Single Opt-In


The term “single opt-in” refers to a registration procedure in email and permission marketing, in which the entry of an email address applies as confirmation for the reception of newsletters, advertising emails or mailings. If an interested party submits an email address on a website form, this entry is considered to be a permission by the advertiser. The advertiser can then send emails, newsletters or mailings to the prospective customer without having to confirm the permission again or receiving a separate confirmation email as is the case with the double opt-in and the confirmed opt-in. A singing opt-in is provided by law as a minimum requirement for the receipt of email advertising, but its specific implementation is not defined. The latter often leads to ambiguities in advertising companies, as opt-ins generally have to fulfill certain conditions and have to be documented.

General information

The single-opt-in procedure has long been a common practice in various marketing disciplines. However, because a simple opt-in can lead to abuse, the procedure has often been criticized. If a stranger inputs an email address of another person in a web form, this person will then receive advertisement without explicitly making a decision to do so. The sender must be able to demonstrate that the registered email address is also the person who owns this email address. For this reason, the confirmed opt-in and the double opt-in procedures were introduced.

How it works

A single opt-in can run as follows:

  • A user enters his / her e-mail address, telephone number or other contact possibility into a web form or a distribution list. The user may also agree to receive newsletters by telephone or fax, by providing their contact information.
  • On the sender side, the contact option is entered into a database and saved. Sometimes the user is presented with a website that confirms his entry into the database.
  • The sender can now use this data record (lead) to send the recipient a commercial e-mail or regular newsletter within the scope of their email distribution list. This distribution is usually automated with the IT infrastructure of the consignor or with a third-party provider who specializes in email marketing.
  • The recipient receives a commercial email or several newsletters, which are spread over specific time periods. In addition to the advertising content, these usually contain the provider’s imprint on and an opt-out, so that the recipient of the email can choose to no longer receive such messages in the future.

The problem with each single opt-in is that the entry of an email address can also be done by third parties or bots. In these cases, the person whose email address has been registered does not correspond to the person or the bot who entered the email address. This may result in legal consequences. First and foremost, this concerns the consent of the addressee. They must agree to receiving the newsletters or emails. Furthermore, email marketing may not constitute unreasonable harassment if it is to be permitted. The applicable law can be found in the German Tele-Media Act.

Moreover, the sender cannot be sure that it is a correct and valid email address. Under certain circumstances, the newsletter may not arrive at the recipient and must be counted as a advertisement loss. The single opt-in procedure, therefore, cannot ensure that high-quality datasets with correct data gets generated. From the viewpoint of lead generation, follow-up is missing, which confirms the correctness of the data.

Legal aspects of the single opt-in

At the very least, advertisers can use the single opt-in procedure when the process meets certain legal conditions, is documented by the advertiser, and the advertiser can provide a log with the key data of the actual registration. It is important that the single opt-in is supplemented by a confirmation email or a confirmation in a different form, otherwise the existence of a consent cannot be proven. Any warnings can be avoided in this way. The quality of the datasets is also increased as they are real persons who have expressed their interest in the newsletter through an opt-in. Consent to the receipt of a newsletter must not only be given and confirmed, the sender must also be able to prove that consent has been given. This means that he will have to store different data:

  • The source, IP address, and host with which the single opt-in was performed should be saved. In addition, each opt-in receives a time stamp to be able to understand when the opt-in took place.
  • This data should be encrypted before the sender stores it in his / her database.
  • A subsequent modification of this data should not be possible by the system to prevent tampering.
  • The data should be kept for at least a few years in order to adequately react to a later warning.

Moreover, the web form or website used to collect email addresses must meet various conditions:

  • An opt-in may not be a part of the GTC (the coupling prohibition).
  • If the opt-in is carried out by means of a check mark or checkbox, these must not be crossed or required as mandatory fields. All other information should be expressly stated to be voluntary.
  • Each opt-in must inform about the specific content of the newsletter and the frequency of distribution.
  • When registering, the customer must be informed of how to cancel the newsletter. In addition, every newsletter should include a simple log-off option.
  • Data protection is not legally binding on the site of the opt-in. However, it is useful to inform the customer about the use of the data.

Relevance to online marketing

A single opt-in can lead to warnings under certain conditions. For this reason, it is advisable to add a confirmation email (confirmed opt-in) to the single opt-in or a double opt-in - which is the established practice regardless. The opt-in function is one of the most important components of email marketing. However, some pitfalls, however, make correct implementation relatively difficult. Email marketing is considered to be one of the simplest and most effective advertising measures, but the various legal aspects should not be ignored.