---
description: What icons are, and how to customize them.
title: Icons
image: images/blockly_banner.png
---

# Icons

Icons are used to define certain UI elements that show or define "meta"
information about a block. Usually this means they act as a clickable button
that opens a pop up with more information or an editor.

→ More info on [Fields vs Icons][fields-vs-icons].

Blockly provides some built-in icons that fulfill common use cases, like adding
comments or warnings to blocks. You can check out the [reference
documentation][icons-reference] for more information about those.

Blockly also lets you define your own custom icons if the built-in ones don't
serve your use case. For example, you might want an icon that displays version
or copyright information in a pop-up bubble.

→ More info on [Creating custom icons][custom-icons].

[fields-vs-icons]: /guides/create-custom-blocks/fields/fields-vs-icons
[custom-icons]: /guides/create-custom-blocks/icons/creating-custom-icons/basic-implementation
[icons-reference]: /reference/blockly.icons
