Disable Add Card — Power-Up

This Power-Up hides all "Add a card" buttons on your Trello board using CSS injection.

Setup (self-hosted):

  1. Host these files on any static server (GitHub Pages, Netlify, Vercel, etc.)
  2. Go to trello.com/power-ups/admin
  3. Click New → enter your hosted URL as the Iframe connector URL (pointing to connector.html)
  4. Add the Power-Up to your board

What it does:

Since Trello Power-Ups run in sandboxed iframes and can't directly modify the board DOM, this Power-Up takes a different approach: it provides a board button that signals the feature is active, and relies on a companion user script or browser extension to inject the CSS that actually hides the buttons.

For guaranteed results, paste the CSS below into a browser extension like Stylus targeting trello.com:

See inject.css in this folder for the ready-to-use stylesheet.