How Does the Postbox 5 Email Program Work?

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Postbox, Inc.

Postbox is a mighty polished Mozilla Thunderbird that brings together fast and ubiquitous search, the powerful Mozilla Thunderbird email underpinnings and conveniences such as flexible email templates and some social network integration. For all its shine, Postbox retains some Mozilla Thunderbird idiosyncrasies while task management, self-learning automation, and social networking sites are embraced but not fully.

What We Like
  • Postbox offers a complete email experience competently handled.

  • Fast search lets you find related messages, files, images, and people.

  • Postbox groups email intelligently; free-form topics help you organize and concentrate on them.

What We Don't Like
  • Postbox does not fully exploit topics and social network integration.

  • Task management is minimal and does not include an integrated calendar.

  • Keyboard shortcuts are a bit incoherent and settings hard to find.


  • Postbox lets you access and manage POP and IMAP email accounts as well as RSS news feed subscriptions and Usenet news.
  • Fast search, free-form topics (with support for Gmail labels), traditional folders and to-do/pending marks help you organize and find mail.
  • Postbox quickly finds attachments, images (with previews) and links, too; everywhere, within a message and while composing.
  • Integration with social networking and microblogging sites lets you post to the web while Postbox fetches mug shots, company names, and job titles for contacts.
  • Postbox can use tabs to keep folders, topics and messages open. A conversation view collects threads, quoted text hidden.
  • A trainable spam filter spots junk, and rules let you automate Postbox in many ways (e.g. to move and delete mail or reply). To help protect your privacy, tracking images (which let email marketers know when you open a message, for example) can be blocked.
  • For new mail and replies, you can set up multiple signatures and canned replies including fields that expand with the current date or the recipient's name. Postbox includes a set of typical business email templates.
  • An easy to use editor lets you format text and images (to shrink them to comfortable size) with rich options. At the same time, an HTML editor with syntax highlighting lets you edit the source of emails you send directly.
  • Files can be sent as attachments, of course, but also as Dropbox links. You can also integrate Postbox with notebooks such as Evernote or task managers like Remember the Milk to turn emails into to-do items or notes, for example, in one easy step.
  • Postbox makes it easy to set up common account types and sports a unified inbox (which still distinguishes accounts if desired).
  • You can expand Postbox with (at least certain) Mozilla Thunderbird extensions such as Lightning to add a calendar.
  • Postbox supports Windows XP/Vista/7/8/10 and Mac OS X 10.6/7/8/9.​

Expert Review

If you've used Mozilla Thunderbird before, you'll feel at home in Postbox. But you'll also find well-known nooks decked out like a spa, pieces from the Apple Store in the odd corner and familiar fronts from the facebook here and there.

Postbox's polished interface makes it a joy to use — and, for the most part, is effectively approachable, too. Search, for instance, is fast and reasonably intelligent. You can search for keywords or criteria everywhere or in specific folders and get results in seconds; a filtering bar makes focusing on certain senders or topics (more about these later) a snap. Postbox also helps you find related emails, files or links when you read a message — or compose one.

Help Composing Mail

Speaking of files and composing: Postbox lets you attach files to emails, of course; you can send links to Dropbox files just as easily, though, which is fabulous whenever you've already uploaded a file to Dropbox and don't need another copy in your "Sent Items" folder. Canned messages and multiple signatures also help with composing messages. Postbox could be more perceptive, though, and insert the recipient's name in a greeting, for instance.

Building the index needed for Postbox's searching prowess takes an initial effort, of course. Depending on the size of your email archive, the process can be lengthy. Thankfully, Postbox indexing happens automatically when you idle away from your computer. Eager for results, you can also trigger manual indexing — which, unfortunately, cannot run in the background. It's also a pity that searches cannot be saved as smart folders easily. Postbox does retain Mozilla Thunderbird's virtual folders, of course.

The Gmail Approach

Speaking of email archives, Postbox takes the Gmail approach. An "Archive" button moves mail from inbox to a single big archive folder. Search is always there to pull out what you need. Afraid no search will collect just the messages you need? You can label mail freely in Postbox with topics — and use these like folders, or as search criteria. (If you do use a Gmail account, Postbox lets you use Gmail labels like its own topics — and the "Important" label gets special treatment, too.) Postbox also lets you add notes to messages, edit their subjects and even alter the content.

Archiving is not the only cue Postbox has taken from Gmail. Instead of listing threads as one message after the other — interesting new bits hidden under globs of quotations — Postbox creates a coherent conversation that just shows new information by default. Next to the conversations or message, you'll also note some — hopefully key — pieces extracted for easy access: addresses linked to a map, images with previews, attached files, and links for following. Finally, signature links take center stage.

Managing Mail, Events, and Tasks

A handy button marks messages as "To-Do", and some clever clicking puts them into a grayed out pending state. Unfortunately, Postbox does little beyond subtle hints to help you with the doing and waiting, or at least organizing the tasks. An integrated calendar or alert system are missing, and changing a to-do item's status relies on a tad crude editing. Postbox does detect dates, though, and lets you set up events in iCloud Calendar, Google Calendar or Lightning easily.

Postbox filters spam with reasonable accuracy. It's a pity the classifier is not leveraged for assigning topics — or suggesting replies and groups, for example. Integration with social networks could also go farther. Postbox does retrieve images, company names and job titles and lets you post to select sites, but does not otherwise integrate conversations on these sites.