Look at what your plugin documents. EssentialsX and most chat plugins read &#RRGGBB, Paper and Velocity plugins read MiniMessage, and older Spigot plugins read &x&R&R&G&G&B&B.
Why do I see codes instead of colours?
The plugin does not understand that format, or the server runs Minecraft older than 1.16, which has no hex colours. Try another format from the list.
Why is the output so long?
Each character gets its own colour code, so a gradient is many times longer than the text. Spaces get no code. MiniMessage stays short because the plugin calculates the gradient itself.
Do emoji and special letters work?
Yes. The tool colours whole characters, so umlauts, accents and emoji stay intact. Whether Minecraft shows an emoji depends on the font of the game and resource pack.
Is my text saved?
Only in your browser, so it is still there next time. Nothing is sent to our server.