ChatFilter

A chat filter for Bukkit, Spigot and Paper, 1.7.2 to 26.3. It censors or stops swearing in chat and in chat-like commands, sees through the usual disguises, blocks links and spam, and needs nothing installed on the client. Unmodified clients get all of it.

Also for NeoForge: ChatFilter ReForged, the same filter as a server-side mod for Minecraft 1.21.11 and 26.x.

Version 3 is a rebuild of this plugin, sharing its filtering engine with that mod. Most of what was asked for in these comments over the years is in it. Upgrading from 2.x: swap the jar. Your config and word lists are carried over on first start, the originals are kept as backups, and your old block or censor behaviour stays as it was.

Silent by default

A caught word reaches other players as ####. The sender sees exactly what they typed and is told nothing, so there is nothing to argue with and nothing to work around. Staff with chatfilter.see read the original.

Prefer the classic approach? Every category can instead:

• REPLACE the word for everyone (!@$#, **** or cartoon swearing)
• SHADOW the whole line: a soft-mute where the sender sees it sent and nobody else sees it
• BLOCK it, with "Oi {player}! Mind your language!" if you like
• or just LOG it

Hard to get around

Capitals, accents, leetspeak (sh1t, $h!t), stretched letters (fuuuck), spelled-out letters (f.u.c.k, s h i t), self-censoring (f*ck), full-width and look-alike letters from other alphabets, zero-width characters, and colour codes hidden mid-word. List the plain word once.

Kind to innocent words

Part-word and whole-word lists, so ass catches neither class nor grass. There's an allowlist for the Scunthorpe problem, and regular expressions for anything the lists can't say. /chatfilter test <text> shows exactly what would be caught, by which entry, and what would happen.

Chat that arrives as a command

/msg, /tell, /w, /r, /me, /say, /mail send, /f chat, and anything else you list. msg * skips the name: only the message is judged, never the player name, so /msg Assassin hi works.

And the rest

• Links and IP addresses, including example dot com, with an allowlist for your own site and a permission for those who may post them
• Spam: shouting is lowercased, and repeats and floods are stopped
• Strikes that expire one at a time, and a ladder that can alert staff, warn the player, or run any command: mute {player} 10m, kick {player}
• Staff alerts with a per-person toggle, and a console log
• Edit the lists in game: /chatfilter add profanity.words …, saved to the config file
• Keyword replies. It still answers "eleven", and you can switch that off for good.

Permissions

Plain Bukkit permissions, so any permissions plugin can grant them. The 2.x names (chatfilter.canswear, canchat, reload) still work.

Configuration

plugins/ChatFilter/config.yml, every option commented. The defaults mask the classic word list silently, block links and floods, quieten shouting, and filter the usual private-message commands. The severe list ships empty: every server's is different, and nobody should get one they didn't choose.

Versions

Two files: 1.13 – 26.3 (+bukkit1.13-26.3) and 1.7.2 – 1.12.2 (+bukkit1.7-1.12). Tested on Paper 1.7.10, 1.8.8, 1.12.2, 1.16.5, 1.20.1, 1.21.11, 26.1.2 and 26.3. Open source (MIT): GitHub.