Cross-checking recipients

  • Updated

Optimizely Campaign identifies the recipients of a mailing and which internal lists are used for this purpose. If you maintain recipient lists outside the Optimizely Campaign environment, this information can help keep your lists consistent. If you have questions regarding the operation and configuration of your client, contact customer support.

Optimizely Campaign validates recipient data in the following modules and functions:

  • Importing recipient lists
  • Calculating recipients for a mailing
  • Sending out a mailing
  • Editing the blocklist

The following lists, managed internally by Optimizely Campaign, also impact the validation of recipients for mailing dispatches:

  • Unsubscribe list
  • Bounce counter

Cross-checking recipient lists


When you import a recipient list, Optimizely Campaign filters out duplicates. Duplicates within imported CSV files are also checked, so only one record per recipient is imported.

If you select the Clear recipient list before importing option, the list is not cross-checked because it is deleted before any data is imported.

If you select the Import new recipients and update existing records option, existing records are not treated as duplicates but are overwritten with new values.


Imported records are cross-checked against the blocklist. Blocked recipients, including those serving as placeholders, are not imported.


Unsubscribers are included on an unsubscribe list, which usually applies to clients (though not inherited). You can create unsubscribe lists based on recipient lists and permanently linked to a recipient list, which do not affect other recipient lists in the same client.

Unsubscribers are not deleted from the database and not imported a second time.

Incorrect data records

During import, Optimizely Campaign checks the following email address criteria:

  • An address must contain exactly one @ symbol.
  • An address's local element (before @) may not begin or end with a dot.
  • Two consecutive dots cannot occur
  • Blank spaces and the following special characters are not permitted: ( ) [ ] \ ; : , < >
  • An address's domain element (after @) must conform to the domain name system rules

Imported records must also have fields in the recipient list that match columns in the imported list. Incorrect records are not imported.

Analyzing records that are not imported

After importing a recipient list, you can download the non-imported records as a CSV file for each category described above. Use this file to manage the original list.

Cross-check for mailing dispatch

When you initiate a mailing, recipients are selected based on the following criteria and algorithms:

  • Recipients on a blocklist, unsubscribers, and recipients with a bounce overflow are not contacted.
  • Where applicable, target groups and maximum numbers of recipients are determined.
  • Email addresses are checked for correctness (see Incorrect data records).

After a mailing is sent out, responses are analyzed. Recipient addresses that produce a bounce generate an automatic reply to the return address. The replies are analyzed by Optimizely Campaign. Hard and soft bounces are counted separately for each recipient. A recipient who reaches the bounce limit for hard or soft bounces will not be contacted again. These recipients remain on the recipient list but are skipped when mailings are sent out (see Bounces).

Recipients who click the unsubscribe link are placed on the unsubscribe list. These recipients still appear in the recipient list but will not be sent mailings. The unsubscribe list records the email, a time-stamp, and the mailing the recipient received when he/she unsubscribed. These records make it easier to track cancellations – in the event of a complaint, for instance.

Cross-checking bounces

A bounce is generated whenever an email fails to reach a recipient's email server or mailbox. It informs the sender that the email could not be delivered.

Soft bounces

A soft bounce is generated when a mailbox is temporarily unavailable, such as when a mailbox is full and unable to accept more email until the user deletes some. Soft bounces seldom occur, because memory is usually large enough to handle a large number of emails.

Hard bounces

A hard bounce is generated when a server address or mailbox does not exist due to a technical problem (such as a server is down). A hard bounce is also generated if a mailbox no longer exists, which may have several reasons:

  • The email address is entered incorrectly (even though syntactically correct).
  • The user canceled the email account.

Bounce counter and bounce limits

Bounce limits for soft and hard bounces are set when configuring the client. The standard limit is three hard bounces or five soft bounces. Once reaching this limit, the recipient receives no more mailings. Bounces are counted across clients for each recipient.

  • How can I see how many bounces a recipient has generated?

    You cannot view bounces from the Optimizely Campaign user interface but you can retrieve the number of bounces via the Optimizely Campaign REST API. If you use the SOAP API, the getBounceCounter method also shows the number of bounces.

  • Can I view recipients who have generated a bounce overflow?

    You cannot view bounced out recipients from the  Optimizely Campaign user interface. However, you can use the Exporting recipients by category feature to download bounced out recipients as a CSV file. Contact customer support for assistance.

