Mac heads looking for alternative email clients may have stumbled across Postbox at some point in time, which is renowned for lighting fast email searches, conversation views, its tabbed interface, and universal search that makes finding attachments a breeze. The full version is available for $39.95, but those looking to try out a lot of the same functionality may want to check out Postbox Express.

Something users have been asking for is extensibility. As of version 1.0.1 (released today!), Postbox Express now comes with Add-on support, language packs that you can install, and support for localized dictionaries. You can check out all the wonderful extensions on their official list of all things supported (a popular extension is Lightning).

Postbox Express isn’t just a lite version of Postbox. It’s a fully capable email client that’s as extensible as Thunderbird yet twice as functional. Be sure to download it here (direct link) and let us know what you think in the comments.