# Ratel ## Overview

If you are using an Okapi Tool after the M9 release, you should be using the wiki online help:
http://www.opentag.com/okapi/wiki/index.php?title=Ratel

Ratel is a Java application to create, and maintain segmentation rules. Segmentation rules are used in various Okapi tools and components to break down text into segments such as sentences.

Ratel implement the SRX (Segmentation Rule eXchange) standard to be compatible with other tools. You can find the specifications of SRX 2.0 here: http://www.lisa.org/fileadmin/standards/srx20.html.

This editor can load SRX version 1.0 documents, but they will be saved as version 2.0 documents. You will be warned both when opening and saving SRX 1.0 documents. Be aware that versions 1.0 and 2.0 of SRX may be incompatible depending on how the version 1.0 document was interpreted by the tool that created the file. For more information about SRX versions, see the SRX Versions Issue section.

Ratel and the all the components of the Okapi Framework are free and open-source.The application runs on top of Java (version 1.5 and higher) and runs on any platform where SWT is supported, including the Windows, Linux and Macintosh systems.

To get started with Ratel, please read:

- How to Use Ratel
- Main Window