Telegram is a messenger that allows you to exchange text and voice messages and media files of many formats. It uses a proprietary server part with closed code, running on the capacities of several companies.

In addition to the standard exchange of messages in dialogs and groups, the messenger can store an unlimited number of files, maintain channels (microblogs), create and use bots.

Microsoft Teams — an enterprise platform that integrates chat, meetings, notes, and attachments into a workspace. Developed by Microsoft as a competitor to the popular corporate solution Slack.