The 12 Most Popular macOS Mail Add-Ons

Use these popular add-ons to extend your mail capabilities in macOS

Apple Mail comes equipped with everything you need in an email client, but superusers may want enhanced features. Mail add-ons offer advanced labels, simplified interfaces, new message notifications, versatile filters, enhanced security, artful stationery, and a whole lot more. Here are the most popular Mac Mail add-ons.

Information in this article applies to the Mail app in macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12), as indicated.

01
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MailSuite

MailSuite 2019 for macOS Mail
What We Like
  • Contains four plug-ins.

  • Has a good installation tool.

  • Have the option to add some or all plug-ins.

What We Don't Like
  • Relatively expensive.

  • When the software upgrades, a new subscription fee is necessary.

  • Poor documentation.

MailSuite includes four powerful components: MailTags, Mail Act-On, Mail Perspectives, and SigPro. With these components, you can add tags, keywords, notes, and due dates to emails in macOS Mail.

The MailTags component integrates tags with search, rules, smart mailboxes, Calendar, Reminders, and project-management software for near-perfect and semiautomatic custom email organization.

MailSuite includes Act-On, a Mail plug-in that saves time with keyboard shortcuts. You can set up shortcuts for labeling, moving, or redirecting messages.

Mail Perspectives offers a customizable compact window design that keeps your most important email visible but not in your face as you work.

With SigPro, you create a signature one time and then customize it by calling a script.

MailSuite costs $60.

It is compatible with macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

02
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Mailbutler

MailButler for macOS
What We Like
  • The plug-in bundle has a separate tab in Mail preferences.

  • Adds an avatar to messages to identify senders quickly.

  • Schedules outgoing messages.

  • Has Undo Send feature.

What We Don't Like
  • The free account is limited to 30 actions per month.

  • Doesn't support OneDrive.

  • New buttons make Mail look cluttered.

The MailButler Mail extension is a Mail productivity suite that includes tracking, signatures, and scheduling features. MailButler quickly turns emails into tasks and reminders.

With MailButler, you can make templates from your frequently sent email messages to save time and generate follow-up reminders so that you don't forget important opportunities.

Mailbutler offers a 14-day free trial and three plans, one of which is free with limitations.

MailButler works with macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

03
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MailSteward

MailSteward for macOS
What We Like
  • Archives email in a relational database on the Mac.

  • Powerful search feature.

  • Robust and reliable.

What We Don't Like
  • Frequent updates require additional fees.

  • Cluttered interface.

Use MailSteward to place years of email in a secure, searchable archive to keep your Mail inbox clean. MailSteward offers a speedy and multi-option search feature to find what you need when you need it.

A free 15,000-email archive version is available as are paid upgrades for bulk users. MailSteward Lite costs $24.95 and includes archiving for up to 100,000 messages. Two additional plans are available for power and enterprise users.

MailSteward is compatible with Mail in macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

04
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SpamSieve

SpamSieve for macOS Mail
What We Like
  • Outperforms Mac Mail junk filters.

  • Few false positives.

  • Reduces spam at installation and more after training.

What We Don't Like
  • Daunting setup.

  • Not as user friendly as it could be.

SpamSieve delivers superior Bayesian spam filtering to the Mail app. It's as easy to use as the Apple Mail junk-mail filters and can give you statistics you may find informative. It works with any email provider on your Mac.

SpamSieve features include:

  • Color coding that indicates the spam level of each message.
  • Customizable whitelist and blocklist.
  • Runs on a Mac and keeps spam off iPhone and iPad.
  • Integrates with the macOS Contacts app.
  • Notifies you only for the receipt of non-spam emails.

A free trial is available. The paid version is $30.

Compatible with macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

05
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Mail Designer 365

Mail Designer 365 for Mac
What We Like
  • Builds responsive emails.

  • Live previews on multiple devices.

  • No coding needed.

What We Don't Like
  • Expensive, subscription-based software.

  • Spotty tech support.

Mail Designer 365 is a subscription-based app that makes it easy to add professionally designed templates to emails in macOS. With templates and custom tools, it affords the casual and serious designer or marketer plenty of control and flexibility. Additionally, Mail Designer 365 integrates with Unsplash to provide access to thousands of license-free images.

A 7-day free trial is available. The cost for a basic Business plan is $30 per month per person, with annual discounts and Business Premium and Business Enterprise plans.

Mail Designer 365 works on macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

06
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GPG Suite

GPG Suite for Mac
What We Like
  • Reliable OpenPGP encryption.

  • Adds a lock button and a sign button to outgoing emails.

  • Integrates seamlessly with macOS Mail.

