In November 2006, I gave a public talk at Google about Mondrian, a web tool for code review on the web that I was developing at Google, for Googlers. (Watch the video.)

I've always hoped that I could release Mondrian as open source, but it was not to be: due to its popularity inside Google, it became more and more tied to proprietary Google infrastructure like Bigtable, and it remained limited to Perforce, the commercial revision control system most used at Google.

This application is the next best thing: an code review tool for use with Subversion, inspired by Mondrian and released as open source. Some of the code is even directly derived from Mondrian.

The open source project has the code name Rietveld in honor of Gerrit Rietveld, Dutch architect and furniture designer. I've chosen to use the more neutral codereview name for the live app, since most English speakers have a hard time typing rietveld correctly.

While this web app was primarily written to serve as a showcase for using Django with Google App Engine, the scalable infrastructure for web applications that I helped build, I hope that it will serve as a useful tool for the open source community, especially the Python community to which I am so indebted.

--Guido van Rossum, Python creator and Google employee