BlueMail

BlueMail is a free, beautifully designed, universal email app, capable of managing an unlimited number of mail accounts from various providers.

It is the best third party email app out there that saves you the stress of shuttling between various email Apps.

I own up to four different email account for various purposes so Blue Mail has helped me get all my mails in one place.

Other features include:

Integrated Calendar
Easy Groupings
People Centric Mailbox

BlueMail can work across different devices

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