Every platform has different emoji requirements. Getting them wrong means your emoji either won't upload or will look terrible on one platform while perfect on another. Here's the complete specification breakdown, so you don't waste two hours troubleshooting a 300KB GIF.
Platform-by-Platform Requirements
Discord
Format: PNG (static) or GIF (animated)
Size: 128×128px minimum, 256×256 recommended. Discord is generous, but don't go smaller than 128 or it looks jagged.
File size: under 256KB. Animated GIFs hit this limit fast. Keep your animation to 8-12 frames maximum, and optimize ruthlessly.
Nitro users see animated emoji; free users see a static frame. This is not a dealbreaker, but it means your animation should still read as something meaningful on the first frame alone.
Upload limit: each Discord server can have 50 emoji free, 250 with Nitro. Most communities never hit this, but it's worth knowing.
Slack
Format: PNG, JPG, or GIF. Slack is flexible here.
Size: minimum 128×128px. Slack auto-resizes, but give it at least 128 to work with. Slack recommends 128×128 as the sweet spot.
File size: under 1MB. You have more breathing room than Discord. Animated GIFs are fully supported for all users—everyone sees the animation, not just subscribers.
Scope: custom emoji are workspace-wide, not channel-specific. Once you upload it, anyone in the workspace can use it.
Microsoft Teams
Format: PNG recommended (GIF works but less stable).
Size: minimum 100×100px, recommended 256×256px. Teams is also flexible but start higher than you think you need.
File size: under 1MB.
Scope: custom emoji are organization-wide. Anyone in your Teams tenant can use it. This is a bigger organizational reach than Slack per-workspace emoji.
Important distinction: Teams also has native animated emoji built into the platform (separate from custom uploads). If you're uploading custom, stick to PNG for stability.
Twitch
Format: PNG only. Twitch does not support animated emoji emotes. This is a real limitation if you're used to Discord and Slack.
Size: Twitch requires three versions. Upload the 112×112px version and Twitch auto-generates 28×28 and 56×56. Do not upload all three separately unless the platform specifically asks.
File size: under 25KB. This is tight. A 112×112 PNG with gradients or complex shapes hits this limit fast. Simplify.
Aspect ratio: 1:1 (square). Non-square uploads will be rejected or distorted.
Common Export Mistakes (And How They Wreck Your Emoji)
Mistake 1: Forgetting transparent background
PNG supports transparency; JPEG does not. If your emoji has irregular shapes (not a perfect square), use PNG. Export JPEG and you'll get a white or colored box around your emoji, making it look like a sticker on top of the chat. Ugly.
Every platform accepts PNG. None of them care if you use it. Use PNG.
Mistake 2: GIF file size over platform limits
A 20-frame GIF at 256×256 can easily be 400KB. Discord won't take it. You need to cut frames or reduce dimensions. Ezgif.com has an optimizer that strips metadata and compresses, often saving 30-40%.
Mistake 3: Exporting at 64×64 when platform expects 128
The math looks backwards: smaller file size, right? Wrong. Slack and Discord scale up tiny images and they look blurry. Start at 512×512, export down to platform requirements. Never start small and scale up.
Mistake 4: Not testing on the actual platform
A GIF looks perfect in your preview. You upload it to Discord. It stutters. Turns out Discord's GIF decoder has quirks. Test before declaring it done.
The Optimization Workflow
Start at 512×512px (this is your master file).
For static emoji: export as PNG. Ensure transparent background. Check it at actual size on the platform.
For animated emoji: export as GIF. Keep under 12 frames. Use Ezgif to optimize (removes unnecessary metadata, compresses palette). Test file size before uploading. If it's over limit, reduce frame count or use a lower color palette.
Convert for multiple platforms if needed: a 256×256 PNG for Discord can be resized to 128×128 for Slack, no quality loss since you're going down.
These Microsoft Teams emoji are production-ready at multiple sizes and frame rates. Notice the smooth loops, the file sizes that don't choke the platform, the clarity at small sizes. That's what proper export looks like.
The Real Question: Manual Export or Automated?
If you're uploading five emoji, do it manually. You'll learn the quirks fast.
If you're uploading fifty or need consistency across platforms, use a tool that handles format conversion and optimization automatically. EmojiCreator's Discord Emoji Maker does exactly this—you feed it a PNG, it handles resizing, optimization, and format conversion. You get the same emoji tweaked for each platform automatically.
Skip the technical headaches. Use Discord Emoji Maker to handle the platform-specific formatting, so your emoji look pristine everywhere.