Legal basis for sending messages

Which legal basis do I need for sending SMS, WhatsApp, RCS and voice messages?

As a rule, you may only send marketing messages to recipients who have given their prior express consent. This applies regardless of the channel - to SMS as well as to WhatsApp, RCS and marketing voice calls. In Germany, this follows in particular from Section 7 of the Act Against Unfair Competition (UWG); comparable rules apply in most other countries.

We recommend obtaining consent via double opt-in: the recipient first actively signs up, for example via a form on your website (opt-in). Only then do you send them a message asking to confirm that sign-up. If the recipient does not confirm, do not send them any further messages. Without a prior opt-in you must not send the confirmation message either - for WhatsApp and RCS, Meta and Google explicitly require this. Document consent in a way that allows you to prove it in case of a dispute (time, wording, origin).

Transactional Messages

Transactional messages without advertising - such as one-time passwords (OTP), appointment reminders or shipping confirmations - do not require marketing consent. However, you still need a legal basis under the GDPR, usually the performance of a contract. Do not mix advertising into transactional messages, otherwise the stricter rules for marketing apply.

Opt-Out

Give recipients a simple way to opt out in every marketing message, for example by replying STOP or via an unsubscribe link. You must honor incoming opt-outs without delay.

Channel-Specific Requirements

  • SMS: Under narrow conditions, Section 7 (3) UWG allows marketing to existing customers without express consent in Germany. Only rely on this after legal review.
  • WhatsApp: Meta strictly requires an opt-in from the recipient for business messages and compliance with the Business Messaging Policy. Outside the 24-hour customer service window, only approved message templates may be sent.
  • RCS: Opt-in is mandatory here as well; Google and the carriers review agents and their use cases during launch. An opt-out option (e.g. STOP) is required.
  • Voice: Marketing calls are subject to the strictest requirements - in Germany, calls to consumers are only permitted with prior express consent.

Data Protection

When sending via seven, you process personal data. Make sure to sign our Data Processing Agreement and include the messaging provider in your privacy policy.

Further Reading

You can read more details about the legal basis and double opt-in in our blog post.

This article does not replace individual legal advice.

Last updated: August 13, 2026

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