Video: Slack vs Trello

Slack brings all your communication together in one place. It's real-time messaging, archiving and search for modern teams. Create open channels for the projects, groups and topics that the whole team shares. Slack searches whole conversations, not just individual messages, so you can find what you’re looking for no matter who said what or when they said it. Slack free open-source (self-hosted) alternatives are: Mattermost, Rocket.Chat, Zulip
Get organized as fast as you can think. The easy-to-use interface takes no time to learn, and every action is instantaneous, so there’s nothing standing between you and your sweet productive flow. Trello is great alone, but even better with others. Get the whole group onboard in seconds. See their updates in real time. Free Trello alternatives are Bitrix24, Producteev, Remember the Milk. If you are looking for self-hosted open-source Trello alternative, pay attention to Taiga and Wekan.