Best Email Client Extension Software & Apps (2025)

Best Email Client Extension Apps and Services

Handpicked collection of the most popular and highly-rated Email Client Extension applications

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GPGMail

Open Source

GPGMail is an extension for Apple Mail that provides public key email encryption and signing.

Bluhell Firewall

Open Source

Bluhell Firewall is a lightweight Ad-Blocker and Tracking/Privacy tool.

Enigmail

Open Source

Enigmail is a data encryption and decryption extension for Mozilla Thunderbird and the SeaMonkey internet suite that provides OpenPGP public key e-mail encryption and signing.

Lightning

Open Source

Lightning App Builder is a point-and-click tool that makes it easy to create custom pages for Salesforce1 and Lightning Experience.

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Recently Added Email Client Extension Apps and Services

Latest additions to our Email Client Extension software collection

GPGMail

Open Source

GPGMail is an extension for Apple Mail that provides public key email encryption and signing.

Bluhell Firewall

Open Source

Bluhell Firewall is a lightweight Ad-Blocker and Tracking/Privacy tool.

Enigmail

Open Source

Enigmail is a data encryption and decryption extension for Mozilla Thunderbird and the SeaMonkey internet suite that provides OpenPGP public key e-mail encryption and signing.

Lightning

Open Source

Lightning App Builder is a point-and-click tool that makes it easy to create custom pages for Salesforce1 and Lightning Experience.