Closure Web Browser

Closure is a web browser implemented in Common Lisp, implemented using the CLIM user interface toolkit (more precisely, the McCLIM implementation of CLIM 2, plus some direct-to-X abstraction violations).


Some screenshots:

To check out the current version of the source code:

$ export
$ cvs login
Logging in to
CVS password: anonymous
$ cvs co -P closure

Here is a quickstart guide to running Closure on SBCL on GNU/Linux.

Mailing lists


  1. Start splitting it into components, prime candidates for components are:
  2. Use native McCLIM image support instead of CLX, so that other McCLIM backends (Postscript, GTk+) work
  3. Implement new features, such as text entry boxes.


David Lichteblau has updated Closure to use the external CXML libary (an improved version of Closure's original XML parser). This should bring better standards compliance and easier maintenance.
Provisional support for loading GIF files without an external helper application, thanks to the Skippy library.
OpenMCL support has been added to Closure.
It's later than mid-April, but the current version of Closure runs in current SBCL and McCLIM, and is mostly robust against the vagaries of the big bad Internet.
Currently the code base has experienced some bit rot but we expect to get it running again with current SBCL and McCLIM by mid-April. Also we did a license change from the former GPL/LGPL mix to MIT-style in an attempt to make the code more useful for integration in other projects be it free projects, GPLed projects or even closed source projects.