Opt-in: definition and how it works
Published and updated
Opt-in is the recipient's recorded agreement to receive text messages from you, collected before the first message and kept as proof, with a higher written standard for marketing.
How it works
Consent is the foundation of every SMS rule set. The United States regulation requires prior express consent for automated texts and written consent for marketing; the CTIA messaging principles expect any business sender to hold consent and to let recipients withdraw it; Indian rules run promotional traffic through registered preferences; European data protection law requires a lawful basis, which for marketing is consent. The details differ, the shape does not: get agreement first, keep evidence, make leaving easy.
Single opt-in records consent at the point of collection, such as a checked box next to a phone field or a keyword texted to your number. Double opt-in adds a confirmation message that the person must answer before anything else is sent. Double opt-in costs one message and some conversion, and buys certainty that the number is real, is the person's, and was not typed in by someone else.
Record what you would need to show later: the number, the timestamp, the wording the person saw, and where they saw it. Consent given for account notifications does not cover marketing, so track the purpose too.
Transactional messages the person triggered, such as a passcode they requested or a receipt for an order they placed, sit on firmer ground than marketing everywhere, but they still need the number to have been given for that purpose.
- The CTIA Messaging Principles and Best Practices expect Non-Consumer senders to hold consent, hold express written consent for marketing, and let recipients revoke it. api.ctia.org, checked on September 4, 2026
How this applies with textbee
textbee sends what you tell it to, so consent is your record to keep. A practical pattern is to let people opt in by texting a keyword to your number and to store the inbound message as the proof, since replies land in your account as received messages.
Related terms
- TCPA: The TCPA (Telephone Consumer Protection Act) is the United States law, implemented by the FCC in 47 CFR 64.1200, that requires prior express consent before automated calls or texts and written consent before marketing ones.
- STOP keyword: STOP is the conventional reply a recipient sends to opt out of a sender's text messages, which the sender must recognise and honour by ending the messages and confirming once.
- A2P and P2P messaging: P2P is a text one person sends to another; A2P is a text an application sends to a person, and carriers apply different rules, filters and prices to each.
- DND registry: A DND (Do Not Disturb) registry is a national list of phone numbers whose owners have opted out of promotional calls and texts, which senders and operators must check before sending marketing.
Sources
- Opt-in, api.ctia.org, checked on September 4, 2026