they submit the form, with no confirmation email to click. It gets the most signups through, but lets fake, mistyped and disposable addresses onto the list.

Canonical page: https://getlaunchlist.com/glossary/single-opt-in. Updated 2026-10-15.

## How single opt-in works

The form submission is the only step. The visitor fills in the form, sees the thank-you screen, and is on your list. There is no email to open and no link to click, so nobody drops off between signing up and confirming.

## When it is the right call

Single opt-in is a reasonable choice in a few situations:

- **There is no email to confirm.** A signup identified by a phone number or a username can't click an email link.
- **You are testing demand, not building a mailing list.** If you only want to know whether people raise their hand, every signup counting at once is the point.
- **Speed matters more than proof.** On a form where people sign up in person, such as at an event, a confirmation email can feel like an extra hurdle.

For a list you plan to email at launch, the stronger default is [double opt-in](https://getlaunchlist.com/glossary/double-opt-in), where the comparison of the two is set out side by side.

## The risks

Without a confirmation step, three kinds of address get onto the list: typos (gmial.com instead of gmail.com), throwaway inboxes from [disposable email](https://getlaunchlist.com/glossary/disposable-email) services, and addresses typed by bots. None of them will ever read your launch email, and sending to them bounces or lands in spam traps, which hurts your [email deliverability](https://getlaunchlist.com/glossary/email-deliverability). On a referral waitlist there is a fourth risk: if referrals count at signup, made-up addresses can be used to climb the line.

## Making single opt-in safer

- Run bot checks on every signup, such as a hidden honeypot field and a minimum time to fill in the form.
- Recognize known throwaway email domains.
- Suggest a fix for common typos before the form is sent.
- Check addresses before your first big send, and leave out the ones that bounce.

## Single opt-in in LaunchList

Waitlist [forms](https://getlaunchlist.com/features/forms) ask people to confirm their email by default, and you can switch confirmation off on any form. With it off, a signup is subscribed the moment the form is sent, and a referral counts at signup instead of at confirmation. The same applies to people who sign up with a phone number or a username.

The [spam checks](https://getlaunchlist.com/features/contact-trust) run either way: rate limits, a hidden field only bots fill in, a check for forms sent too fast, and recognition of throwaway email domains. The email field also offers a fix for common typos, so gmial.com becomes gmail.com with one tap.

## Frequently asked questions

### Does single opt-in hurt deliverability?

It can. Without a confirmation step, addresses that don't exist or belong to nobody get onto the list, and they bounce or land in spam traps when you send. Mailbox providers count that against you, so the risk grows the more you mail an unconfirmed list.

### When is single opt-in the right choice?

When the signup has no email to confirm, such as a phone number or a username, when you are running a short demand test you don't plan to email, or when you have strong spam checks in front of the form and want every signup counted at once.

### Is single opt-in legal?

In many places, yes, as long as people clearly agreed to hear from you. Some countries expect proof of consent that a confirmation click provides more easily, so check the rules where your audience lives before you rely on it.

## Related terms

- [Double opt-in](https://getlaunchlist.com/glossary/double-opt-in.md)
- [Disposable email](https://getlaunchlist.com/glossary/disposable-email.md)
- [Email deliverability](https://getlaunchlist.com/glossary/email-deliverability.md)