What is this then?

Not all devices support unicode characters equally – either directly or as @font-face fallbacks.

I was hoping that someone had created a site that showed which were the safest to use.

I couldn't find that site, so I decided to make it.

I hope it's useful.

How thorough is it?

Well, currently there are 107 unicode characters tested on 78 browsers & devices, and 5 screen readers.
I'm aiming to constantly add to this.

Got any quick tips?

I have.

Using the 3 horizontal line 'burger' icon for your navigation? Use 2261 (≡) (96%) instead of 2630 (☰) (58%)

Using a unicode character as a fallback for an @font-face icon? Stay away from 1F374 (🍴) and above – only 55% support.

For non-emoji characters, there's no difference between specifying the character using its decimal or hex values, or adding it as css :after content (where the browser supports :after obviously).
For emoji characters some devices won't render the character when using css :after content.

Here's a few of the most well supported characters:

Get started

Check a unicode character: