--- title: User Agent mandatory from March 4th 2013 author_name: agh --- Following on from our [previous post](http://developer.github.com/changes/2012-10-14-rate-limit-changes/) about requiring requests to include a valid [User Agent header](http://en.wikipedia.org/wiki/User_agent) we will soon be changing our API servers to return HTTP 403 to any clients not providing a valid User Agent header. We will be making this change on Monday, March 4th 2013. Setting this helps us identify requests from you, and get in touch with people who are using the API in a way which causes disruption to GitHub. Most HTTP libraries and tools like cURL already provide a valid header for you, and allow you to customize it, so this will not require many of our users to make any changes whatsoever. If you have any questions or feedback, please drop us a line at [support@github.com](mailto:support@github.com?subject=User Agent Requirement).