iOS implementation of the Catrobat language
Objective-C Swift C C++ Shell Python
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Catty, also known as Pocket Code for iOS, is an on-device visual programming system for iPhones.

Catrobat is a visual programming language and set of creativity tools for smartphones, tablets, and mobile browsers. Catrobat programs can be written by using the Catroid programming system on Android phones and tablets, using Catroid, or Catty for iPhones.

For more information oriented towards developers please visit our developers page.


For reporting issues use our JIRA Bugtracking System. Before, please browse our currently open issues here.


If you want to contribute we suggest that you start with forking our repository and browse the code. Then you can look at our Issue-Tracker and start with fixing one ticket. We strictly use Test-Driven Development and Clean Code, so first read everything you can about these development methods. Code developed in a different style will not be accepted. After you've created a pull request we will review your code and do a full testrun on your branch.

If you want to implement a new feature, please ask about the details on or!forum/catty-ios

Learn iOS development

We recommend Developing iOS 11 Apps with Swift from the Stanford University.

Start setting up the working environment:


The Following License Header should be used for all header and source files.

License Header (for source and header files)

 *  Copyright (C) 2010-2018 The Catrobat Team
 *  (
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.
 *  An additional term exception under section 7 of the GNU Affero
 *  General Public License, version 3, is available at
 *  (
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  GNU Affero General Public License for more details.
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see