    You can also use the Optimizely Campaign REST API to get information whether a recipient has exceeded the bounce limit. If you use the SOAP API, the isBounceCounterThresholdExeeded method also shows if a recipient has exceeded the bounce limit.

  • Can I reset the number of bounces generated by the recipient?

    You cannot reset a recipient's bounce count from the Optimizely Campaign user interface. To reset the bounce count, contact customer support. But you can reset the bounce count via the Optimizely Campaign REST API, or if you use the SOAP API, the resetBounceCounter method also resets the bounce count to 0.

  • If an email account cannot be contacted, does it matter whether and how often I send mailings to it? It may be reactivated at some point.

    That may be true in theory. In practice, however, mailings to unavailable or non-existent emails are saved and analyzed by the internet service provider. If a sender sends too many emails to unavailable addresses, the provider places the sender on a blocklist and treat those emails as spam. So, it is better to stop mailings to a recipient who generates three/five bounces.

Cross-checking blocklists

Blocklists contain recipients who should not be contacted, including recipients who have submitted complaints, but also known spam traps and postmaster accounts which are standard for every email account.

Blocklist hierarchy and delegation

Depending on the how a client is structured, it can have one or more blocklists. Entries in a blocklist are inherited by sub-clients from main clients. If you lack authorization to access the main client, you cannot view its blocklists. The main client blocklists also apply to the sub-clients.


Blocklists, unlike recipient lists, can use placeholders. For example, you can block a domain. So while a recipient's email address is not specifically on the blocklist, a recipient's domain can block the recipient.

  • Can I define a blocklist for a single recipient list?

    No. A recipient list applies across clients.

  • Can I view blocklist entries in higher level blocklists?

    You must have authorization to access a higher level client.

  • Can I prevent a blocklist from being inherited by sub-clients or define exceptions?

    No. Blocklist entries are inherited by sub-clients. You cannot circumvent this type of inheritance. Also, you cannot define exceptions for blocklist entries.

Cross-checking unsubscribe lists

Recipients who unsubscribe from a mailing by using an unsubscribe link or de-registration form are marked as unsubscribed. However, they are remain on the recipient list. When a mailing is sent, these recipients are filtered out.

  • Can I view the unsubscribe list in my client?

    You may not view unsubscribe lists using the Optimizely Campaign user interface. There are several ways to retrieve unsubscribers.

    1. Using the Download unsubscribers feature, download an unsubscribe list as a CSV file through the user interface.
    2. If you are using the REST API, use the GET method to retrieve information about all unsubscribes.
    3. If you are using the SOAP API, use the contains and containsAll methods to query whether one or more recipients are on an unsubscribe list.
  • Can I configure an unsubscribe list so that it only applies to one recipient list?

    Yes. You can set up an unsubscribe list based on a recipient list. Whether it makes sense to do so depends on the recipient list and how a client is structured. Contact customer support for assistance.

  • Can I use the  Optimizely Campaign user interface to place a recipient on the unsubscribe list or remove him/her from it?

    No. Only the recipient can complete the unsubscribe process. To rescind an unsubscription, the recipient must re-register (by using the opt-in option, depending on the configuration).

  • Can I unsubscribe a recipient by deleting him/her from the recipient list?

    If you deleted from the recipient list, the recipient no longer receives mailings from this list. If appearing in multiple lists, however, the recipient will continue to receive mailings via the lists from which the recipient is not deleted.

    You should not delete a recipient from the list because the recipient's de-registration is not recorded, so the recipient can be added to a recipient list again. This can result in a complaint if the recipient continues to receive mailings after unsubscribing.

  • I manage my recipient list myself and import it to  Optimizely Campaign prior to each mailing. What should I keep in mind when doing this?

    Make sure that you import only active recipients into the recipient list. Import unsubscribers into the unsubscribe list so that the cross check can take place before dispatch.

    You also can use specially designed jobs/services to import unsubscribe lists or multiple lists. These jobs/services are not accessible via the Optimizely Campaign user interface. The lists are transferred onto the Optimizely Campaign server per SFTP and automatically imported to the client:

    • Importing an unsubscribe list. Import your local unsubscribe list to the unsubscribe list on your client.
    • Importing recipients including unsubscribers. Import an individual recipient list that contains active recipients for a variety of recipient lists and unsubscribers. The status of a recipient, or the list to which it is being imported, must be entered in a separate recipient list column to keep your lists consistent.

    Contact customer support for configuration of jobs/services. Imported data must have a defined name and be stored in a defined directory per SFTP.