Using the free slack subscription? You'd notice that:

• You lose your messages after a while even pinned messages. That's ok(you're using the free version).
• New members just joining your workspace are not able to view the pinned messages.

I'm building a bot that:

• Saves every pinned conversations in a channel
• Post a summary of the pinned messages;
  • to a special #pinned_messages channel
  • to channel members emails
• creates a PDF summary of every pinned conversations and makes this PDF available when triggered by a slash command!
• Renders a html page with the pinned conversations

• Pinned messages are persisted in database.
• Pinned messages can be retreived and viewed on an endpoint provided by SecuredPinned.
• Pinned messages are delated routinely every 24hrs.
• Workspace logo is updated on change.

Tech Stack: Node.js, @slack/web-api