🔤 Spell checking

May 13, 2026 · View on GitHub

Komai underlines misspelled words as you type (in the message composer and the room topic editor) and offers corrections when you right-click a flagged word.

It is offline and uses the standard Hunspell dictionaries (the same .dic/.aff files LibreOffice, Firefox, and most Linux desktops use).

A copy of the English (US) dictionary is built in, so spell checking works out of the box on every platform without additional setup.

See a screenshot of 🖼️Spellcheck in action in the Composer textarea.

Contents

How it works

A word is flagged only when none of the enabled dictionaries recognizes it. That means you can enable several languages at once (say English and Bulgarian) and mixing them in a single message produces no false positives. Right-clicking a flagged word offers spelling suggestions, plus the option to add the word to your personal dictionary.

Komai discovers dictionaries from three places, and uses whichever it finds:

  1. the built-in English (US) dictionary (always present);
  2. a per-user hunspell/ folder in Komai's data directory (see Manual);
  3. the system Hunspell locations — /usr/share/hunspell, /usr/share/myspell/dicts, $XDG_DATA_DIRS/hunspell on Linux; ~/Library/Spelling on macOS — which also picks up dictionaries already installed for LibreOffice or other apps.

Choosing languages

Open Settings → Composer → Spellcheck:

  • Enable spell checking turns the whole feature on or off.
  • Below it, tick the languages you write in. Only the dictionaries Komai could find appear here — to add more, see the next section.

On first run Komai enables the dictionary that matches your system language, falling back to English (US).

Installing more dictionaries

A "dictionary" is a pair of files, <locale>.dic and <locale>.aff (for example de_DE.dic + de_DE.aff). Once Komai can see such a pair, the language shows up in the settings list — reopen the settings page (or restart Komai) after installing one.

Linux (native package)

Install your distribution's hunspell-<language> package:

DistributionCommand (example: German)
Archsudo pacman -S hunspell-de
Debian / Ubuntusudo apt install hunspell-de-de
Fedorasudo dnf install hunspell-de
openSUSEsudo zypper install myspell-de_DE

Package names vary by distro — search for hunspell (or myspell) plus your language. Komai also reuses dictionaries already installed for LibreOffice, so you may already have some.

Flatpak

Install the matching org.freedesktop.Platform.Hunspell.<locale> runtime extension from Flathub:

flatpak install flathub org.freedesktop.Platform.Hunspell.de_DE

The extensions for the languages you've configured in Flatpak (flatpak config --set languages …) are pulled in automatically when you install Komai, so for most people no extra step is needed.

Snap

The snap ships a small set of dictionaries baked in by the packager; because of strict confinement it can't read dictionaries installed elsewhere on the system. To add one yourself, use the Manual method — the data directory inside the snap is ~/snap/komai/current/.local/share/komai/.

macOS

There is no system Hunspell directory on macOS (the OS spell checker uses a different mechanism Komai can't read), so the built-in English dictionary is what you get out of the box. For other languages, use the Manual method, or install LibreOffice language packs and copy their .dic/.aff pairs over.

Windows

Same as macOS — there's no shared Hunspell directory, so use the Manual method for languages beyond the built-in English.

Manual (any platform)

Download a <locale>.dic and <locale>.aff pair — the LibreOffice dictionaries repository has them for dozens of languages — and drop both files into a hunspell/ folder inside Komai's data directory:

Install typePath
Linux (native)~/.local/share/komai/hunspell/
Flatpak~/.var/app/cc.etke.komai/data/komai/hunspell/
Snap~/snap/komai/current/.local/share/komai/hunspell/
macOS~/Library/Application Support/komai/hunspell/
Windows%LOCALAPPDATA%\komai\hunspell\

Create the hunspell/ folder if it doesn't exist. The file names must keep the .dic/.aff extensions and match each other (e.g. fr_FR.dic + fr_FR.aff).

Corrections and your personal dictionary

Right-click a flagged word:

  • pick a suggested correction to replace the word;
  • Add to dictionary to accept the word permanently — it goes into a personal.dic file (one word per line) in Komai's data directory, and is shared across all your 👥 application profiles.

What is skipped

These never get flagged: URLs and email addresses, backtick-delimited code spans and fenced code blocks, @mentions, #tags, :emoji: shortcodes, all-caps acronyms, and camelCase / identifier-looking tokens.

Where things are stored

  • The on/off state and the list of enabled languages live in your per 👥 application profile config.yml (under composer.input.spellcheck.*), alongside the rest of Komai's settings.
  • personal.dic lives directly in Komai's data directory (e.g. ~/.local/share/komai/personal.dic), and any dictionaries you place manually live in a hunspell/ folder under it (see the Manual table for the path on your platform). Both are shared across profiles.

CJK languages

Chinese, Japanese, and Korean are not covered — there is no Hunspell dictionary for word-by-word checking of those, and the scripts are simply left alone (typing in them never produces a flag).