Guides / Slack

How to Make and Add Animated Custom Emoji in Slack

Custom emoji are one of the things that make a Slack workspace feel like your team's own. A teammate's face spinning in celebration or bouncing with excitement says more in a thread than a thumbs-up ever could.

Slack displays emoji very small, so a good custom emoji is square, tightly cropped and light enough to load instantly. Slack's own guidance is that square images under 128 KB with transparent backgrounds work best, and that animated GIFs can include up to 50 frames. Every Gifmoji animation stays under that frame limit, and the Slack preset exports at 128×128 and re-compresses the GIF if it comes out over 128 KB.

Slack emoji requirements

Dimensions: Square; 128×128 px is the standard size
File size: Under 128 KB recommended
Formats: GIF, PNG or JPG
Animation: Animated GIFs up to 50 frames
Who can upload: Members by default; owners can restrict it to admins

Step by step: make it and add it to Slack

In Gifmoji, upload your photo, crop it tightly around the face or subject, and pick an animation.
Under Export, choose Slack and click Download. You'll get a 128×128 GIF sized for Slack.
In Slack on desktop, click the smiley-face icon in the message field to open the emoji menu.
Click Add Emoji, then Upload Image, and select the GIF you downloaded.
Give it a short, memorable name (this becomes its :shortcode:) and click Save.
Type :your-emoji-name: in any message or use it as a reaction. Everyone in the workspace can use it.

Make your Slack emoji

Tips for great Slack custom emoji

Crop closer than feels natural. At emoji size, a face that fills the frame reads far better than a full upper-body shot.
Turn on Remove background for overlay effects like Laser Eyes or Deal With It so the effect sits on the subject rather than a busy backdrop.
Pick names your team will guess. :alex-party: is easier to find from the picker than :img_2231:.
Use the Fast speed for reactions. Short, snappy loops read best at small sizes.

Troubleshooting

Slack says I don't have permission to add emoji

Workspace Owners and Org Owners can restrict who adds custom emoji. Ask an owner or admin to upload it for you, or to change the permission.

My emoji looks blurry or tiny

The subject probably takes up too little of the image. Re-crop so the face fills most of the square, then export again with the Slack preset.

The file is larger than 128 KB

Gifmoji automatically re-encodes with fewer colors when an export exceeds the preset's limit. If it is still too large, choose an animation with fewer frames or turn on background removal, since flat backgrounds compress much better.