What We Don't Like
  • The free version is no longer available.

  • Slow to update for new OS versions.

GPG Suite is a complete email encryption service that includes a macOS Mail plug-in. It lets you sign and encrypt, verify, and decipher in-line and OpenPGP/MIME messages comfortably and flexibly. You can also use it to create and manage OpenPGP keys and import your colleagues' keys.

The free GPG Suite download includes a 30-day trial of GPG Mail. After 30 days, GPG Mail costs $23.90.

GPG Suite is compatible with macOS Catalina (10.15), macOS Mojave (10.14), and macOS High Sierra (10.13).

07
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MsgFiler

MSG Filer for macOS
What We Like
  • Robust keyboard-based email filing.

  • Fast search capability.

  • Customizable interface.

What We Don't Like
  • No filing suggestions.

  • Complicated installation process.

MsgFiler makes​ moving messages easy. It includes a folder selector that finds the mailbox you're looking for with a few typed characters. Simply type to filter down a list of mailboxes. Navigate Mail or move messages around without leaving the keyboard.

MsgFiler is available at the Mac App Store for OS X. For macOS, go to the developer's website, download two files, and follow the instructions to install the plug-in.

The cost of MsgFiler is $9.99.

MsgFiler works with macOS Catalina (10.15), macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

08
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MailHub

MailHub for macOS
What We Like
  • Send Later feature.

  • Filing suggestions.

  • Reminders for email actions.

What We Don't Like
  • No Catalina version and no announcement one is coming.

MailHub is a smart assistant for the Mail app. It learns as you work and auto-suggests possible filing locations. Use it to set reminders on emails for follow-up later. A Send Later feature allows you to schedule a date and time to send an email.

MailHub is compatible with Mail in macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12)

MailHub offers a 30-day unrestricted free trial. The price is $19 for a single user, $49 for a five-user license, and $89 for a 10-user business account.

09
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Letter Opener

Letter Opener for macOS Mail
What We Like
  • Converts winmail.dat files on the fly.

  • Install and forget. It just works.

  • Good support.

What We Don't Like
  • Yearly subscription.

  • Additional charges for upgrades.

  • No Catalina version.

Winmail.dat files can be a nuisance because these files prevent some users from opening email attachments accurately. Letter Opener for macOS Mail handles winmail.dat attachments as if it invented them, making included files and rich formatting available just like other attachments.

Letter Opener offers a 14-day free trial and costs $29.99 per year.

Letter Opener is compatible with macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

10
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Email Archiver Pro

Email Archiver Pro for macOS Mail
What We Like
  • Fast email archiving.

  • Archive all email or specific folders.

  • PDF of each email includes attachments.

What We Don't Like
  • Can't search the archive by date range.

  • No Catalina version.

Email clients aren't always great catalogs for the messages you've sent over the years. Sometimes you need a dedicated archive service to keep a record of your emails. Email Archiver Pro saves messages from macOS Mail as PDF files, including all layouts, headers, and attachments. With Email Archiver Pro, PDF archives are easily searchable and accessible.

Email Archiver Pro Personal edition costs $39.99. Business and enterprise plans are also available.

Email Archiver Pro is compatible with macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12).

11
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Ofaco

Ofaco for macOS
What We Like
  • Fast auto-completion based on email content.

  • Customizable with user's frequently used text.

  • Free plug-in.

What We Don't Like
  • No Catalina version.

Ofaco—short for old-fashioned completion—is an auto-completion service that bases its recommended words on text from the message window, rather than text from the macOS dictionary. This makes for a more contextually relevant auto-completion function.

Ofaco works with Mail in macOS Mojave (10.14), macOS High Sierra (10.13), and macOS Sierra (10.12)

The Ofaco plug-in is free. Donations are accepted.

12
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MailFollowUp

MailFollowUp for macOS
What We Like
  • Adds two follow-up options to Mail menus.

  • Fills in email fields accurately for follow-ups.

  • Free plug-in.

What We Don't Like
  • Tricky installation process.

  • No longer developed or supported.

  • No Catalina version.

MailFollowUp adds Follow Up and Follow Up All to the message and contextual menus in the Mail app and can also add an optional toolbar button. Use it to create follow-up quoted messages to all the To recipients or all the To, Cc, and Bcc recipients of the original message, quoting the original text. The add-on keeps the To, Cc, and Bcc addresses exactly as those addresses appeared in the original message.

MailFollowUp works with the Mail app in macOS Mojave (10.14), High Sierra (10.13), and macOS Sierra (10.12).

The plug-in is free.

MailFollowUp is no longer being developed or supported.