The Twitter Engineering Blog

Information from Twitter's engineering team about our technology, tools and events.

Results from Engineering for: March 2011

Improving Browser Security with CSP

If you are using Firefox 4, you now have an extra layer of security when accessing


The Great Migration, the Winter of 2011

If you look back at the history of Twitter, our rate of growth has largely outpaced the capacity of our hardware, software, and the company itself. Indeed, in our first five years, Twitter’s biggest challenge was coping with our unprecedented growth and sightings of the infamous Fail Whale.


Building a Faster Ruby Garbage Collector

Since late 2009, much of has run on Ruby Enterprise Edition (REE), a modified version of the standard MRI 1.8.7 Ruby interpreter. At the time, we worked with the REE team to integrate some third-party patches that allowed us to tune the garbage collector for long-lived workloads. We knew this was not a perfect choice, but a switch to a new runtime (even MRI 1.9x) would introduce compatibility problems, and testing indicated that alternative runtimes are not necessarily faster for our workload. Nevertheless, the CPU cost of REE remained too high.