Twitter is today announcing the availability of Diffy, a new piece of open-source software that developers can use to spot bugs when they’re making updates to certain parts of code.

Twitter uses the code internally. Now the social networking company is releasing it to the rest of the world.

The tool should come in handy for those who frequently push new versions of code for specific parts of applications. Developers can run unit tests, but they take time.

“As the complexity of a system grows, it very quickly becomes impossible to get adequate coverage using hand-written tests, and there’s a need for more advanced automated techniques that require minimal effort from developers. Diffy is one such approach we use,” Puneet Khanduri, a member of Twitter’s tools and frameworks team, explained¬†in a blog post.

This is just the latest piece of software Twitter is providing for others to use. Other open-source tools from Twitter include Scalding and Summingbird. Facebook and LinkedIn, among others, also regularly release open-source software for others to use.

Primarily written in Scala, Diffy “acts as a proxy which accepts requests drawn from any source you provide and multicasts each of these requests to three different service instances: a candidate instance running your new code, a primary instance running your last known-good code, [and] a secondary instance running the same known-good code as the primary instance,” Khanduri wrote.

Twitter's Diffy tool.

Above: Twitter’s Diffy tool.

Image Credit: Twitter

Diffy is now available on GitHub here. Learn more about it in Khanduri’s blog post.