Using the mobile emoji keyboard renders "?" on other platforms


Using the mobile emoji keyboard renders “???” on other platforms.

When users use the internal Mattermost Emoji-System (typing : etc. or choosing from the emoji-List on the desktop client/desktop browser) everything looks good. But especially on mobile, users tend to just user their regular emoji keyboards.

There is potentially a combined Client-Backend-encoding problem. Clients send the Emoji Unicode to Server and somewhere on the way (Sending, Server-Side-Saving, or Delivering to others clients) there is a “translation” problem.

Original Twitter thread here:

Here are sample screenshots:

  1. MacOS-Mattermost-App (ver. 4.0.1)

  2. MacOS-Firefox

  3. iOS Classic App

  4. iOS RN App: You can see that the emoji rendered here work fine. However, those posted from the Android RN App render as “???” as well


Additional info from reporter:

Mattermost-Version: 4.9.2
Database-Version: 4.9.0
Database: mysql
Server OS: Debian GNU/Linux 8
My Desktop OS: macOS (High Sierra)
My mobile OS: iOS 11.4

But client versions vary much in our team. Have lot's of Android users plus Desktop Browser-only users. Windows 7 perhaps, don't know.


If there are additional questions regarding my case (I’m user “matze” in the screenshots above) just let me know.


Thanks @kraehenpost!

One proposal you can help with is to get the raw text of the emojis posted from Firefox and the Desktop app to see if they’re different:

  1. Post the set of emojis from above screenshot in Firefox.
  2. Edit the post in Mattermost, so you have access to the raw text. Copy and paste this into a text editor.
  3. Post the set of emojis in MacOS Desktop App.
  4. Again, edit the post. Then copy and paste the raw text into a text editor.
  5. Share the contents of the text editor here.

That way we can compare if the emoji posted from the Mac emoji keyboard on Mattermost MacOS app are different from the ones posted in Firefox. Can help give a clue.

You can do the same from the iOS app if you have the time :slight_smile:


Hey, I#m note quite sure if I’m doing the right thing here. Again: If I’m using the built-in Mattermost Emoji-Button, the results are Inter-platform-compatible. Problem only starts, when I’m using the OS-specific Emoji-Keyboards. For the tests you suggested, I see the Emoji-keyboard built-in in macOS (for both, the Firefox-port und the Mattermost-Desktop-App-Post. Having said this, here are my results, directly copied from the text editor:

Result from step 1-2:
Here’s a set of emojis posted from Firefox: :smiling_imp::imp::japanese_ogre::japanese_goblin::clown_face::poop:

Result from step 3-4:
Here’s a set of emojis posted from Mattermos Desktop App: :smiling_imp::imp::japanese_ogre::japanese_goblin::clown_face::poop:


And here’s how the test post render on iOS, first the Mattermost iOS-Classic-App and second the Mattermost current iOS App (see the two lines on the bottom):


Thanks @kraehenpost! This is great. Appreciate it! Minor ask, can you help paste the emojis above inside a code block by surrounding them by a backtick like:

` <emoji1> <emoji2> `

Our engineer was taking a look at the emojis, but seems like the forums are manipulating the emojis in some way.


okay, please have another look into the post above. I used the backticks as suggested.