Can I limit user's permission so he can only press buttons and comment?

[Rafastesia]

I'm graphic designer and I'm using Trello for my clients approvals. My intention is to have controll over all the workspace and cards, and have my client as a viewer who only can comment and press some automated buttons created by me, so they can approve one design or ask for a revission just by commenting or pressing buttons, and not ruining the rest of the card.

Is it that possible?

And is it possible to show or hide a specific button depending on the user who is viewing the workspace?

Thanks!

[Gaurav Kataria · Accepted solution]

You can add them Observers on your board  https://support.atlassian.com/trello/docs/adding-observers-to-boards/

Observers can comment on cards but cannot move or edit cards, upload card attachments, tick the box on a checklist item, and also they can't change board settings.