Export is an easy to use Slack add-in for allowing you to download archives of all your Slack discussions. You can export all types of Slack messages, including:
Messages can be archived as either HTML, JSON, or plain-text for easy readability. Additionally, you can limit by date range too.
Have your Slack administrator install the Export app:
From any Slack channel, private group, or direct message, simply type:
That's it! From there you can download a full, chronologically-sorted archive of all messages in JSON, HTML, or plain-text.