Spark is an email app for Mac featuring a modern design that's fast, intuitive, and collaborative.

Features:
Smart Inbox lets you quickly see what's important in your inbox and clean up the rest. All new emails are smartly categorized into Personal, Notifications, and Newsletters.
Invite teammates to discuss specific emails and threads. Ask questions, get answers, and keep everyone in the loop.
For the first time, collaborate with your teammates using a real-time editor to compose professional emails.
Schedule emails to be sent when your recipient is most likely to read them. It works even if your device is turned off.
Snooze an email and get back to it when the time is right. Snoozing works across all your Apple devices.
Powerful, natural language search makes it easy to find that email you're looking for. Just search the way you think and let Spark do the rest.
Smart Notifications filter out the noise, letting you know when an email is important, saving you from notification overload.
Integrate Spark into your workflow and take productivity to the next level. Supports Dropbox, Box, iCloud Drive, and more.
A full-featured calendar works right in your email to help you always be on top of your schedule. Create events easily using natural language.
Create secure links to a specific email or conversation. You can share the link on Slack, Skype, CRM, or any other medium, so your team can see it and collaborate around it.
Before you send an email, quickly swipe to choose the right signature for the occasion.
Quick Replies get the point across with just a tap. Love, like, or acknowledge an email in an instant.