A Matching ID is a unique identifier assigned to each mailing that we use to track and report on your email.

Setting up a Matching ID

Your email may already have a unique identifier that Return Path can use as your Matching ID. This is usually the case when you send through an email service provider that already works with Return Path. If not, you’ll have to set one up. Your first step is to send an email to the seed list. Your account representative can check to see if your email already has a unique identifier that can be used as a Matching ID, and if so, there is nothing more you have to do. Your account representative will let you know what your Matching ID is and you can also find it in the ID column of your Campaign Overview or Details pages. 

If you don't already have a Matching ID in your messages, the best thing to do is to add a new header that matches our default matching ID. If you cannot add a header to your email messages, you can work with your account representative to identify a header and value that may be used or you can add the Matching ID to the body of your email.

If you need to add a unique identifier for your Matching ID, follow these instructions:

1. Determine your Matching ID. The most important part of the Matching ID is the value and how it is used. The value of the Matching ID included in the message must be consistent, regardless of recipient, across all messages that you want to be tracked as a single seeded campaign. This means that a subscriber ID will not work.
2. Decide where you will put your Matching ID. It can be placed either in the header or body of email messages.
3. Format it correctly. The Matching ID pattern must include an identifier specific to your company, which is static, as well as the variable value which is assigned to the campaign. See below for direction and guidance on how to add Matching IDs to the header or body of the email.
4. Send a test campaign to the seed list. Make sure the unique text string that you used worked properly. Once you have added your Matching ID, we configure our system so that while we collect data, it looks for and pulls in your Matching ID.

Putting a Matching ID in the header

Matching IDs are implemented through the use of an X-header, which is a custom email header. Check your Mailing Transport Agent (MTA) or Email Service Provider (ESP) documentation for their requirements about adding an X-header to your outbound email.

The recommended syntax for the Matching ID X-header is explained below:

For the key or label portion of the X-header, use:

X-rpcampaign:

• The recommended syntax for the X-rpcampaign ID value is:
  
  ****++++++++++
  
  
• The asterisks represent alphabetical characters for your company name, such as acme for Acme Corporation. You can use between 2 and 90 letters.
  
  acme++++++++++
  
  The plus symbols represent a numerical, globally unique ID, meaning that it is unique to your company and the specific campaign. Date and time is effective, so we recommend it, but it’s important that the Matching ID is the same for all emails in the campaign. Please implement the date symbolically as yyyymmddhhmmss.
  
  
• You may use between 2 and 90 digits:
  
  acme20030812112803
  
  
• The complete X-header Matching ID being added appears as:
  
  X-rpcampaign: acme20030812112803

Note: When implementing the date and time in the X- value, make sure it is formatted with 0 fills. For example, 09/01/2003 01:02:03, not 9/1/2003 1:02:03.

Adding a Matching ID in the email body

If you cannot add the Matching ID in the email headers, you can add it to the body of the email. So the Matching ID doesn’t appear in the HTML, it should be implemented as a comment in the HTML section of the email.

The recommended syntax for the Matching ID text string is the same in the body and the header. To include it as an HTML comment, use the following syntax:

<!-- rpcampaign: acme20030812112803 -->