Korektor is a statistical spellchecker and (occasional) grammar checker released under 2-Clause BSD license and versioned using Semantic Versioning.

Korektor started with Michal Richter's diploma thesis Advanced Czech Spellchecker, but it is being developed further. There are two versions: a command line utility (tested on Linux, Windows and OS X) and a REST service with publicly available API and HTML front end.

The original OS X SpellServer providing System Service integrating Korektor with native OS X GUI applications is no longer developed, but do not hesitate to contact us if you are interested in it.

Copyright 2015 by Institute of Formal and Applied Linguistics, Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic.


The service is freely available for testing. Respect the CC BY-NC-SA licence of the models – explicit written permission of the authors is required for any commercial exploitation of the system. If you use the service, you agree that data obtained by us during such use can be used for further improvements of the systems at UFAL. If you perform corrections to the output (either by choosing other suggestions or by manually correcting the text), please use the Submit corrected text button to send the corrected text to us. All comments and reactions are welcome.

Output (editable)