Opera Mail uses one database that keeps an index of all mail, and sorts the messages automatically into several "views" or accesspoints. Messages are automatically sorted by type, such as mailing lists, and mail with attachments . This approach to indexing allows for quicker access to messages. For instance, a message sent to a mailing list with a word document attached will appear in both the "Documents" attachment view and in the "Mailing lists" view. Opera Mail can also use Bayesian filtering to automatically sort messages into other views. All messages in the database are accessed by opening the "Received" view.
The integrated mail component included a simple IRC client, but this is no longer present in the standalone program. The IRC client supported multiple servers, file transfers, and interface customization through CSS.