Explainer
What Is a Custom Emoji? A Beginner's Guide
A custom emoji is a small image you upload to a chat app to use as a reaction or inline icon. Here's how they work and how to make your own.
4 min read
A custom emoji is a small, square image you add to a chat app — like Slack, Discord, or Teams — and then use as a reaction or inline icon, exactly like a built-in emoji. Unlike the standard Unicode emoji set (😀, 🎉, ❤️), custom emojis are uploaded by you and can be anything: a mascot, an inside joke, a teammate's face, or a brand icon.
They're usually small transparent PNGs (or GIFs for animation) sized around 128×128 pixels, so they stay crisp in the emoji picker and as reactions.
How custom emojis are different from regular emojis
- •Regular emojis are a fixed, universal set defined by the Unicode standard.
- •Custom emojis are images you upload, unique to your workspace, server, or channel.
- •Custom emojis can be branded, personal, or topical — anything you can draw or generate.
- •They live only where you upload them (e.g. one Slack workspace or one Discord server).
Why teams and communities use them
- •Faster communication — one reaction replaces a whole sentence.
- •Culture and identity — inside jokes and rituals become 'official'.
- •Engagement — people react more when the emoji feel personal.
- •Branding — companies and creators reinforce their identity in chat.
How to make a custom emoji
- 1Describe the emoji you want in an AI generator, or pick a template and upload a photo.
- 2Download the result as a transparent PNG.
- 3Upload it to your app (e.g. Slack: Add Emoji; Discord: Server Settings → Emoji).
- 4React with it or type its name to use it.
Make your own custom emoji
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Open the emoji generatorFAQ
What is a custom emoji?
A custom emoji is a small image — usually a transparent PNG around 128×128 px — that you upload to a chat app to use as a reaction or inline icon, just like a built-in emoji.
Are custom emojis the same as stickers?
They're related. Emojis are small inline icons used in text and reactions; stickers are larger standalone images. Many platforms support both, and the same artwork can often be used for either.