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Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
Beeble - The Beeble Project is email and online cloud storage platform with unprecedented security and privacy without third party access.
Hiver - Manage Customer Support, Sales and Projects right from your Gmail inbox. Collaborate with Shared Labels, Shared Contacts, email notes, email reminders and email templates
Encipher.it - Encrypting email with Encipher.it is a simple way to protect your sensitive data.
MailClark - The Slack bot for external communications