About

mail.app (also known as Mail.app or Apple Mail) is an email program included with macOS. Originally developed by NeXT as NeXTMail, a part of their NeXTSTEP operating system, it was adapted to become macOS' Mail application following Apple's acquisition of NeXT.

The current version of Mail utilizes the smtp, pop3, and imap protocols, and supports yahoo, AOL, gmail, icloud (formerly mobileme) and exchange. ios features a mobile version of Apple Mail, mobile-mail.

File System Directories

Mail stationary templates are stored in the following directory on macOS 10.13

/Library/Application\Support/Apple/Mail/Stationary/Apple/Contents/Resources/

Databases for each folder and each account within Mail are stored in the following directory on macOS 10.13

~/Library/Mail/V5/

Plugins

OS X 10.8

• ReplyWithHeader - Customize the reply/quote format/message
• GPGMail - GPGMail plugin.
• Delete2Archive - Remap DELETE key to ARCHIVE in Apple Mail for better Gmail folder compatibility.
• MailPluginFix - Fix Apple Mail plugin compatibility issues.
• Send Later - Schedule time-dependent emails for sending at a later time.
• NoFlaggedMailbox - Remove the Flagged mailbox from Apple Mail Mountain Lion.
• DesktopOne - spam filter for Mail.app and Outlook 2011.
• CargoLifter - Uploads attachments to the cloud, and adds the corresponding links to the end of your email.
• Face2Face - Adds new sources for sender images like Facebook, Gravatar, as well as its own image database.
• Emoticons - Add emoticons to emails.
• ComposeIT - Toolbox to enhance composing and replying to messages.
• Attachment Tamer - Increased control over attachment handling.
• ForgetMeNot - Scans email for special keywords referring to attached files and reminds you if it cannot find an attachment when you try to send your email.
• DockStar - Add badges to the Mail dock icon and click-able indicators to the menu bar.
• MailHub - Helps you organize your email more efficiently
• AttachmentsMenu - Indexes all Apple Mail messages that contain attachments and offers access to them via the menu-bar
• Meta - Harness spotlight right inside Mail (custom keywords-driven smart folders) for better email management
• FlaggedMails - Keep track of your flagged emails via the menu bar. Universal Mailer - Assists with solving sending email issues such as inline attachments/images, and configuring the default font for outgoing messages.
• Growl Mail - Notification system.
• Mail Clips - Copy attributes of multiple mail messages, add sender addresses to Address Book.
• Letter Opener - Access Microsoft Outlook winmail.dat files.
• MailRecent - Adds "Copy to Recent" and "Move to Recent" menu items.
• MailFollowup - Adds a "Follow Up" item to a Message and contextual menus.
• Herald - Growl-like notifications.
• Eaglefiler - File your mail and other things.
• SpamSieve - Spam filter.
• Signature Profiler - Control signature-selection behavior
• Mail Act-On - Keyboard organization for Apple Mail.
• MailTags - Better organization of email.
• QuoteFix - Position the cursor below the original message instead of above it
• MsgFiler - Keyboard-driven quick filing of email.

OS X 10.6

• Unsubscribe - Adds unsubscribe button via unsubscribe.com
• Related Mail - Display related messages to viewed email.
• mBoxMail - Hotmail support.
• Mail Perspectives - Compact view of your email.
• Mailboxer - Smart Mailboxes for your contacts.
• Mail2iCal - Generates an iCal event or to-do item of the selected message.
• MailHub - Helps you organize your email more efficiently
• MsgFiler - Keyboard-driven quick filing of email.
• MessageFont - Configure default font for Rich Text messages
• TruePreview - Customize message status behavior
• Mailtabs - Add Safari-style tabs.
• GPGmail - Encrypt and/or authenticate email
• Archive - Adds a keyboard shortcut and toolbar button for archiving messages.

OS X 10.5.x

• Flagit! - Labels and colored flags.
• Letterbox - Vertical columns.
• HTTPmail - Hotmail and MSN support
• Related Mail - Display related messages to viewed email
• Growl Mail - Notification system
• WideMail - Provides wide-format view option
• MiniMail - Process mail from a tiny window
• Eudora Mailbox Cleaner - Eudora to Mail migration.
• Attachment scanner - Avoid the embarrassment of missing attachments
• WideMail - A wider view.
• MailAppetizer - Email notification.

OS X 10.4

• IMAP-IDLE - Adds IMAP-IDLE support.