The Codes Table - found under Settings > Advanced Settings > Developer's Corner - contains the IDs of Lists, Groups, and Recipient Fields that you will need when retrieving or updating information in MailUp via forms and/or the MailUp API.
Provides the following details about Lists that have been created in your MailUp account:
Provides the following information about Groups that have been set up in your account:
Provides information about the custom recipient fields setup in your account:
Examples of situations in which you will need to consult this page are: