"Opt-in" refers to a person actively and explicitly agreeing to receive marketing communications or have their data used in a specific way, before it happens. "Opt-out" refers to a system where a person is included by default and must actively choose to be excluded.
Why it matters
Which model applies — opt-in or opt-out — is often determined by law, not just preference (for example, many jurisdictions require opt-in consent for email marketing and certain types of tracking), and getting this wrong is a common source of compliance violations, not just a poor user experience.
In a sentence
"Because we operate in markets that require opt-in consent, new signups don't get added to marketing emails automatically — they have to actively check the box."
Related terms
- Antonyms: Opt-in and opt-out are direct antonyms of each other.