Google Code Search

Google Code Search
Type of site	Search engine
Available in	All languages
Owner	Google
URL	www.google.com/codesearch
Launched	October 5, 2006; 18 years ago
Current status	Discontinued as of 7 May 2025

Google Code Search was a free beta product from Google which debuted in Google Labs on October 5, 2006, allowing web users to search for open-source code on the Internet. Features included the ability to search using operators, namely lang:, package:, license:, and file:.

The code available for searching was in various formats including tar.gz, .tar.bz2, .tar, and .zip, CVS, Subversion, git and Mercurial repositories.

Google Code Search covered many open-source projects, and as such is different from the "Code Search for Google Open source projects" that was released afterwards.^[1]^[2]

Regular expression engine

The site allowed the use of regular expressions in queries, which at that time was not offered by any other search engine for code.^{[citation needed]} This makes it resemble grep, but over the world's public code. The methodology employed, sometimes called trigram search, combines a trigram index with a custom-built, denial-of-service resistant regular expression engine.^[3]

In March 2010, the code of RE2, the regular expression engine used in Google Code Search, was made open source.^[4]

Google Code Search supported POSIX extended regular expression syntax, excluding back-references, collating elements, and collation classes.

Languages not officially supported could be searched for using the file: operator to match the common file extensions for the language.

Discontinuation

In October 2011, Google announced that Code Search was to be shut down along with the Code Search API.^[5] The service remained online until March 2013,^[6] and it now returns a 404.

In January 2012, Google developer Russ Cox published an overview of history and the technical aspects of the tool, and open-sourced a basic implementation of a similar functionality as a set of standalone programs that can run fast indexed regular expression searches over local code.^[7]