The screenshot shows Flycheck on Emacs 24.3.50 with the awesome Solarized Light color theme and the great Source Code Pro font.

Flycheck is a modern on-the-fly syntax checking extension for GNU Emacs 24

• Features
• Flycheck versus Flymake
• Supported Languages
• 3rd party extensions

Flycheck needs Emacs 24, and works best on Unix systems (i.e. Linux or OS X).

Note: For almost all supported languages, Flycheck also needs additional external programs. See Supported Languages for a list of supported languages and the corresponding checker programs, and use C-c ! ? to get help about specific checkers inside Emacs.

Install the ELPA package from MELPA or Marmalade with M-x package-install RET flycheck.

In your Cask file:

(source gnu)
(source melpa)

(depends-on "flycheck")

See Installation for detailed installation instructions.

• User Manual
• Issue tracker

• Github
• Contribution guidelines

• Contributors
• Credits

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

See COPYING for details.

The Flycheck documenation is free documentation: you can copy, distribute and/or modify it under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is available at https://github.com/flycheck/flycheck/blob/master/doc/fdl.txt.

Alternatively, you may copy, distribute and/or modify the Flycheck documentation under the terms of the Creative Commons Attribution-ShareAlike 4.0 International Public License. A copy of the license can be obtained at https://creativecommons.org/licenses/by-sa/4.0/legalcode.