There is a 3rd alternative...
Atolia, the one and only workspace your team needs
Atolia is a power-packed all-in-one digital workplace: Chat, Video calls, Tasks & Projects, Calendars, Documents, Notes...
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Why choose Nifty or Slack?
Both Nifty and Slack offer free versions and have add-ons, roles management, contact management, workspace, and user activity monitoring, as well as chat, file sharing, mentions, voice messages, groups/channels, GIFs, and emojis. However, Slack provides additional features such as graphic personalization, 1-1 video calls, group video calls, screen sharing, audio calls, recording, subtitles, translations, online document editing, document viewer, document management, notes-taking, calendar, and task management.
In terms of customer support and training, Nifty and Slack offer training resources, help resources, and training webinars. Nifty provides a dedicated Customer Success Manager (CSM), while Slack does not. Both platforms have mobile, web, and desktop applications, as well as integrations and APIs. Slack also offers on-premise deployment, SAML/SSO authentication, end-to-end encryption, two-factor authentication, and data/users import capabilities.