JSON Filetype

Starting with version 1.25, Geany has a built-in JSON filetype.

JSON files are intended for serializing data objects, but are sometimes used as configuration files. JSON syntax is mostly a subset of JavaScript syntax and therefore the JavaScript lexer can be used for it.

Add this to the filetype_extensions.conf file ( means existing data):


And create a new filedef named filetypes.JSON.conf with the following contents:

primary=true false null
# 0 is spaces, 1 is tabs, 2 is tab & spaces

Build Commands

For people using Unix, the following will be helpful for checking your JSON files for correctness.

if which python >/dev/null ; then
  python -m json.tool <"$1" 2>&1 >/dev/null \
  | sed 's/^\([^:]*\): line \(.*\)/'"$1"':\2: \1/'
elif which perl >/dev/null ; then
  perl -MJSON -e 'local $/;decode_json(<STDIN>);' <"$1" 2>&1 >/dev/null \
  |sed 's/^\(.*\) at .e line 1, .STDIN. [^ ]* \([0-9]*\)/'"$1"':\2: \1/;'
  echo "No known JSON parsers found" >&2
  exit 1

In Geany, go to the Build menu and 'Set Build Commands…' and use /usr/local/bin/check_json %f as the compile command, and ([^:]+):([0-9]+) as the Error Regular Expression.

Pretty Printing

Assuming you have Python installed, pretty printing (aka formatting) of JSON is very easy with Geany:

  • Python is required (works with Python 2 and 3)
  • Configure Geany: Edit→Format→Send Selection to→Set Custom Commands
  • In the dialog add a new command and simply use: python -mjson.tool

To use this, select some string in Geany and use Edit→Format→Send Selection to→<your configured command> and Geany will replace the string by the converted version. Alternatively, you can use the shortcut Ctrl-<number> in case your command is one of the first three configured commands. For details, read the documentation about Send Selection to commands.