Sales Loves MarketingAn opt-in is someone's active permission to receive your marketing messages. They give it by ticking an unticked box or submitting a sign-up form, and it tells you they expect to hear from you. The opposite is an opt-out, where someone asks to stop receiving messages.
Why does opt-in matter?
Opt-in protects two things:
- Legal standing. In the EU, email marketing to individuals generally needs prior consent. Even where it doesn't, consent is the safest basis.
- Deliverability. Mailbox providers track spam complaints. Gmail asks bulk senders to keep their spam rate below 0.3 percent and ideally below 0.1 percent. Emailing only people who asked to hear from you is the most direct way to keep complaints low and protect your deliverability.
Gmail's sender guidelines are explicit: make sure recipients opt in, confirm each address before subscribing it, and don't email people who didn't sign up.
What is the difference between single and double opt-in?
| Single opt-in | Double opt-in | |
|---|---|---|
| Steps | Submit the form | Submit the form, then click a link in a confirmation email |
| Speed | Added immediately | Added after confirmation |
| List quality | Typos and fake addresses get in | Only working, confirmed addresses |
| Proof of consent | Form record | Form record plus confirmation click |
Double opt-in loses some sign-ups who never click the link. In return you get a cleaner list and better evidence of consent, which matters if anyone challenges it later.
What does the law say about opt-in?
- United States. The CAN-SPAM Act does not require opt-in. Every commercial email must include a working way to opt out, which must keep working for at least 30 days after sending, and opt-outs must be honoured within 10 business days. The FTC notes the law makes no exception for business-to-business email.
- European Union. The ePrivacy Directive allows unsolicited marketing email only with the recipient's prior agreement. The main exception covers existing customers: if you got their address during a sale, you may market similar products as long as they could refuse at that point and in every message. Where you rely on consent, the GDPR says it must be as easy to withdraw as to give.
- Other countries have their own rules, and some treat emails to company addresses differently from emails to individuals. Check the rules where your recipients are.
How do you collect opt-ins well?
- Leave consent boxes unticked. Gmail's guidelines warn against pre-checked opt-in boxes.
- Say what people will get and how often, next to the form.
- Ask for marketing consent separately from downloading a lead magnet, rather than making it a condition.
- Record when, where and how each person opted in.
- Let people choose topics, which also helps with list segmentation.
- Make opting out easy. Large senders to Gmail must support one-click unsubscribe.
Related terms
Frequently asked questions
What is the difference between single and double opt-in?
With single opt-in, someone is added to your list as soon as they submit the form. With double opt-in, they first get a confirmation email and are only added after they click the link. Double opt-in proves the address is real and that its owner signed up.
Does the CAN-SPAM Act require opt-in?
No. CAN-SPAM is an opt-out law. It does not require prior consent, but every commercial email must offer a way to opt out, and opt-outs must be honoured within 10 business days. It applies to business-to-business email too.
Is opt-in required in Europe?
For email marketing to individuals, generally yes. The EU ePrivacy Directive only allows unsolicited marketing email with the recipient's prior agreement, with an exception for existing customers buying similar products who were given a chance to refuse. Rules for emails to company addresses vary by country.