Telegram is a cloud-based messaging app with a native macOS client. It's for people who want fast messaging that syncs across phones, tablets, and computers without needing a phone connected.

Key features:

Access your messages from all your devices at once, and start typing on one and finish on another.
Send media and documents of any type, up to 2 GB each.
Create group chats with up to 200,000 members and set up bots for specific tasks.
Use Secret Chats when you want extra privacy.
Delete any message you sent or received for both sides at any time.
Customize the app with themes, animated stickers, and emoji.

Telegram for macOS is available on the Mac App Store and as a direct download, and it requires macOS 10.13 or later. The app is free and open source under GPL v2, with apps for iPhone, iPad, and Android too.