100% Local · No Upload · No Watermark
Slack Emoji GIF
Make a custom Slack emoji from any GIF — 128KB max, 128×128 square. We crop, scale, and compress locally so it actually uploads. No account, no upload to us.
Locked to 128 KB · 128×128
px
Will crop centered to a 128×128 square.
Advanced
Why a dedicated Slack emoji page
Two constraints, one tool: 128 KB and a square crop.
Slack's actual rules
Slack custom emoji must be ≤128 KB and ≤128×128 px. Bigger = upload rejected.
Crop, scale, compress — in one go
Most GIF compressors don't handle the square crop. We do, locally.
Other platforms differ
Discord server emoji is 256 KB. Twitch is up to 1 MB. We have pages for those, too.
How it works
1
Drop your GIF. Any size, any aspect ratio.
2
We crop center to square, scale to your px value, then binary-search lossy + colors locally to fit your KB target.
3
Download — upload as a Slack custom emoji.
Frequently asked
What are Slack's exact emoji rules?
Animated emoji must be ≤128 KB, max 128×128 px, and must be square. Slack accepts .gif, .png and .apng. Anything bigger is rejected at upload time. Workspace admins can sometimes restrict emoji creation, but the file rules are workspace-independent.
My emoji uploads but doesn't animate — why?
Slack drops animation if total frames + colors are too heavy after their re-encode pass. Try the "Allow shorter loop" toggle (default on), or open Advanced and reduce colors. Short, simple loops survive Slack's pipeline more reliably.
Can I use a non-square px value like 96×128?
No — Slack requires square emoji. We always center-crop to square before scaling. The "Square edge" input controls the single edge length used for both width and height.
What about Discord, Twitch, Mastodon emoji?
Discord server emoji is 256 KB (use /compress-gif-to-256kb). Twitch is up to 1 MB on free tier and 3 MB for partners. Mastodon ranges from ~50 KB to 200 KB depending on instance — use /reduce-gif-size with the right custom target.
Free? Account? Watermark?
Free, no account, no watermark. The tool is funded by the optional gifcompressor pro tier (batch processing and a CLI).