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msolo edited this page Dec 7, 2019 · 6 revisions

SIMBL is the SIMple Bundle Loader.

It enables various plugins like PithHelmet to run in Cocoa applications such as Safari.

Current Release

Installing SIMBL Plugins

Most plugins should come with an installer, however it's easy to do it yourself.

Plugins can be copied into /Library/Application Support/SIMBL/Plugins for all users, or ~/Library/Application Support/SIMBL/Plugins for just your account.

SIMBL plugins are nothing more than standard Cocoa bundles created by XCode, with the addition of one key in the Info.plist. For further information, you can read the SIMBL section in my brief tutorial on Cocoa hacking.

SIMBL was originally created when I was working on PithHelmet, but here are now a bunch of SIMBL plugins available. If you don't see yours listed, feel free to edit the list on the wiki.


If you think you've hit a bug, check the FAQ. If you're question hasn't been answered there, peruse the Issues List.


The brave can try and make sense of the change log.


There are a number of SIMBL plugins to enhance a number of applications.


For more information about developing plugins that use SIMBL, you can try following the SIMBL tutorial. You could also skip to the troubleshooting section.

If you are interested in modifying a particular Cocoa application, read the Armchair Guide to Cocoa Reverse Engineering.


A few people have asked about licensing terms, etc. SIMBL is licensed under the GNU GPL v2

Let me explain in terms I understand:

  • You can use SIMBL for anything you like.
  • You can include the SIMBL.pkg with your distribution, but you need to include the original license and ReadMe files so people know what they are getting.
  • If you want more from SIMBL, check out the source and make change suggestions. You can modify the code, but if you release it, you must release the source code as well. On a more general note, please do not distribute a modified version of the code under the SIMBL name -- it would make my life a nightmare. If we can't work your changes into the real SIMBL, give it another fairly different sounding name!
  • There is no warranty of any kind. (I'll do my best to help you if a problem surfaces, but no guarantees...)
  • If you are using SIMBL in a commercial product, please make a donation to support this project.

The point of the license is to be as flexible as possible - basically, it shouldn't get in the way of writing some cool hack. One of the main reasons I wrote SIMBL was because I didn't like the somewhat draconian terms of the APE license.